CA1211147A - Tandem commutatorless dc machine - Google Patents
Tandem commutatorless dc machineInfo
- Publication number
- CA1211147A CA1211147A CA000477289A CA477289A CA1211147A CA 1211147 A CA1211147 A CA 1211147A CA 000477289 A CA000477289 A CA 000477289A CA 477289 A CA477289 A CA 477289A CA 1211147 A CA1211147 A CA 1211147A
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- Canada
- Prior art keywords
- machine
- air gaps
- magnetic
- rotor disk
- establish
- Prior art date
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K31/00—Acyclic motors or generators, i.e. DC machines having drum or disc armatures with continuous current collectors
Abstract
Abstract A commutatorless DC machine (10) is disclosed having axially oriented magnetic flux in the air gaps between interleaved stator and rotor disks, wherein the rotor disks (16) carry one or more radially oriented armature winding elements (32) consisting of electrical conductors serially interconnected in serpentine fashion and terminated at a pair of slip rings (30F/R). The magnetic flux incident upon the two opposed planar surfaces of any one rotor disk are oppositely directed thereby producing electro-motive forces or torques which are directly additive, resulting in heretofore unrealized electromechanical transducer actions.
A number of illustrative and preferred embodiments describe single or multiple rotor disk configurations; also describe armature winding arrangements having various numbers of indivi-dual armature winding elements arranged in parallel between the slip rings; and further describe an improvement wherein a number of basic units are combined into a tandem arrangement (400). The resulting DC machines exhibit superior electrical and mechanical performance due to, among other factors, the absence of limita-tions imposed by commutation; and also may be designed for a wide range of electrical and mechanical requirements simply by the addition or deletion of disk sections and/or armature winding elements and/or tandem units.
A number of illustrative and preferred embodiments describe single or multiple rotor disk configurations; also describe armature winding arrangements having various numbers of indivi-dual armature winding elements arranged in parallel between the slip rings; and further describe an improvement wherein a number of basic units are combined into a tandem arrangement (400). The resulting DC machines exhibit superior electrical and mechanical performance due to, among other factors, the absence of limita-tions imposed by commutation; and also may be designed for a wide range of electrical and mechanical requirements simply by the addition or deletion of disk sections and/or armature winding elements and/or tandem units.
Description
TANDEM COMMUTA~ORLESS DC MACHINE
Technical Field The present invention relates generally -to commutator less DC
machines of the axial air gap type which readily function as either DC motors or DC generators. Specifically, the present invention relates to a DC machine having a plurality of disk-like stators elements and one or more interleaved disk-like rotor elements adapted to produce axial magnetic flux in the air gaps between their adjacent planar surfaces, and employing umquely configured, radially oriented armature conductor winding elen~nts rotatable in the air gaps to produce the desired electromechanical transducer actions. Both a basic embodiment, and an improved embodiment comprising a number of basic units in tandem are disk closed.
Background Art Both ccmmutatorless rotary machines and axial air gap rotary machines are well known in the electrical engineering art, and have been the subject of much study and development over the years.
In their most basic forms, these two features are often found in machine embodiments wherein thy magnetic flux passes in the same direction from one member to the other over the whole of a single axial air gap area, and are designated as cyclic, or alternatively as homopolar machines While the present invention goes very far beyond the basic cyclic approach and represents an entirely new family of DC machines, it is of some interest to briefly describe prior art machines exhibiting the commutator less and axial field features.
US. Patent 1,465,251 to Broluska et at discloses an early (1920) commutator less DC machine having a plurality or inter-leaved stators and rotor disks wherein radially oriented armature conductors are immersed in axially directed magnetic fluxes to produce either motor or generator action The design however, employs a totally unidirectional magnetic flux which is customary and conventional. This purely unidirectional field approach, unfortunately calls for the segmentation of the armature conductors, which in turn gives rise to the need for a set of collector rings and rollers which engage the outer circumferences of the roller disks. The technical necessity for the collector ring structure is well documented, and a rigorous presentation of the phenomenon involved may be found in the description of the "Multi-Spoke Wheel" generator on pages 57-69 of the text "Flux Linkages and Electromagnetic Induction"
by LO Boyle. (Dover Publications, New York, 1964).
More recent prier art homopolar machines are exemplified by US. patents 3,743,874 to Shabbier and 3,699,370 to Colloidal.
Additional prior art approaches in the area of commutator less and/or axial field machines are disclosed in US. patents 3,169,204 to Myers et at; 4,082,971 to Mohawk et at; 4,187,441 to Only; and in an IBM TUB authored by C. Dung, dated March 10, 1981.
Summary Of The Invention __ It is therefore a primary object of the present invention to provide an improved commutator less DC machine which may readily function as either a DC motor or a DC generator.
Another object of the present invention is to provide a DC machine which will be largely devoid of the design limitations and operational problems associated with the use of conunutation devices of all types.
, ,=~" I, ,, .
A further object of the present invention is to provide a basic commutator less DC motor having axially oriented magnetic flux between Lnterlea~ed stout and rotor disks, wherein the rotor disks carry radially oriented armature conductors which are uniquely interconnected and terminated at a pair of slip rings; and wherein the magnetic flux incident upon the two planar surfaces of any one rotor so are oppositely directed thereby producing net torques which are directly additive resulting in heretofore unrealized superior DC motor performance.
A yet further object of the present invention is to provide a basic commutator less DC generator having axially oriented magnetic flux between interleaved stators and rotor disks, wherein the rotor disks carry radially oriented armature conductors which are uniquely interconnected and terminated at a pair of slip rings; and wherein the magnetic flux incident upon the two planar surfaces of any one rotor disk are oppositely directed thereby producing ems which are directly additive resulting in hereto-fore unrealized superior DC generator performance.
A still further object of the present invention is to pro-vise an improved co~mutatorless DC machine wherein the advantages of the basic DC motor and basic DC generator outlined above are achieved by combining a number of the basic unit together in tandem.
By means of a number of illustrative and preferred basic and improved embodiments, the present disclosure teaches the broad principles of a DC machine having axially oriented magnetic flux between interleaved Syria and rotor disks herein the rotor disks carry radially oriented armature conductors which are uniquely it reconnected and terminated at a pair of slip rings. The mug-netic flux incident upon the two planar surfaces of any one rotor disk are oppositely directed thereby producing ems or torques, which are additive resulting in heretofore unrealized electromagnetic transducer actions.
Brief Description s Additional objects and advantages of toe invention will become apparent to those skilled in the art as the description proceeds with reference to the accompanying drawings wherein:
FIG. 1 is half of a vertical cxoss-section through a basic embodiment of a commutator less DC machine according to top present invention;
FIG. 2 is a detailed vertical cross-section of the rotor assembly shown in FIG. l;
FIG. PA and 3B snow side and end views, respectively, of a typical rotor flange;
FIG. 4 is a detailed vertical cross-section of the stators assembly shown in FIG. l;
FIGS. PA and 5B show side and end views, respectively, of an illustrative plain type stators flange;
FIGS. PA and ÇB show side and end views, respectively, of a typical core type stators flange FIG. 7 is a highly schematic perspective drawing ox a complete armature winding arrangement or a four-windinq-element, three-section DC machine according to the present invention;
FIG. R it a simplifies electrical equivalent circuit cores-pounding to the complete armature winding arrangement of FIG. 7 when used as a DC generator;
FIG. 9 is a simplified electrical equivalent circuit of a complete armature winding arrangement for an eight-winding-element, seven-section DC machine when used as a DC Myra FIG. 10 is a simplified electrical equivalent circuit of : a typical four winding stators field arrangement;
FOG. 11 shows typical magnetic circuits and flux paths of the basic embodiment of FIG. 1, in highly schematic form;
FIGS. 12 and 13 show enlarged portions from FIG. 11) of typical magnetic circuits and flux paths in Fleming's Rules interaction regions for, respectively, operation as DC motors, and as DC generators;
4'7 FIG. 14 is a vertical-cross section through an improved em-bodiment of a commutator less DC machine according is the present invention;
FIG. 15 shows typical magnetic circuits and toe resulting flux paths of the improved embodiment of FIG. 14, in highly schematic form;
FIG. 16 is a perspective drawing of a composite armature winding arrangement for a four-winding-element,eleven-section, three machine unit configuration corresponding to the improved embodiment of FIG. 14;
PIG. 17 is a simplified electrical motor equivalent circuit corresponding to PIG. 16, showing the array of torque producing means;
FIGS. AYE and 18B show a simplified electrical equivalent circuit of a typical four-winding, three machine unit stators field arrangement;
FIG. 19 shows operating polarities/senses of a tandem DC
machine while functioning as a commutator less DC motor;
FIG. 20 is a simplified electrical generator equivalent circuit corresponding to FIG. 16, showing the array of voltage producing means; and FIG. 21 shows operating polarities/senses of a tandem DC
machine while functioning as a co~mutatorless DC generator.
Detailed Description of the Preferred Embodiments A Basic Embodiment referring first to FIG. 1, there is shown a basic embodiment of a commutator less DC machine according to the present m mention.
FIG. 1 shows half of a vertical cross-section through a multiple disk, simply configured DC machine 10. As a brief introduction, an overall DC machine 10 is shown as comprising two major sub-assemblies including a multiple flange rotor assembly 12, rotatable mounted within a multiple mating flange stators assembly 14. The rotor assembly 12 includes a plurality of spaced apart rotor flanges 16 assembled onto a central shaft 18 which is concentric with a machine axis of rotation 20. The stators assembly 14 includes a corresponding plurality tress one) of spaced apart stators flanges 22, mounted within a hollow cylindrical yoke 24, which yoke forms part of the outer casing of the DC machine 10. A pair of circular end yokes 26F and 26R are affixed to the front and rear ends respectively of the cylindrical yoke 24 to form an enclosed compar~ent. The ends of the central shaft 18 pass through the end yokes 25F and 25R via circular openings 28F and 28R, respect-lively, and the shaft ends ye suitably retained and fitted with bearings snot shown) by well-known and conventional means. A pair of slip rings 30F and OR are concentrically affixed on alternate ends of the central shaft 18 and serve as the electrical input/output terminals for a plurality of armature wind in elements distributed over the rotor flanges. A typical armature winding element 32 is shown in cross-section as being terminated at its forward end to the slip ring 30F via a contact 34, and at its rearward end to the slip ring 30R via a contact 36. The armature winding element 32 is con-figured as a discreet electrical wire-like conductor, shaped to follow the outer contours of the plurality of rotor flanges, and appears in cross-section as a continuous and fairly regular serpentine path confined to a particular radial plane, as is detailed below.
I '7 The structure and functions of each of the above elements, as well as additional elements, are described in more detail herein below. It is worthy of note that thy! elements outlined above are applicable to operation of the DC machine 10 as either a commute-topless DC motor or as a commutator less direct DC generator. The term "direct DC" denotes that as a DC generator, the output voltage is produced as a continuous unidirectional output and does not require commutator action for rectification into DC.
Referring now to FIG. 2, there is shown a detailed vertical cross-section of the rotor assembly 12 of FIG. 1. In the basic embodiment of FIG. 1, a seven-section DC machine is shown, the seYen-sectio~ rotor assembly depicted corresponds to that embody mint. The rotor assembly 12 is pictured as comprising a plurality of rotor flanges 16 longitudinally stacked along the central shaft 18. Reference to FIGS. PA and 3B show each of the flanges 16 to be generally disk shaped, and to haze a thickness in the axial (or longitudinal direction at its outer periphery of "if". The flanges 16 further have a rim boss 38 at their inner periphery, and a centrally located opening 40 to admit toe central shaft 18. The rim boss 38 has an axial extent slightly larger than tub tycoons "t " of the flange, and a radial dimension "rub" very much less than the radial dimension "or" of the flange The flanges 16 are made of material having predetermined desired magnetic properties and may illustratively be of forged or cast steel. When assembled as a seven-section embodiment as shown, the seven individual flange 16 (plus front and rear magnetic end pieces 38l and 38") create an armature core region 42 by virtue of the increased mass of mug-netic material provided by the thickened rim kisses and end pieces being longitudinally stacked. Thy armature core region 42 (India-acted generally by the multi headed arrow symbol of FIG. I so formed functions similarly to the armature core of a conventional DC machine. The central shaft 18 may be made of steel suitable for supporting the various rotor components during their high speed rotation operation, and the entire assembly may be fastened together by conventional means.
A wide variety of complete armature winding arrangements may be used in conjunction with the rotor assembly of FIG. 2 depending on the basic use to which the machine is being put (i.e., motor or generator); and further depending on the particular electrical and mechanical characteristics (i.e., electrical power/torque/speed) which it is desired that the machine is to exhibit. In the embodiment of FIG. 2, two armature winding elements are shown. These are winding elements 32 and 32', both of which are identical and contain a to-tat of seven contoured portions, corresponding to the number of rotor flanges of the embodiment. Only the winding element 32 will be described, it being understood that the winding element 32' (plus other winding elements equally spaced circumferential around the rotor flanges - not shown) will be identical. Basically, the winding element 32 is a count m use electrical conductor, such as a length of copper wire, formed into a serpentine contour to fit along the surfaces of each of the stack Go rotor flanges in a rotor assembly. For purposes of clarity, the winding elements 32 and 32' are shown as affixed on the outer surfaces of the flanges. Winding elements 32 and 32' ye confined to a single plane containing thy axis of rotation 20, around which axis the plane (and the two winding elements rotate. The plane containing the wincing element 32 is bounded at its radially inwards extremity (lower edge as shown) by - a tine parallel to the axis 20, and the plane containing the winding element 32' is bounded at its radially inwards extremity (upper edge as shown) by a line parallel to the axis 20. In an alternate embo-Dante, the winding elements may be affixed into shallow slots (not shown) formed into the flat side surfaces of the rotor flanges. Each extremity of the winding element 32 is connected to its adjacent slip ring for electrical contact. The slip ring 30F is mounted around the 3Q magnetic end piece 38' and insulated from it (concentrically with the rotational axis 20), and connects with the winding 32 at the contact point 34. Slip ring CRY is similarly insultingly mounted around the magnetic end piece 38" and connects with the winding 32 at the contact point 36.
'7 A clearer description of complete armature winding arrangements contemplated may be had with reference to the perspective drawing of FIG. 7, along with its corresponding simplified electrical equivalent circuit of FIG. 8, m addition to the aforementioned FIGS. 2, PA
and 33. FIG. 7 shows a complete armature winding arrangement for a DC machine coI~prisi~g, illustratively, a three-section rotor assembly (i.e., three rotor flanges); and also comprising, illustra-lively, four armature winding elements of the type 32 circumferen-tidally spaced at 90 intervals around the rotor flanges. The winding element designated as 32(0) corresponds nominally to the winding element designated 32 in FIG. 2; while the winding element design-ted 32tl80) corresponds nominally to the winding elements design noted 32' in PIG. 2. The winding elements 32~0 s d 32(270) which are not shown in FIG. 2, along with the 32(0) and 32(180) winding elements are all connected in electrical parallel via Lye termination of their corresponding extremities on slip rings 30F
and 30R. The number of rotor sections it shown in FIG. 7 as being three, as compared to the even section embodiment of FIG. 2, largely to provide an uncluttered illustration. In actual co~mutatorless DC machines designed according to the principles taught herein, it is contemplated that the number of rotor sections could be as few as one, or as many as several dozen or more.
In the electrical equivalent circuit of FIG. 8, which is shown for the case where the DC machine is being operated as a DC generator, it is seen that the winding element designated 32C0) comprises six independent em generators depicted as a pair of adjacent circle/
dot symbols I each circle of which corresponds to a radial portion of an armature minding element. Thus, the winding portion a-b-c-d corresponding to the first one of the three sections of winding ODE) of FIG. 7 is electrically equivalent to the two em generators designated a-h and c-d of the first one of the three sections of winding 32(0l of FIG. 8. In like manner, the two other sections of winding 32(0l, namely e-f-g-h and i-j-k-l of FIG. 7 translate into the four em generators e-f and g-h, plus i-j and k 1 of FIG. B. The remaining windings 32C90), 32(180), ~~ 7 and 32 (270), of both FIG. 7 and Fit;. 8 are similarly related. In short, a complete armature winding arrangement consists of a number of armature winding elements, each spanning from one slip ring to the other; all of the armature winding elements being in parallel between the slip rings. Conventional sets of brushes (not shown contact the slip rings, and leads Fran the bushes are brought out to the machine terTninal board for suitable external interconnections.
A further alternate embodiment of the present invention is shown by way of the simplified electrical equivalent circuit of FIG. 9.
This embodiment depicts the DC machine 10 while it is bring operated as a commutator less DC motor. By reference to a plurality of torque generating elements depicted as a pair of adjacent circles "-00-"
yin positions analogous to the em generators of FIG. I there is shown a seven section DC machine. The c~nplete armature winding arrangement comprises eight separate winding elements, each generally of the type 32, spaced 45 degrees apart. These eight windings are designated 32(0), 32(45~), . . . 32(315). Each armature winding element has a total of fourteen torque generators (seven prows) with the third pair in the 32(0) winding designated as consisting of an it part and a clue* part. As before, the individual torque generating elements are associated only with the radial portions of the armature winding elements. A fuller descrip-lion of the modes of operation of the ccmmutatorless DC Tnachine 10 as both a motor and also as a generator is provided hereinbelow.
Referring now Jo FIG. 4, there is shown half of a detailed Yen-tidal cross-section of the stators assembly 14 of FIG. 1. The assembly 14 is pictured as c~nprising a plurality of stators flanges 22 assembled within the cylindrical, longitudinal yoke 24, all of which is rapped by a pair of end yokes 26F and 26R. longitudinal bolts (not shown) may be used to align and fasten the various come pennants together in any conventional nunnery. By reference to FIGS.
PA, 5B~ PA, and 6B, in addition to FIG. 4, the stators flanges 22 art shown to be of two distinct types. These types are designated a stators core flange 22C, and a stators plain flange 22P. The plain type flange 22P of FIGS. PA and 5B is shown a generally disc-shaped, and having a thickness at its inner periphery of "t ". The plain flanges 22P further have a rip boss 44 at the outer periphery on one side, and a centrally located Gore of radius "r ". The rim boss 44 has an axial extent approximately the same as the thickness "t "
and a radial extent very much less than the dimension "us" of the flange 22P. Momentary reference to the overall DC macho of FIG.
1 shows that the central bore 46 has radius "r " slightly larger than the radial dimension "rub" of the boss 38 shown in FIG. 3B, allowing the rotor assembly 12 to rotate smoothly within the stators assembly 14.
The core type flange 22C of FIGS. PA and 6B is shown as also being generally disk-sha~ed,and having a thickness at its inner periphery of "t ". The core flange 22C also has a rim boss OR at its outer periphery on one side, and further has four radial pole core projections 50 spaced at 90 degree intervals around its air-cumference. The rim boss 48 extends over the pole core projections 50. Except for the presence of the core projections 50, the overall configurations and dimensions of the core flange 22C are the same as those of the plain flange 22P. On close assembly, these pole core projections 50 for a pole core region 52 (its extent indicated generally my the associated multiple headed arrows around which a field core winding 54 is wound. Of the four projections shown in FIG. PA, only one pole core region 52 is shown in FIG. 2. It is to be understood that the four pole core configuration shown is illustrative only, and that the actual number of poles to be used in any particular DC machine is largely established as a matter of design choice. Thus, DC machines according to the present invention may contain more or less pole core projections, and may also be of odd or even numbers.
A cylindrical stators core region 56 (its extent indicated generally by the associated multiple headed arrows is formed by the close assembly of the plain type and core toe stators flanges.
As with the pole core region 52, this g atop core region 56 is not a separate component as such, but is defined largely in terms of its function. the function of the stators core region 56 is similar aye to that of pole shoes in a conventional DC machine. Additional pieces of magnetic structure such as an end piece 57 may be included as necessary to suitably shape the magnetic circuit paths. Further, in selected alternate embodiments of the stators assembly 14, supple-Monterey plain flanges 22P* (indicated in dotted lines as slightly modified, i.e., not having significant rim bosses 44) may be in-eluded at the forward and rearward ends of the stators assembly to produce a stators flange/rotor flange interleaving arrangement wherein all rotor flanges 16 are surrounded on both of their planar sun faces my stators flanges of the types 22C and/or 22P and/or 22P*.
In the embodiment of FIG. 4, separate field coils would be mounted on each of the four pole core regions (only one shown) and the ends of each of these coils are brought out to the DC machine terminal board (not shown) for mutual and external electrical con-sections. A simplified electrical schematic of the stators field windings is shown in FIG. 10 as four identical sets of field windings 54 connected in series and brought out to a pair of terminals " "
and "En"- The particular arrangement of field windings is largely - determined by the design requirements a given machine is a responseto. The number of individual coils (such as the single field core winding 54) on each pole core and their specific winding and inter-connection pattern is dependent on the type of DC machine contem-plated. Illustrative DC machine types include separately excited, shunt excited, series excited and compound excited. Audi, field control rheostats external to the DC machine (not shown) may be employed as part of the excitation source applied to the " "/" "
terminals. While toe arrangement of field windings is a matter of design choice, it is significant to observe in the embodiment of FIG. 10 that the resulting magneto motive force (hereinafter mmf), as depicted by the arrow symbols "-I ", are unidirectional. In this case, all four "--I " are directed radially inwards to pro-dupe the desired magnetic circuit paths, as is detailed below.
Based on the structures detailed above, a description of the operating principles of the DC machine both as a DC motor and as a DC generator is now facilitated. While the rotor and stators electrical circuits are comparatively straightforward, the magnetic circuits of the present invention contrast significantly with the magnetic circuits ox the conventional DC machine, and warrant special attention. Referring now to FIG. 11, there is shown half of a typical magnetic circuit and the resulting flux paths of the basic embodiment DC machine shown in FIG. 1. To provide improved emphasis on the magnetic circuit paths of interest, a number of symbols have been omitted from this drawing, but it is to be under-stood that FIG. 11 represents the same seven-section DC machine described in connection with FIGS. 1, 2 and 4.
In operation, all of the yield coils of the DC machine are excited from a suitable DC source such that the my produced by the field coils can be made to be directed either radially inwards or radially outwards depending on the direction of the currents in the coils. The direction chosen does not matter to establish the operating principles. In the present description, all of the field coil excitations are chosen so as to produce mmf's directed radially inwards such that all of to pole cores have radially inward directed magnetic fluxes. This flu gets distributed as shown in the stators core to all the stators flanges, and takes the two major paths indicated by two sets of flu arrows - F _ and I - to axially cross the air gaps 58 between contiguous stators and rotor flange surfaces over their overlapping portions. There-after as shown by the arrows, the flux paths enter the rotor flanges; reach the armature core; and travel allele towards the front (or rear of the machine towards the encase. The flux paths then cross the two very thin air gaps between 38' and 38" to reach respectively, the end yokes 26F and 26R; whereupon thy flux travels radially outwards in the two end yokes; then turns to travel axially inward towards the pole in the longitudinal yoke 24; and finally returns to the pole core regions 52, thereby completing the magnetic circuit. Because of the symmetry of parts, there are two it symmetrical magnetic circuit paths beyond the pole cores. The for-warmly extending circular path (towards 26F) making a clockwise pat-tern indicated generally by its arrow ; and the rearwardly extending circular path (towards 26R~ making a counterclockwise pattern indicated generally by its arrows I - .
he flux in the air spaces 58 sandwiched by the rotor and stators flanges (hereinafter called the air gap or air gap flux) has the following features of importance. Firstly, the air gap fluxes are substantially all axially directed. Secondly, the air gap fluxes leave the stators flange surfaces substantially normal to the surfaces, and Roth the forwardly and rearwaxdly facing surfaces of all stators flanges act as if they are flux emitter surfaces. idly the air gap fluxes enter the rotor flange surfaces substantially normal to those surfaces, and both the forwardly and rearwardly facing surfaces of all the rotor flanges (except for the end flanges) act as if they are flux collector surfaces. As will be described below, the magnetic flux incident upon the two planar surfaces of any one rotor flange are oppositely directed - i.e., Roth fluxes are interiorly directed Gore detailed description of the magnetic circuits and flux paths is facilitated by reference to FIGS. 12 and 13 which show enlarged portions of a typical rotor/stator interaction areas extracted from FIG. 11. In both FIGS. 12 and 13, the path DEFGHI shows a typical portion of the armature winding element.
(These capital-lettered conductor paths are generally the same as those indicated in lower-case letters in FIG. 7). As seen, lengths EN and GO have radial runs, while lengths DE, FOG, and I have axially runs. It it significant to note that the interaction it linkages) of the magnetic flux with the axial Hun portions (DE, FOG, and HI) is assent, because the magnetic flu and these conductor lengths are parallel, and/or lie in fringe magnetic field regions. Over the radial run portions (i.e., EN and GO
the length of the conductor lying in the magnetic field air gap 58 has full interaction Linkages with the air gap magnetic flux, because the two are normal to each other. The above flux/conductor orientations are typical, and extend over the full run of each armature winding element. The same relationships obtain for all other winding elements in a complete armature winding arrangement Considering now operation of the DC machine 10 as a comma-tutorials DC motor, let all the field coils be excited to establish a magnetic field as shown in FIG. 12. Note that the flux path designated err - divides further into two paths in the stators flanges to enter each rotor flange from opposite directions. Thus, the rotor flange within the conductors EN and GO experiences front-to-rear directed flux from the stators flange emitter surface closest to the EN surface; and that the same rotor flange experiences rear-to-front directed flux from the stators flange emitter surface closest to the GO surface. jet the forward slip ring 30F of the machine be connected to a suitable external DC source (through a stating rheostat, not shown) positive terminal, and the rearward slip ring 30R be connected to the negative terminal. The direction of the resulting armature current is shown by motor current arrows - I . The interaction of the air gap magnetic flux with the orthogonally oriented current carrying conductor portions causes mechanical forces on the conductor. Applying Flings Left-Hand Rule (the motor rule) and looking at the machine from the rearward end of the shaft, the mechanical forces on the conductors EN and GO
are both in the clockwise direction. These forces constitute a clockwise torque T on the rotor assembly 12. This condition extends over the particular armature winding element 32, and further over the complete armature winding arrangements, for the portions of the conductors similarly disposed. All of these forces being additive, a large resultant torque is created on the rotor assembly thereby producing the desired operation as a DC motor.
on operation, the commutator less DC motor of the present invention exhibits the usual rotary device properties such as counter em, losses, and the like.
Considering operation of the DC machine 10 as a commutator less DC generator, let all the field coils again be excited to establish a magnetic field as shown in FIG. 13 identical to that of FIG. 12).
Ill the rotary shaft 18 be coupled to a prime mover to cause clock-I., I
wise rotation looking from the rearward end of the DC machine.
Consider the interaction of the air gap flux as before with the now rotating active armature conductor portions EN and GO. Applying Fleming's Right Rand Rule (the generator rule the conductors experience dynamically induced ems, the directions of which are from H to G and from F to E as shown by the induced current arrows I in FIX. 13. These ems are directly additive in thy winding element. This condition extends over the particular armature winding element 32 and for the complete armature winding element arrangements, for the conductors similarity disposed. All other portions of armature conductors disposed substantially differently from EN and GO do not produce any induced ems. Thus the DC machine 10 operates as a DC generator and produces the resultant em between the two slip rings, the onward slip ring attaining positive polarity, and the rearward slip ring attaining negative polarity. The DC
machine functioning either as a motor or as a generator can be loaded as in conventional DC machines, and control similar to those used in conventional DC machines may be incorporated into it. Further, the DC machine can be built for different types of excitation to obtain different characteristics as in conventional DC machines.
In summary, it is noted that basic commutator less DC machines acting either as motors or as generators may be realized using the teachings of the present invention, which simultaneously exhibit the following desirable properties. Commutators of all types are specifically absent thereby completely eliminating the full range of electrical problems they present, and further eliminating the design limitations they conventionally impose on rotating machines. Direct current exists in all of the armature winding conductors, and slip rings only are used as electrical inputs or outputs from the machine. Thy stacking of any number of separate disk (both rotor and stators sections along with the straightforward armature winding arrangements, permits the realization of commutator less DC machines for operation at almost literally any voltage or current desired.
An Improved Embodiment Referring now to FIG. 14, there is show an improved embo-dominate of a commutator less DC machine according to the present invention. FIG. 14 shows half of a vertical cross-section through a multiple disc, tandem configured, commutator less DC machine 400.
Brief reference to FIG. 1 shows that the tandem configuration of FIG. 14 contains largely the same structural elements as the simply configured (basic embodiment of FIG. 1. Thus, the structural elements of FIG. 14 which perform substantially the same functions as those of FIG. 1 are correspondingly numbered (with differing prefixes) as an aid to clarity.
Briefly, the improved DC machine 400 is shown as comprising three rotor/stator units in tandem - designated as a central machine unit 100, a forward end machine unit 200, and a rearward end machine unit 300. Taken by to selves, each of the three tandem units functions generally the same as the single unit of the basic embo-dominate. However, the addition of the two end units produces new and highly useful operating modes which give rise to a marked imp provement in machine operation as is described below. While correspondingly numbered, the various structural elements are designated by differing leading digits which designate their distinct positions within the overall DC machine 400. For instance: central shaft 118 corresponds functionally to central shaft 18; and pole core region 152 of the central unit 100, plus pole core region 252 of the forward end unit 200, and pole core region 352 of the rearward end unit correspond functionally to pole core region 52. However, as will be described, end flanges 402F and 402R do not correspond to end yokes 26~ and 26R.
In FIG. 14, a hollow cylindrical yoke 124 houses stators asset-bites 114, 214, and 314 which are functionally associated with the central, forward, and rearward machine units respectively. Each of these assemblies comprises spaced apart stators flanges 122, 222 and 322, which are shaped and assembled to create pole core regions 152, 252, and 352, as well as stators core regions 156, 256 and 356 - when I
energized by their respective field core windings 154, 254 and 354.
A pair of circular nonmagnetic end flanges 402F and 402R are affixed to the forward and rearward ends respectively of the cylindrical yoke 124 to form an enclosed compartment. me ends of the central shaft 118 pass through the end flanges 402F and 402R, and are suitably no-twined and fitted with bearings snot shown) m the regions 404F and 404R by well-known and conventional means.
The central shaft 118 (which is concentric with a machine axis of rotation 120~ carries three flanged rotor assemblies 112, 212, and 312, which are functionally associated with their cores-pondingly positioned central forward and rearward machine unit asset-bites. Each of these rotor assemblies comprises spaced apart rotor flanges 116, 216 and 316, on which are formed armature winding elements 132, 232, and 332 respectively. Each rotor assembly further comprises a concentric pair of slip rings FRY, 230F/
230R and FRY. As before, these armature winding elements are shown in cross-section, and each is terminated at its forward and rearward ends to its correspondingly lettered slip ring.
(i.e., the forward end of armature winding element 132 is terminated on slip ring 13aF, and the rearward end of armature winding element 132 is terminated on slip ring 130R; similarly for armature winding elements 232 and 332.
In the improved embodiment of FIG. 14, the central unit 100 is shown as having five illustratively) longitudinally stacked rotor flanges of thy type 116 which produce an armature core region 142, while the forward end unit 200 is shown as hazing three (illustratively) longitudinally stacked rotor flanges which produce an armature core region 242. Similarly, the three rotor flanges of rearward end unit 300 produce an armature core region 342. On close inspection it is seen that the actual shapes of a number of rotor and stators elements of the basic and improved embodiments are slightly different. For example, cross-sectional views of the bases of elements 116 (plus 216 and 3161 of FIG. 14 are different from the bases of the elements 16 of FIG. 1. These (plus others) are minor structural changes permissible within the overall machine I
I
designs contemplated. Other than the one exception mentioned above, the magnetic properties of the elements of both the basic and the improved embodiments are the same. On a unit by unit basis, the operating principles of the central lit 100 and end units 200 and 300 are identical to those previously described in connection with the basic embodiment of FIGS. 1-12. This is so with respect to operations as both a Gcmmutatorless lo motor and as a c~m~utatorless DC generator. however, when the three units are positioned in tandem on a common shaft within a common housing, significantly improved performance in all operating modes is realized. This is primarily due to the more effective magnetic circuit which now links the three machine units together. Whereas the basic embodiment included air gaps between the rotor bosses (elements 38' and 38") and the end yokes (elements 26F and 26R) as part of the magnetic flux paths (all as shown in FIG. 11), to present improved embodiment has no such lousy gaps. Instead, the armature core regions 242 and 342 do not extend far enough along the shaft 118 to mate with the end yokes 402F and 402R, thereby producing an effective break in the mug-netic circuit path at regions 406F and 406R. The two end machine units 200 and 300 therefore experience the overall machine flux paths as now described.
Referring to FIG. 15, there it shown half of a simplified magnetic circuit and the resulting flux paths of the improved embo-dominate of the DC machine 400. To emphasize the magnetic circuit paths of interest, a number of element designations have been omitted from this drawing, but it is to be understood that FIG. 15 represents the same eight-section, three-unit DC machine of FIG. 14.
In operation, the field core winding 154 of the central unit 100 is energized so as to produce mmf directed radially inward, giving rise to the inwardly directed central magnetic flux, indicated by the arrows - C . The field core windings 254 and 354 are ever-gibed so as to produce mums directed radially outward giving rise to the outwardly directed magnetic flux paths indicated by the flux arrows - I for the forward end unit 200, and I - the rear-ward end unit 300. The forward end unit flux arrow - Foe is .-,, shown in FIG. 15 as directed upwards through the stators core region 256, and thereafter to the rearward (towards thy right in the cylindrical yoke 124. The rearward end unit flux arrow I
is shown as also directed upwards through the stators core region 356, and thereafter pharaoh do (towards the Lotte in the cylindrical yoke 124. Due to the magnetic circuit breaks at 406~ and 406R and the nonmagnetic materials of the end flanges 402F and 402R, the resulting overall flux paths are distributed as shown in two air-cuter paths. The forward flux - I passes via its stators core region 256 and then joins with the central flux - C in a clockwise fashion; and subsequently passes back through its aroma-lure core region 242 thereby completing the magnetic circuit.
Similarly, the rearward flux I - passes via its stators core region 356 and also joins with the central flux - I , but in a counterclockwise fashion; and subsequently pauses back through its armature core region 342 to complete its magnetic circuit.
Preferably, this two-looped magnetic circuit is arranged such that the forward and rearward end units are of the same magnetic sizes, and the sum of the two equals the magnetic size of the central unit, so that the two end units share equally the magnetic flux handled by the central unit. Clearly, however, other relative sizes may also be used between the three machine units as required to meet varying operating requirements of the overall DC machine 400.
Examination of the flux directions in the two end units -US in the rotor flanges; air gaps; stators flanges; stators cores;
and pole cores - reveals that the flux direction-in all of these are reversed from those in the corresponding portions of the central unit. So, while the central unit 100 functions identically to that of the basic embodiment the two end units function the same but with opposite polarity/senses. In effect then, the improved embodiment has merely distributed its active portions in a more advantageous manner, and thereby has eliminated the magnetic circuit path losses by fully utilizing all major legs of the flux path.
to I
Operation of the ccmmutatorle~s DC machine 400 as a tandem configured motor is now described with reference to PIGS. 16-19;
plus brief references to selected fiches associated with the basic embodiment. FIG. 16 shows a perspective drawling of a composite aroma-lure winding arrangement 408 hazing eye following components four armature winding elements I 90, 180, and 360 9 circus-ferentially spaced around the rotor flanges; three machine units, forward, central and rearward; and a total of eleven-sections, distributed as three sections each for the two end units and five-sections for the central unit. Expressed in terms of previously used designations, the composite armature winding assembly 408 con-sits of at least three (one per unit) complete armature winding arrangements of the type shown in FIG. 7. Expressed quantitatively, the composite may be described as a "4x3/5/3." The four armature winding elements for the forward unit 200 are designated as 232(0 , 232(909, 232(180 I; and 232(270 - and are shown to be connected in parallel and terminated on slip rings 230P and 230R. The dusk nations of the armature winding elements of the central unit 100 and rearward unit 300 (designations not shown to eliminate drawing clutter) are similarly implied. The mature winding elements for the machine units 100 and 300 are shown as terminated in their respective slip ring pairs of FRY and FRY. Several aspects of this composite armature winding æ rangement 408 are illustrative only. Firstly, the number of armature winding elements per unit are shown as four, but any number may actually be employed depending upon. design criteria. Secondly, the number of sections are shown as eleven - distributed as 3/5/3 over the three units -but any number may actually be employed, also depending on design criteria. However, for the tandem principle to ye optimized, at least two machine units are required; and in a preferred embody-mint, three are æ ranged in tandem as shown.
FIG. 17 shows a simplified electrical schematic of the equiva-lent composite armature winding arrangement of FIG 16 operating as a motor. Brief review of thy description ox motor operation for the basic embodiment associated with F~CS. 7 and mull serve to facile-late the present description. As before, torque is produced only in the radial portions of each armature winding element again depicted as a pair of adjacent circles " Ox-"). A pair of such torque producers are designated as en and go for the second from left section of the armature winding element 132(0 if. the central unit 100. Thus, FIG. 17 shows an array of 44 pairs of torque producers grouped together as 3x4=12 for each of the end machine units, and 4x5=20 for the central unit 100.
FIG. AYE and 18B show simplified electrical schematics of a It composite stators field core winding 410 suitable for use with the improved DC machine of FIG. 14. Four identical sets of field windings 54* are confected in series (illustratively) and are energized by a DC source by a pair of terminals " " and "En".
Each of the four windings 54* in turn comprise a field core winding for each of the three machine units, wound in the proper sense so as to produce the flux patterns of FIG. 18B. By brief reference to the flux patterns of FIG. 15, recall that the required mmf's are:
radially outward for the forward and rearward end units 200 and 300 shown by the - F* and I - flux arrows, and radially inward for the central unit lQ0, shown by thy - I flux arrow.
The number of individual field core windings used on each pole core (in this case four), and the manner of interconnecting the windings (in this case all in series are factors which are determined by design convenience and requirements. Thus, the total number of field core windings (a total of twelve - four per machine unit times three units) and various series/parallel interconnection schemes are considered design choices; the primary criteria being the production of properly oriented flux of the proper magnitude in the air gaps between the spaced apart rotor and stators flanges.
FIG. 19 provide a visual summary of the primary operating parameters of the DC machine 400 while it is functioning as a tandem commutator less DC motor. Armature current is applied to the three machine units by a number of molar current arrow I
as follows: current into the forward end unit 200 via slip ring 35 230R, out via slip ring 230F; into the central unit 100 via the
Technical Field The present invention relates generally -to commutator less DC
machines of the axial air gap type which readily function as either DC motors or DC generators. Specifically, the present invention relates to a DC machine having a plurality of disk-like stators elements and one or more interleaved disk-like rotor elements adapted to produce axial magnetic flux in the air gaps between their adjacent planar surfaces, and employing umquely configured, radially oriented armature conductor winding elen~nts rotatable in the air gaps to produce the desired electromechanical transducer actions. Both a basic embodiment, and an improved embodiment comprising a number of basic units in tandem are disk closed.
Background Art Both ccmmutatorless rotary machines and axial air gap rotary machines are well known in the electrical engineering art, and have been the subject of much study and development over the years.
In their most basic forms, these two features are often found in machine embodiments wherein thy magnetic flux passes in the same direction from one member to the other over the whole of a single axial air gap area, and are designated as cyclic, or alternatively as homopolar machines While the present invention goes very far beyond the basic cyclic approach and represents an entirely new family of DC machines, it is of some interest to briefly describe prior art machines exhibiting the commutator less and axial field features.
US. Patent 1,465,251 to Broluska et at discloses an early (1920) commutator less DC machine having a plurality or inter-leaved stators and rotor disks wherein radially oriented armature conductors are immersed in axially directed magnetic fluxes to produce either motor or generator action The design however, employs a totally unidirectional magnetic flux which is customary and conventional. This purely unidirectional field approach, unfortunately calls for the segmentation of the armature conductors, which in turn gives rise to the need for a set of collector rings and rollers which engage the outer circumferences of the roller disks. The technical necessity for the collector ring structure is well documented, and a rigorous presentation of the phenomenon involved may be found in the description of the "Multi-Spoke Wheel" generator on pages 57-69 of the text "Flux Linkages and Electromagnetic Induction"
by LO Boyle. (Dover Publications, New York, 1964).
More recent prier art homopolar machines are exemplified by US. patents 3,743,874 to Shabbier and 3,699,370 to Colloidal.
Additional prior art approaches in the area of commutator less and/or axial field machines are disclosed in US. patents 3,169,204 to Myers et at; 4,082,971 to Mohawk et at; 4,187,441 to Only; and in an IBM TUB authored by C. Dung, dated March 10, 1981.
Summary Of The Invention __ It is therefore a primary object of the present invention to provide an improved commutator less DC machine which may readily function as either a DC motor or a DC generator.
Another object of the present invention is to provide a DC machine which will be largely devoid of the design limitations and operational problems associated with the use of conunutation devices of all types.
, ,=~" I, ,, .
A further object of the present invention is to provide a basic commutator less DC motor having axially oriented magnetic flux between Lnterlea~ed stout and rotor disks, wherein the rotor disks carry radially oriented armature conductors which are uniquely interconnected and terminated at a pair of slip rings; and wherein the magnetic flux incident upon the two planar surfaces of any one rotor so are oppositely directed thereby producing net torques which are directly additive resulting in heretofore unrealized superior DC motor performance.
A yet further object of the present invention is to provide a basic commutator less DC generator having axially oriented magnetic flux between interleaved stators and rotor disks, wherein the rotor disks carry radially oriented armature conductors which are uniquely interconnected and terminated at a pair of slip rings; and wherein the magnetic flux incident upon the two planar surfaces of any one rotor disk are oppositely directed thereby producing ems which are directly additive resulting in hereto-fore unrealized superior DC generator performance.
A still further object of the present invention is to pro-vise an improved co~mutatorless DC machine wherein the advantages of the basic DC motor and basic DC generator outlined above are achieved by combining a number of the basic unit together in tandem.
By means of a number of illustrative and preferred basic and improved embodiments, the present disclosure teaches the broad principles of a DC machine having axially oriented magnetic flux between interleaved Syria and rotor disks herein the rotor disks carry radially oriented armature conductors which are uniquely it reconnected and terminated at a pair of slip rings. The mug-netic flux incident upon the two planar surfaces of any one rotor disk are oppositely directed thereby producing ems or torques, which are additive resulting in heretofore unrealized electromagnetic transducer actions.
Brief Description s Additional objects and advantages of toe invention will become apparent to those skilled in the art as the description proceeds with reference to the accompanying drawings wherein:
FIG. 1 is half of a vertical cxoss-section through a basic embodiment of a commutator less DC machine according to top present invention;
FIG. 2 is a detailed vertical cross-section of the rotor assembly shown in FIG. l;
FIG. PA and 3B snow side and end views, respectively, of a typical rotor flange;
FIG. 4 is a detailed vertical cross-section of the stators assembly shown in FIG. l;
FIGS. PA and 5B show side and end views, respectively, of an illustrative plain type stators flange;
FIGS. PA and ÇB show side and end views, respectively, of a typical core type stators flange FIG. 7 is a highly schematic perspective drawing ox a complete armature winding arrangement or a four-windinq-element, three-section DC machine according to the present invention;
FIG. R it a simplifies electrical equivalent circuit cores-pounding to the complete armature winding arrangement of FIG. 7 when used as a DC generator;
FIG. 9 is a simplified electrical equivalent circuit of a complete armature winding arrangement for an eight-winding-element, seven-section DC machine when used as a DC Myra FIG. 10 is a simplified electrical equivalent circuit of : a typical four winding stators field arrangement;
FOG. 11 shows typical magnetic circuits and flux paths of the basic embodiment of FIG. 1, in highly schematic form;
FIGS. 12 and 13 show enlarged portions from FIG. 11) of typical magnetic circuits and flux paths in Fleming's Rules interaction regions for, respectively, operation as DC motors, and as DC generators;
4'7 FIG. 14 is a vertical-cross section through an improved em-bodiment of a commutator less DC machine according is the present invention;
FIG. 15 shows typical magnetic circuits and toe resulting flux paths of the improved embodiment of FIG. 14, in highly schematic form;
FIG. 16 is a perspective drawing of a composite armature winding arrangement for a four-winding-element,eleven-section, three machine unit configuration corresponding to the improved embodiment of FIG. 14;
PIG. 17 is a simplified electrical motor equivalent circuit corresponding to PIG. 16, showing the array of torque producing means;
FIGS. AYE and 18B show a simplified electrical equivalent circuit of a typical four-winding, three machine unit stators field arrangement;
FIG. 19 shows operating polarities/senses of a tandem DC
machine while functioning as a commutator less DC motor;
FIG. 20 is a simplified electrical generator equivalent circuit corresponding to FIG. 16, showing the array of voltage producing means; and FIG. 21 shows operating polarities/senses of a tandem DC
machine while functioning as a co~mutatorless DC generator.
Detailed Description of the Preferred Embodiments A Basic Embodiment referring first to FIG. 1, there is shown a basic embodiment of a commutator less DC machine according to the present m mention.
FIG. 1 shows half of a vertical cross-section through a multiple disk, simply configured DC machine 10. As a brief introduction, an overall DC machine 10 is shown as comprising two major sub-assemblies including a multiple flange rotor assembly 12, rotatable mounted within a multiple mating flange stators assembly 14. The rotor assembly 12 includes a plurality of spaced apart rotor flanges 16 assembled onto a central shaft 18 which is concentric with a machine axis of rotation 20. The stators assembly 14 includes a corresponding plurality tress one) of spaced apart stators flanges 22, mounted within a hollow cylindrical yoke 24, which yoke forms part of the outer casing of the DC machine 10. A pair of circular end yokes 26F and 26R are affixed to the front and rear ends respectively of the cylindrical yoke 24 to form an enclosed compar~ent. The ends of the central shaft 18 pass through the end yokes 25F and 25R via circular openings 28F and 28R, respect-lively, and the shaft ends ye suitably retained and fitted with bearings snot shown) by well-known and conventional means. A pair of slip rings 30F and OR are concentrically affixed on alternate ends of the central shaft 18 and serve as the electrical input/output terminals for a plurality of armature wind in elements distributed over the rotor flanges. A typical armature winding element 32 is shown in cross-section as being terminated at its forward end to the slip ring 30F via a contact 34, and at its rearward end to the slip ring 30R via a contact 36. The armature winding element 32 is con-figured as a discreet electrical wire-like conductor, shaped to follow the outer contours of the plurality of rotor flanges, and appears in cross-section as a continuous and fairly regular serpentine path confined to a particular radial plane, as is detailed below.
I '7 The structure and functions of each of the above elements, as well as additional elements, are described in more detail herein below. It is worthy of note that thy! elements outlined above are applicable to operation of the DC machine 10 as either a commute-topless DC motor or as a commutator less direct DC generator. The term "direct DC" denotes that as a DC generator, the output voltage is produced as a continuous unidirectional output and does not require commutator action for rectification into DC.
Referring now to FIG. 2, there is shown a detailed vertical cross-section of the rotor assembly 12 of FIG. 1. In the basic embodiment of FIG. 1, a seven-section DC machine is shown, the seYen-sectio~ rotor assembly depicted corresponds to that embody mint. The rotor assembly 12 is pictured as comprising a plurality of rotor flanges 16 longitudinally stacked along the central shaft 18. Reference to FIGS. PA and 3B show each of the flanges 16 to be generally disk shaped, and to haze a thickness in the axial (or longitudinal direction at its outer periphery of "if". The flanges 16 further have a rim boss 38 at their inner periphery, and a centrally located opening 40 to admit toe central shaft 18. The rim boss 38 has an axial extent slightly larger than tub tycoons "t " of the flange, and a radial dimension "rub" very much less than the radial dimension "or" of the flange The flanges 16 are made of material having predetermined desired magnetic properties and may illustratively be of forged or cast steel. When assembled as a seven-section embodiment as shown, the seven individual flange 16 (plus front and rear magnetic end pieces 38l and 38") create an armature core region 42 by virtue of the increased mass of mug-netic material provided by the thickened rim kisses and end pieces being longitudinally stacked. Thy armature core region 42 (India-acted generally by the multi headed arrow symbol of FIG. I so formed functions similarly to the armature core of a conventional DC machine. The central shaft 18 may be made of steel suitable for supporting the various rotor components during their high speed rotation operation, and the entire assembly may be fastened together by conventional means.
A wide variety of complete armature winding arrangements may be used in conjunction with the rotor assembly of FIG. 2 depending on the basic use to which the machine is being put (i.e., motor or generator); and further depending on the particular electrical and mechanical characteristics (i.e., electrical power/torque/speed) which it is desired that the machine is to exhibit. In the embodiment of FIG. 2, two armature winding elements are shown. These are winding elements 32 and 32', both of which are identical and contain a to-tat of seven contoured portions, corresponding to the number of rotor flanges of the embodiment. Only the winding element 32 will be described, it being understood that the winding element 32' (plus other winding elements equally spaced circumferential around the rotor flanges - not shown) will be identical. Basically, the winding element 32 is a count m use electrical conductor, such as a length of copper wire, formed into a serpentine contour to fit along the surfaces of each of the stack Go rotor flanges in a rotor assembly. For purposes of clarity, the winding elements 32 and 32' are shown as affixed on the outer surfaces of the flanges. Winding elements 32 and 32' ye confined to a single plane containing thy axis of rotation 20, around which axis the plane (and the two winding elements rotate. The plane containing the wincing element 32 is bounded at its radially inwards extremity (lower edge as shown) by - a tine parallel to the axis 20, and the plane containing the winding element 32' is bounded at its radially inwards extremity (upper edge as shown) by a line parallel to the axis 20. In an alternate embo-Dante, the winding elements may be affixed into shallow slots (not shown) formed into the flat side surfaces of the rotor flanges. Each extremity of the winding element 32 is connected to its adjacent slip ring for electrical contact. The slip ring 30F is mounted around the 3Q magnetic end piece 38' and insulated from it (concentrically with the rotational axis 20), and connects with the winding 32 at the contact point 34. Slip ring CRY is similarly insultingly mounted around the magnetic end piece 38" and connects with the winding 32 at the contact point 36.
'7 A clearer description of complete armature winding arrangements contemplated may be had with reference to the perspective drawing of FIG. 7, along with its corresponding simplified electrical equivalent circuit of FIG. 8, m addition to the aforementioned FIGS. 2, PA
and 33. FIG. 7 shows a complete armature winding arrangement for a DC machine coI~prisi~g, illustratively, a three-section rotor assembly (i.e., three rotor flanges); and also comprising, illustra-lively, four armature winding elements of the type 32 circumferen-tidally spaced at 90 intervals around the rotor flanges. The winding element designated as 32(0) corresponds nominally to the winding element designated 32 in FIG. 2; while the winding element design-ted 32tl80) corresponds nominally to the winding elements design noted 32' in PIG. 2. The winding elements 32~0 s d 32(270) which are not shown in FIG. 2, along with the 32(0) and 32(180) winding elements are all connected in electrical parallel via Lye termination of their corresponding extremities on slip rings 30F
and 30R. The number of rotor sections it shown in FIG. 7 as being three, as compared to the even section embodiment of FIG. 2, largely to provide an uncluttered illustration. In actual co~mutatorless DC machines designed according to the principles taught herein, it is contemplated that the number of rotor sections could be as few as one, or as many as several dozen or more.
In the electrical equivalent circuit of FIG. 8, which is shown for the case where the DC machine is being operated as a DC generator, it is seen that the winding element designated 32C0) comprises six independent em generators depicted as a pair of adjacent circle/
dot symbols I each circle of which corresponds to a radial portion of an armature minding element. Thus, the winding portion a-b-c-d corresponding to the first one of the three sections of winding ODE) of FIG. 7 is electrically equivalent to the two em generators designated a-h and c-d of the first one of the three sections of winding 32(0l of FIG. 8. In like manner, the two other sections of winding 32(0l, namely e-f-g-h and i-j-k-l of FIG. 7 translate into the four em generators e-f and g-h, plus i-j and k 1 of FIG. B. The remaining windings 32C90), 32(180), ~~ 7 and 32 (270), of both FIG. 7 and Fit;. 8 are similarly related. In short, a complete armature winding arrangement consists of a number of armature winding elements, each spanning from one slip ring to the other; all of the armature winding elements being in parallel between the slip rings. Conventional sets of brushes (not shown contact the slip rings, and leads Fran the bushes are brought out to the machine terTninal board for suitable external interconnections.
A further alternate embodiment of the present invention is shown by way of the simplified electrical equivalent circuit of FIG. 9.
This embodiment depicts the DC machine 10 while it is bring operated as a commutator less DC motor. By reference to a plurality of torque generating elements depicted as a pair of adjacent circles "-00-"
yin positions analogous to the em generators of FIG. I there is shown a seven section DC machine. The c~nplete armature winding arrangement comprises eight separate winding elements, each generally of the type 32, spaced 45 degrees apart. These eight windings are designated 32(0), 32(45~), . . . 32(315). Each armature winding element has a total of fourteen torque generators (seven prows) with the third pair in the 32(0) winding designated as consisting of an it part and a clue* part. As before, the individual torque generating elements are associated only with the radial portions of the armature winding elements. A fuller descrip-lion of the modes of operation of the ccmmutatorless DC Tnachine 10 as both a motor and also as a generator is provided hereinbelow.
Referring now Jo FIG. 4, there is shown half of a detailed Yen-tidal cross-section of the stators assembly 14 of FIG. 1. The assembly 14 is pictured as c~nprising a plurality of stators flanges 22 assembled within the cylindrical, longitudinal yoke 24, all of which is rapped by a pair of end yokes 26F and 26R. longitudinal bolts (not shown) may be used to align and fasten the various come pennants together in any conventional nunnery. By reference to FIGS.
PA, 5B~ PA, and 6B, in addition to FIG. 4, the stators flanges 22 art shown to be of two distinct types. These types are designated a stators core flange 22C, and a stators plain flange 22P. The plain type flange 22P of FIGS. PA and 5B is shown a generally disc-shaped, and having a thickness at its inner periphery of "t ". The plain flanges 22P further have a rip boss 44 at the outer periphery on one side, and a centrally located Gore of radius "r ". The rim boss 44 has an axial extent approximately the same as the thickness "t "
and a radial extent very much less than the dimension "us" of the flange 22P. Momentary reference to the overall DC macho of FIG.
1 shows that the central bore 46 has radius "r " slightly larger than the radial dimension "rub" of the boss 38 shown in FIG. 3B, allowing the rotor assembly 12 to rotate smoothly within the stators assembly 14.
The core type flange 22C of FIGS. PA and 6B is shown as also being generally disk-sha~ed,and having a thickness at its inner periphery of "t ". The core flange 22C also has a rim boss OR at its outer periphery on one side, and further has four radial pole core projections 50 spaced at 90 degree intervals around its air-cumference. The rim boss 48 extends over the pole core projections 50. Except for the presence of the core projections 50, the overall configurations and dimensions of the core flange 22C are the same as those of the plain flange 22P. On close assembly, these pole core projections 50 for a pole core region 52 (its extent indicated generally my the associated multiple headed arrows around which a field core winding 54 is wound. Of the four projections shown in FIG. PA, only one pole core region 52 is shown in FIG. 2. It is to be understood that the four pole core configuration shown is illustrative only, and that the actual number of poles to be used in any particular DC machine is largely established as a matter of design choice. Thus, DC machines according to the present invention may contain more or less pole core projections, and may also be of odd or even numbers.
A cylindrical stators core region 56 (its extent indicated generally by the associated multiple headed arrows is formed by the close assembly of the plain type and core toe stators flanges.
As with the pole core region 52, this g atop core region 56 is not a separate component as such, but is defined largely in terms of its function. the function of the stators core region 56 is similar aye to that of pole shoes in a conventional DC machine. Additional pieces of magnetic structure such as an end piece 57 may be included as necessary to suitably shape the magnetic circuit paths. Further, in selected alternate embodiments of the stators assembly 14, supple-Monterey plain flanges 22P* (indicated in dotted lines as slightly modified, i.e., not having significant rim bosses 44) may be in-eluded at the forward and rearward ends of the stators assembly to produce a stators flange/rotor flange interleaving arrangement wherein all rotor flanges 16 are surrounded on both of their planar sun faces my stators flanges of the types 22C and/or 22P and/or 22P*.
In the embodiment of FIG. 4, separate field coils would be mounted on each of the four pole core regions (only one shown) and the ends of each of these coils are brought out to the DC machine terminal board (not shown) for mutual and external electrical con-sections. A simplified electrical schematic of the stators field windings is shown in FIG. 10 as four identical sets of field windings 54 connected in series and brought out to a pair of terminals " "
and "En"- The particular arrangement of field windings is largely - determined by the design requirements a given machine is a responseto. The number of individual coils (such as the single field core winding 54) on each pole core and their specific winding and inter-connection pattern is dependent on the type of DC machine contem-plated. Illustrative DC machine types include separately excited, shunt excited, series excited and compound excited. Audi, field control rheostats external to the DC machine (not shown) may be employed as part of the excitation source applied to the " "/" "
terminals. While toe arrangement of field windings is a matter of design choice, it is significant to observe in the embodiment of FIG. 10 that the resulting magneto motive force (hereinafter mmf), as depicted by the arrow symbols "-I ", are unidirectional. In this case, all four "--I " are directed radially inwards to pro-dupe the desired magnetic circuit paths, as is detailed below.
Based on the structures detailed above, a description of the operating principles of the DC machine both as a DC motor and as a DC generator is now facilitated. While the rotor and stators electrical circuits are comparatively straightforward, the magnetic circuits of the present invention contrast significantly with the magnetic circuits ox the conventional DC machine, and warrant special attention. Referring now to FIG. 11, there is shown half of a typical magnetic circuit and the resulting flux paths of the basic embodiment DC machine shown in FIG. 1. To provide improved emphasis on the magnetic circuit paths of interest, a number of symbols have been omitted from this drawing, but it is to be under-stood that FIG. 11 represents the same seven-section DC machine described in connection with FIGS. 1, 2 and 4.
In operation, all of the yield coils of the DC machine are excited from a suitable DC source such that the my produced by the field coils can be made to be directed either radially inwards or radially outwards depending on the direction of the currents in the coils. The direction chosen does not matter to establish the operating principles. In the present description, all of the field coil excitations are chosen so as to produce mmf's directed radially inwards such that all of to pole cores have radially inward directed magnetic fluxes. This flu gets distributed as shown in the stators core to all the stators flanges, and takes the two major paths indicated by two sets of flu arrows - F _ and I - to axially cross the air gaps 58 between contiguous stators and rotor flange surfaces over their overlapping portions. There-after as shown by the arrows, the flux paths enter the rotor flanges; reach the armature core; and travel allele towards the front (or rear of the machine towards the encase. The flux paths then cross the two very thin air gaps between 38' and 38" to reach respectively, the end yokes 26F and 26R; whereupon thy flux travels radially outwards in the two end yokes; then turns to travel axially inward towards the pole in the longitudinal yoke 24; and finally returns to the pole core regions 52, thereby completing the magnetic circuit. Because of the symmetry of parts, there are two it symmetrical magnetic circuit paths beyond the pole cores. The for-warmly extending circular path (towards 26F) making a clockwise pat-tern indicated generally by its arrow ; and the rearwardly extending circular path (towards 26R~ making a counterclockwise pattern indicated generally by its arrows I - .
he flux in the air spaces 58 sandwiched by the rotor and stators flanges (hereinafter called the air gap or air gap flux) has the following features of importance. Firstly, the air gap fluxes are substantially all axially directed. Secondly, the air gap fluxes leave the stators flange surfaces substantially normal to the surfaces, and Roth the forwardly and rearwaxdly facing surfaces of all stators flanges act as if they are flux emitter surfaces. idly the air gap fluxes enter the rotor flange surfaces substantially normal to those surfaces, and both the forwardly and rearwardly facing surfaces of all the rotor flanges (except for the end flanges) act as if they are flux collector surfaces. As will be described below, the magnetic flux incident upon the two planar surfaces of any one rotor flange are oppositely directed - i.e., Roth fluxes are interiorly directed Gore detailed description of the magnetic circuits and flux paths is facilitated by reference to FIGS. 12 and 13 which show enlarged portions of a typical rotor/stator interaction areas extracted from FIG. 11. In both FIGS. 12 and 13, the path DEFGHI shows a typical portion of the armature winding element.
(These capital-lettered conductor paths are generally the same as those indicated in lower-case letters in FIG. 7). As seen, lengths EN and GO have radial runs, while lengths DE, FOG, and I have axially runs. It it significant to note that the interaction it linkages) of the magnetic flux with the axial Hun portions (DE, FOG, and HI) is assent, because the magnetic flu and these conductor lengths are parallel, and/or lie in fringe magnetic field regions. Over the radial run portions (i.e., EN and GO
the length of the conductor lying in the magnetic field air gap 58 has full interaction Linkages with the air gap magnetic flux, because the two are normal to each other. The above flux/conductor orientations are typical, and extend over the full run of each armature winding element. The same relationships obtain for all other winding elements in a complete armature winding arrangement Considering now operation of the DC machine 10 as a comma-tutorials DC motor, let all the field coils be excited to establish a magnetic field as shown in FIG. 12. Note that the flux path designated err - divides further into two paths in the stators flanges to enter each rotor flange from opposite directions. Thus, the rotor flange within the conductors EN and GO experiences front-to-rear directed flux from the stators flange emitter surface closest to the EN surface; and that the same rotor flange experiences rear-to-front directed flux from the stators flange emitter surface closest to the GO surface. jet the forward slip ring 30F of the machine be connected to a suitable external DC source (through a stating rheostat, not shown) positive terminal, and the rearward slip ring 30R be connected to the negative terminal. The direction of the resulting armature current is shown by motor current arrows - I . The interaction of the air gap magnetic flux with the orthogonally oriented current carrying conductor portions causes mechanical forces on the conductor. Applying Flings Left-Hand Rule (the motor rule) and looking at the machine from the rearward end of the shaft, the mechanical forces on the conductors EN and GO
are both in the clockwise direction. These forces constitute a clockwise torque T on the rotor assembly 12. This condition extends over the particular armature winding element 32, and further over the complete armature winding arrangements, for the portions of the conductors similarly disposed. All of these forces being additive, a large resultant torque is created on the rotor assembly thereby producing the desired operation as a DC motor.
on operation, the commutator less DC motor of the present invention exhibits the usual rotary device properties such as counter em, losses, and the like.
Considering operation of the DC machine 10 as a commutator less DC generator, let all the field coils again be excited to establish a magnetic field as shown in FIG. 13 identical to that of FIG. 12).
Ill the rotary shaft 18 be coupled to a prime mover to cause clock-I., I
wise rotation looking from the rearward end of the DC machine.
Consider the interaction of the air gap flux as before with the now rotating active armature conductor portions EN and GO. Applying Fleming's Right Rand Rule (the generator rule the conductors experience dynamically induced ems, the directions of which are from H to G and from F to E as shown by the induced current arrows I in FIX. 13. These ems are directly additive in thy winding element. This condition extends over the particular armature winding element 32 and for the complete armature winding element arrangements, for the conductors similarity disposed. All other portions of armature conductors disposed substantially differently from EN and GO do not produce any induced ems. Thus the DC machine 10 operates as a DC generator and produces the resultant em between the two slip rings, the onward slip ring attaining positive polarity, and the rearward slip ring attaining negative polarity. The DC
machine functioning either as a motor or as a generator can be loaded as in conventional DC machines, and control similar to those used in conventional DC machines may be incorporated into it. Further, the DC machine can be built for different types of excitation to obtain different characteristics as in conventional DC machines.
In summary, it is noted that basic commutator less DC machines acting either as motors or as generators may be realized using the teachings of the present invention, which simultaneously exhibit the following desirable properties. Commutators of all types are specifically absent thereby completely eliminating the full range of electrical problems they present, and further eliminating the design limitations they conventionally impose on rotating machines. Direct current exists in all of the armature winding conductors, and slip rings only are used as electrical inputs or outputs from the machine. Thy stacking of any number of separate disk (both rotor and stators sections along with the straightforward armature winding arrangements, permits the realization of commutator less DC machines for operation at almost literally any voltage or current desired.
An Improved Embodiment Referring now to FIG. 14, there is show an improved embo-dominate of a commutator less DC machine according to the present invention. FIG. 14 shows half of a vertical cross-section through a multiple disc, tandem configured, commutator less DC machine 400.
Brief reference to FIG. 1 shows that the tandem configuration of FIG. 14 contains largely the same structural elements as the simply configured (basic embodiment of FIG. 1. Thus, the structural elements of FIG. 14 which perform substantially the same functions as those of FIG. 1 are correspondingly numbered (with differing prefixes) as an aid to clarity.
Briefly, the improved DC machine 400 is shown as comprising three rotor/stator units in tandem - designated as a central machine unit 100, a forward end machine unit 200, and a rearward end machine unit 300. Taken by to selves, each of the three tandem units functions generally the same as the single unit of the basic embo-dominate. However, the addition of the two end units produces new and highly useful operating modes which give rise to a marked imp provement in machine operation as is described below. While correspondingly numbered, the various structural elements are designated by differing leading digits which designate their distinct positions within the overall DC machine 400. For instance: central shaft 118 corresponds functionally to central shaft 18; and pole core region 152 of the central unit 100, plus pole core region 252 of the forward end unit 200, and pole core region 352 of the rearward end unit correspond functionally to pole core region 52. However, as will be described, end flanges 402F and 402R do not correspond to end yokes 26~ and 26R.
In FIG. 14, a hollow cylindrical yoke 124 houses stators asset-bites 114, 214, and 314 which are functionally associated with the central, forward, and rearward machine units respectively. Each of these assemblies comprises spaced apart stators flanges 122, 222 and 322, which are shaped and assembled to create pole core regions 152, 252, and 352, as well as stators core regions 156, 256 and 356 - when I
energized by their respective field core windings 154, 254 and 354.
A pair of circular nonmagnetic end flanges 402F and 402R are affixed to the forward and rearward ends respectively of the cylindrical yoke 124 to form an enclosed compartment. me ends of the central shaft 118 pass through the end flanges 402F and 402R, and are suitably no-twined and fitted with bearings snot shown) m the regions 404F and 404R by well-known and conventional means.
The central shaft 118 (which is concentric with a machine axis of rotation 120~ carries three flanged rotor assemblies 112, 212, and 312, which are functionally associated with their cores-pondingly positioned central forward and rearward machine unit asset-bites. Each of these rotor assemblies comprises spaced apart rotor flanges 116, 216 and 316, on which are formed armature winding elements 132, 232, and 332 respectively. Each rotor assembly further comprises a concentric pair of slip rings FRY, 230F/
230R and FRY. As before, these armature winding elements are shown in cross-section, and each is terminated at its forward and rearward ends to its correspondingly lettered slip ring.
(i.e., the forward end of armature winding element 132 is terminated on slip ring 13aF, and the rearward end of armature winding element 132 is terminated on slip ring 130R; similarly for armature winding elements 232 and 332.
In the improved embodiment of FIG. 14, the central unit 100 is shown as having five illustratively) longitudinally stacked rotor flanges of thy type 116 which produce an armature core region 142, while the forward end unit 200 is shown as hazing three (illustratively) longitudinally stacked rotor flanges which produce an armature core region 242. Similarly, the three rotor flanges of rearward end unit 300 produce an armature core region 342. On close inspection it is seen that the actual shapes of a number of rotor and stators elements of the basic and improved embodiments are slightly different. For example, cross-sectional views of the bases of elements 116 (plus 216 and 3161 of FIG. 14 are different from the bases of the elements 16 of FIG. 1. These (plus others) are minor structural changes permissible within the overall machine I
I
designs contemplated. Other than the one exception mentioned above, the magnetic properties of the elements of both the basic and the improved embodiments are the same. On a unit by unit basis, the operating principles of the central lit 100 and end units 200 and 300 are identical to those previously described in connection with the basic embodiment of FIGS. 1-12. This is so with respect to operations as both a Gcmmutatorless lo motor and as a c~m~utatorless DC generator. however, when the three units are positioned in tandem on a common shaft within a common housing, significantly improved performance in all operating modes is realized. This is primarily due to the more effective magnetic circuit which now links the three machine units together. Whereas the basic embodiment included air gaps between the rotor bosses (elements 38' and 38") and the end yokes (elements 26F and 26R) as part of the magnetic flux paths (all as shown in FIG. 11), to present improved embodiment has no such lousy gaps. Instead, the armature core regions 242 and 342 do not extend far enough along the shaft 118 to mate with the end yokes 402F and 402R, thereby producing an effective break in the mug-netic circuit path at regions 406F and 406R. The two end machine units 200 and 300 therefore experience the overall machine flux paths as now described.
Referring to FIG. 15, there it shown half of a simplified magnetic circuit and the resulting flux paths of the improved embo-dominate of the DC machine 400. To emphasize the magnetic circuit paths of interest, a number of element designations have been omitted from this drawing, but it is to be understood that FIG. 15 represents the same eight-section, three-unit DC machine of FIG. 14.
In operation, the field core winding 154 of the central unit 100 is energized so as to produce mmf directed radially inward, giving rise to the inwardly directed central magnetic flux, indicated by the arrows - C . The field core windings 254 and 354 are ever-gibed so as to produce mums directed radially outward giving rise to the outwardly directed magnetic flux paths indicated by the flux arrows - I for the forward end unit 200, and I - the rear-ward end unit 300. The forward end unit flux arrow - Foe is .-,, shown in FIG. 15 as directed upwards through the stators core region 256, and thereafter to the rearward (towards thy right in the cylindrical yoke 124. The rearward end unit flux arrow I
is shown as also directed upwards through the stators core region 356, and thereafter pharaoh do (towards the Lotte in the cylindrical yoke 124. Due to the magnetic circuit breaks at 406~ and 406R and the nonmagnetic materials of the end flanges 402F and 402R, the resulting overall flux paths are distributed as shown in two air-cuter paths. The forward flux - I passes via its stators core region 256 and then joins with the central flux - C in a clockwise fashion; and subsequently passes back through its aroma-lure core region 242 thereby completing the magnetic circuit.
Similarly, the rearward flux I - passes via its stators core region 356 and also joins with the central flux - I , but in a counterclockwise fashion; and subsequently pauses back through its armature core region 342 to complete its magnetic circuit.
Preferably, this two-looped magnetic circuit is arranged such that the forward and rearward end units are of the same magnetic sizes, and the sum of the two equals the magnetic size of the central unit, so that the two end units share equally the magnetic flux handled by the central unit. Clearly, however, other relative sizes may also be used between the three machine units as required to meet varying operating requirements of the overall DC machine 400.
Examination of the flux directions in the two end units -US in the rotor flanges; air gaps; stators flanges; stators cores;
and pole cores - reveals that the flux direction-in all of these are reversed from those in the corresponding portions of the central unit. So, while the central unit 100 functions identically to that of the basic embodiment the two end units function the same but with opposite polarity/senses. In effect then, the improved embodiment has merely distributed its active portions in a more advantageous manner, and thereby has eliminated the magnetic circuit path losses by fully utilizing all major legs of the flux path.
to I
Operation of the ccmmutatorle~s DC machine 400 as a tandem configured motor is now described with reference to PIGS. 16-19;
plus brief references to selected fiches associated with the basic embodiment. FIG. 16 shows a perspective drawling of a composite aroma-lure winding arrangement 408 hazing eye following components four armature winding elements I 90, 180, and 360 9 circus-ferentially spaced around the rotor flanges; three machine units, forward, central and rearward; and a total of eleven-sections, distributed as three sections each for the two end units and five-sections for the central unit. Expressed in terms of previously used designations, the composite armature winding assembly 408 con-sits of at least three (one per unit) complete armature winding arrangements of the type shown in FIG. 7. Expressed quantitatively, the composite may be described as a "4x3/5/3." The four armature winding elements for the forward unit 200 are designated as 232(0 , 232(909, 232(180 I; and 232(270 - and are shown to be connected in parallel and terminated on slip rings 230P and 230R. The dusk nations of the armature winding elements of the central unit 100 and rearward unit 300 (designations not shown to eliminate drawing clutter) are similarly implied. The mature winding elements for the machine units 100 and 300 are shown as terminated in their respective slip ring pairs of FRY and FRY. Several aspects of this composite armature winding æ rangement 408 are illustrative only. Firstly, the number of armature winding elements per unit are shown as four, but any number may actually be employed depending upon. design criteria. Secondly, the number of sections are shown as eleven - distributed as 3/5/3 over the three units -but any number may actually be employed, also depending on design criteria. However, for the tandem principle to ye optimized, at least two machine units are required; and in a preferred embody-mint, three are æ ranged in tandem as shown.
FIG. 17 shows a simplified electrical schematic of the equiva-lent composite armature winding arrangement of FIG 16 operating as a motor. Brief review of thy description ox motor operation for the basic embodiment associated with F~CS. 7 and mull serve to facile-late the present description. As before, torque is produced only in the radial portions of each armature winding element again depicted as a pair of adjacent circles " Ox-"). A pair of such torque producers are designated as en and go for the second from left section of the armature winding element 132(0 if. the central unit 100. Thus, FIG. 17 shows an array of 44 pairs of torque producers grouped together as 3x4=12 for each of the end machine units, and 4x5=20 for the central unit 100.
FIG. AYE and 18B show simplified electrical schematics of a It composite stators field core winding 410 suitable for use with the improved DC machine of FIG. 14. Four identical sets of field windings 54* are confected in series (illustratively) and are energized by a DC source by a pair of terminals " " and "En".
Each of the four windings 54* in turn comprise a field core winding for each of the three machine units, wound in the proper sense so as to produce the flux patterns of FIG. 18B. By brief reference to the flux patterns of FIG. 15, recall that the required mmf's are:
radially outward for the forward and rearward end units 200 and 300 shown by the - F* and I - flux arrows, and radially inward for the central unit lQ0, shown by thy - I flux arrow.
The number of individual field core windings used on each pole core (in this case four), and the manner of interconnecting the windings (in this case all in series are factors which are determined by design convenience and requirements. Thus, the total number of field core windings (a total of twelve - four per machine unit times three units) and various series/parallel interconnection schemes are considered design choices; the primary criteria being the production of properly oriented flux of the proper magnitude in the air gaps between the spaced apart rotor and stators flanges.
FIG. 19 provide a visual summary of the primary operating parameters of the DC machine 400 while it is functioning as a tandem commutator less DC motor. Armature current is applied to the three machine units by a number of molar current arrow I
as follows: current into the forward end unit 200 via slip ring 35 230R, out via slip ring 230F; into the central unit 100 via the
-2~1-slip ring 130F and out via the slip ring 130R; and into the rearward end unit 300 via the slip ring 330R; and out via slip ring 330F.
(The motor current arrows ---O*- of FIG. 19 are functionally analogous to the motor current arrows I of FIG. 12, but of course, not necessarily of the same magnitude; and similarly for the flux arrows - I and - I ; and I - and I - .
upon applying a DC source via a pair of terminals I' Q and as shown in JIG. 17, and further upon energizing the composite field coils of FIG. AYE to produce the flux orientations as shown in FIG. 18B and FIG. 15, operation as a commutator less DC motor results.
As before, a straightforward application of Fleming's Left-Hand Rule for motors applies, and describes the action. Consider one part-cuter portion of the air gap designated as 258 as typical. In that portion of the armature winding element 232, armature current is directed radially inwards. The air gap portion of the flux - F*--vector is directed rearward left to right) giving rise to a torque (into the plane of the paper) producing clockwise rotation as viewed from the rearward end of the central shaft 118. Thus, a net torque "T" is exerted via the shaft 118 responsive to the series aiding effect of all active portions of the rotor/stator air gaps.
Operation of the commutator less DC machine 400 as a tandem con-figured generator is now described with reference to FIGS. 16, 18, 20 and 21; plus brief reference to selected figures associated with the basic embodiment. FIG. 20 shows a simplified electrical schematic of the composite armature winding arrangement of FIG. 16 operating as a generator. Brief reference to the description associated with FIGS. 7 and 9 will facilitate the present description. As before, voltage is induced only in the radial portions of each armature wading element (again depicted as a pair of adjacent circle/dot symbols "-OX-"). A pair of such em generators are designated as "e-f"
and "g h" for the second from left section in the central unit 100. Thus, FIG. 20 shows an array of 44 pairs of em producers grouped together as twelve each for the forward and rearward end units 200 and 300, and twenty for the central unit 100.
Lo -US-FIG. 21 provides a visual Syria of the primary operating parameters of the DC machine 400 while it is functioning as a tan-dim commutator less DC generator. upon energizing the composite field coils of FIG. AYE, as for motor operation, and applying clockwise (as viewed from the machine rearward end) rotation to the shaft 118, operation as a cGmmutatorless DC generator results. A straightforward application of Fleming's Right-Hand Rule for generators applies, and describes the action. By selecting a representative portion of the air gap, designated 258 as before, we note that the air gap portion of the flux F* _ vector is directed rearward (left to right), and that the rotation I
causes the rotor flanges 216 to move clockwise (into the plane of the paper). Thus, voltage is induced in the radial portion of the armature winding element in the gap 358, giving rise to conventional currents as indicated by a number of current arrows {I* .
The net voltage produced by all active rotor~stator regions in the three tandem machine units produce generator currents as follows:
current leaves the forward end machine unit 200 from slip ring 230R; leaves the central machine unit 100 from slip ring 130F; and leaves the rearward end machine unit 300 from the slip ring 330R.
Interconnection of the outputs from the three tandem machine units to be series aiding produces a highly effective commutator less DC
generator embodying the principles of the present invention.
As with the basic embodiment, the improved DC machine lung-toning either as-a motor or as a generator can be loaded the same as conventional DC~machines; and well-known controls similar to those used in conventional DC machines may be incorporated into it. Further, both the basic and the improved DC machines can be built for different types of excitation to obtain different kirk-teristics as in conventional DC machines.
In summary, it is noted that the commutator less DC machines acting either as motors or as generator, and configured as either basic or improved embodiments, may be realized using the teachings of the present invention, which simultaneously exhibit the following desirable properties. Commutators of all types are specifically ,.
26~
absent, thereby completely eliminating the full range of electric eel problems they present, and further eliminating the design limit stations they conventionally impose on rotating machines. Direct current exists in all of the armature winding conductors, and slip rings only are used as electrical inputs or outputs from the machine.
me stacking of any number of separate disk (both rotor and stators sections, plus the use of various types of field core winding arrangements, and various tandem combinations of machine units, permits the realization of c = utatorless DC machines for operation at almost literally any voltage/current/torque/speed range desired.
Although the invention has been described in terms of basic and improved embodiments and selected preferred alternates thereof, the invention should not be deemed limited thereto, since other embodiments and modifications will readily occur to one skilled in the art. For example, while the embodiments described show the rotor structure as rotating within stationary stators structure, as is conventional; it would be merely a design choice to embody the disclosed inventive concepts into a machine wherein the stators struck lure were rotated around stationary rotor structure. Also, arranging the improved embodiment into a 4x3/5/3 configuration is merely a design choice, illustrative other choices such as 4x3/6/3 or 8xlO/20/lO
would be equally feasible. And, the present descriptions have been facilitated by assuming that the flux linkages in the non radial portions of the armature winding elements are Nero. This may not necessarily be the case for all configurations. Leakage flux from stators to rotor linking the axial run portions may in some cases produce electromagnetic results that are additive to the outputs of the machine embodiments working either as motors or as generators. It is therefore to be under-stood that the appended claims are intended to cover all such modifica-lions and variations as fall within the true spirit and scope of the invention.
(The motor current arrows ---O*- of FIG. 19 are functionally analogous to the motor current arrows I of FIG. 12, but of course, not necessarily of the same magnitude; and similarly for the flux arrows - I and - I ; and I - and I - .
upon applying a DC source via a pair of terminals I' Q and as shown in JIG. 17, and further upon energizing the composite field coils of FIG. AYE to produce the flux orientations as shown in FIG. 18B and FIG. 15, operation as a commutator less DC motor results.
As before, a straightforward application of Fleming's Left-Hand Rule for motors applies, and describes the action. Consider one part-cuter portion of the air gap designated as 258 as typical. In that portion of the armature winding element 232, armature current is directed radially inwards. The air gap portion of the flux - F*--vector is directed rearward left to right) giving rise to a torque (into the plane of the paper) producing clockwise rotation as viewed from the rearward end of the central shaft 118. Thus, a net torque "T" is exerted via the shaft 118 responsive to the series aiding effect of all active portions of the rotor/stator air gaps.
Operation of the commutator less DC machine 400 as a tandem con-figured generator is now described with reference to FIGS. 16, 18, 20 and 21; plus brief reference to selected figures associated with the basic embodiment. FIG. 20 shows a simplified electrical schematic of the composite armature winding arrangement of FIG. 16 operating as a generator. Brief reference to the description associated with FIGS. 7 and 9 will facilitate the present description. As before, voltage is induced only in the radial portions of each armature wading element (again depicted as a pair of adjacent circle/dot symbols "-OX-"). A pair of such em generators are designated as "e-f"
and "g h" for the second from left section in the central unit 100. Thus, FIG. 20 shows an array of 44 pairs of em producers grouped together as twelve each for the forward and rearward end units 200 and 300, and twenty for the central unit 100.
Lo -US-FIG. 21 provides a visual Syria of the primary operating parameters of the DC machine 400 while it is functioning as a tan-dim commutator less DC generator. upon energizing the composite field coils of FIG. AYE, as for motor operation, and applying clockwise (as viewed from the machine rearward end) rotation to the shaft 118, operation as a cGmmutatorless DC generator results. A straightforward application of Fleming's Right-Hand Rule for generators applies, and describes the action. By selecting a representative portion of the air gap, designated 258 as before, we note that the air gap portion of the flux F* _ vector is directed rearward (left to right), and that the rotation I
causes the rotor flanges 216 to move clockwise (into the plane of the paper). Thus, voltage is induced in the radial portion of the armature winding element in the gap 358, giving rise to conventional currents as indicated by a number of current arrows {I* .
The net voltage produced by all active rotor~stator regions in the three tandem machine units produce generator currents as follows:
current leaves the forward end machine unit 200 from slip ring 230R; leaves the central machine unit 100 from slip ring 130F; and leaves the rearward end machine unit 300 from the slip ring 330R.
Interconnection of the outputs from the three tandem machine units to be series aiding produces a highly effective commutator less DC
generator embodying the principles of the present invention.
As with the basic embodiment, the improved DC machine lung-toning either as-a motor or as a generator can be loaded the same as conventional DC~machines; and well-known controls similar to those used in conventional DC machines may be incorporated into it. Further, both the basic and the improved DC machines can be built for different types of excitation to obtain different kirk-teristics as in conventional DC machines.
In summary, it is noted that the commutator less DC machines acting either as motors or as generator, and configured as either basic or improved embodiments, may be realized using the teachings of the present invention, which simultaneously exhibit the following desirable properties. Commutators of all types are specifically ,.
26~
absent, thereby completely eliminating the full range of electric eel problems they present, and further eliminating the design limit stations they conventionally impose on rotating machines. Direct current exists in all of the armature winding conductors, and slip rings only are used as electrical inputs or outputs from the machine.
me stacking of any number of separate disk (both rotor and stators sections, plus the use of various types of field core winding arrangements, and various tandem combinations of machine units, permits the realization of c = utatorless DC machines for operation at almost literally any voltage/current/torque/speed range desired.
Although the invention has been described in terms of basic and improved embodiments and selected preferred alternates thereof, the invention should not be deemed limited thereto, since other embodiments and modifications will readily occur to one skilled in the art. For example, while the embodiments described show the rotor structure as rotating within stationary stators structure, as is conventional; it would be merely a design choice to embody the disclosed inventive concepts into a machine wherein the stators struck lure were rotated around stationary rotor structure. Also, arranging the improved embodiment into a 4x3/5/3 configuration is merely a design choice, illustrative other choices such as 4x3/6/3 or 8xlO/20/lO
would be equally feasible. And, the present descriptions have been facilitated by assuming that the flux linkages in the non radial portions of the armature winding elements are Nero. This may not necessarily be the case for all configurations. Leakage flux from stators to rotor linking the axial run portions may in some cases produce electromagnetic results that are additive to the outputs of the machine embodiments working either as motors or as generators. It is therefore to be under-stood that the appended claims are intended to cover all such modifica-lions and variations as fall within the true spirit and scope of the invention.
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A commutatorless DC machine having an outer housing and a shaft for rotation therein, comprising:
a) a plurality of axially spaced annular stator disks of magnetic material mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material arranged concentrically along said shaft for rotation therewith;
c) each of said at least one rotor disk positioned adjacent to at least one stator disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings mounted on said shaft; and f) whereby two of the group consisting of said unitary armature winding element, and said axially air gaps, and said rotatable shaft, may be so energized as to produce electromechanical transducer action.
a) a plurality of axially spaced annular stator disks of magnetic material mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material arranged concentrically along said shaft for rotation therewith;
c) each of said at least one rotor disk positioned adjacent to at least one stator disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings mounted on said shaft; and f) whereby two of the group consisting of said unitary armature winding element, and said axially air gaps, and said rotatable shaft, may be so energized as to produce electromechanical transducer action.
2. The commutatorless DC machine of Claim 1 configured as a DC motor and further having at least one field winding for pro-ducing a unidirectional magnetic flux in said stator disks to establish a magnetic circuit path which is substantially axially directed in said axial air gaps and further configured to establish oppositely directed magnetic fluxes upon the two opposed planar surfaces of any one rotor disk, wherein upon applying an external source of direct current to said unitary armature winding element to establish radially directed current flow and further energizing said at least one field winding to establish axially directed mag-netic flux in said air gaps, a net force is produced on said shaft so as to provide electromechanical conversion.
3. The commutatorless DC machine of Claim 1 configured as a DC generator and further having at least one field winding for producing a unidirectional magnetic flux in said stator disks to establish a magnetic circuit path which is substantially axially directed in said axial air gaps and further configured to establish oppositely directed magnetic fluxes upon the two opposed planar surfaces of any one rotor disk, wherein upon applying a source of direct current to said at least one field winding to establish axially directed magnetic flux in said air gaps, and further applying an external source of rotation to said shaft, a net direct current is produced in said armature winding so as to provide mechanical to electrical energy conversion.
4. A commutatorless DC machine having an outer housing and a shaft for rotation therein and a plurality of machine units disposed within said housing, each machine unit comprising:
a) a plurality of axially spaced annular stators disks of magnetic material mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material arranged concentrically along said shaft for rotation therewith;
c) each of said at least one rotor disk positioned adjacent to at least one stators disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings mounted on said shaft; and f) whereby two of the group consisting of said unitary armature winding element, and said axially air gaps, and said rotatable shaft, may be so energized as to produce electro-mechanical transducer action.
a) a plurality of axially spaced annular stators disks of magnetic material mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material arranged concentrically along said shaft for rotation therewith;
c) each of said at least one rotor disk positioned adjacent to at least one stators disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings mounted on said shaft; and f) whereby two of the group consisting of said unitary armature winding element, and said axially air gaps, and said rotatable shaft, may be so energized as to produce electro-mechanical transducer action.
5. The commutatorless DC machine of Claim 4 wherein the transducer actions of all of said machine units are of the same type and are combined to produce a composite transducer action greater than that of any one machine unit.
6. The commutatorless DC machine of Claim 5 having a plurality of annular rotor disks in each of said machine units, each rotor disk interleavedly positioned between a pair of stator disks and spaced therefrom to establish axial magnetic air gaps between the adjacent surfaces of said interleaved disks.
7. The commutatorless DC machine of Claim 5 further com-prising at least one field winding in each of said machine units for producing a unidirectional magnetic flux in said stator disks thereby establishing a magnetic circuit path which is substantially axially directed in said axial air gaps and configured such that magnetic fluxes incident upon the two opposed planar surfaces of any one rotor disk are oppositely directed.
8. A tandem configured commutatorless DC motor having an axial shaft journalled for rotation within an outer housing and a plurality of machine units disposed within said housing, each machine unit comprising:
a) a plurality of axially spaced annular stator disks of magnetic material fixedly mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material concentrically arranged and fixedly mounted on said shaft for rotation therewith;
c) each of said at least one rotor disk positioned ad-jacent to at least one stator disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings concentrically mounted on said shaft for rotation therewith;
f) at least one field winding for producing a unidirectional magnetic flux in said stator disks thereby establishing a mag-netic circuit path which is substantially axially directed in said axial air gaps and configured to direct magnetic fluxes upon the two opposed planar surfaces of any one rotor disk which are oppositely directed; and g) whereby upon applying an external source of direct current to said unitary armature winding element to establish radially directed current flow and further energizing said at least one field winding to establish axially directed magnetic flux in said air gaps, a net force is produced on said shaft so as to provide electromechanical conversion.
a) a plurality of axially spaced annular stator disks of magnetic material fixedly mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material concentrically arranged and fixedly mounted on said shaft for rotation therewith;
c) each of said at least one rotor disk positioned ad-jacent to at least one stator disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings concentrically mounted on said shaft for rotation therewith;
f) at least one field winding for producing a unidirectional magnetic flux in said stator disks thereby establishing a mag-netic circuit path which is substantially axially directed in said axial air gaps and configured to direct magnetic fluxes upon the two opposed planar surfaces of any one rotor disk which are oppositely directed; and g) whereby upon applying an external source of direct current to said unitary armature winding element to establish radially directed current flow and further energizing said at least one field winding to establish axially directed magnetic flux in said air gaps, a net force is produced on said shaft so as to provide electromechanical conversion.
9. The tandem configured DC motor of Claim 8 wherein the net forces of all of said plurality of machine units are combined to produce a composite net force greater than that of any one machine unit.
10. The tandem configured DC motor of Claim 9 having a plurality of annular rotor disks in each of said machine units, each rotor disk interleavedly positioned between a pair of stator disks and spaced therefrom to establish axial magnetic air gaps between the adjacent surfaces of said interleaved disks.
11. The tandem configured DC motor of Claim 9 having three machine units disposed as forward, central and rearward machine units, the unidirectional magnetic flux of each machine unit combining into an overall magnetic circuit flux path comprising two primary contradirectional paths including a first path having magnetic flux oriented in a first axial direction within a first portion of said housing and a second path having magnetic flux oriented in a second axial direction within a second portion of said housing such that said first path is largely confined to said forward and central machine units and carries a magnetic circuit flux path closed in a first circular direction, and said second path is largely confined to said rearward and central machine units and carries a magnetic flux path closed in a second circular direction opposite to said first circular direction.
12. A tandem configured commutatorless DC generator having an axial shaft journalled for rotation within an outer housing and a plurality of machine units disposed within said housing, each machine unit comprising:
a) a plurality of axially spaced annular stator disks of magnetic material fixedly mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material concentrically arranged and fixedly mounted on said shaft for rotation therewith;
c) each of said at least one rotor disk positioned adjacent to at least one stator disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings concentrically mounted on said shaft for rotation therewith;
f) at least one field winding for producing a unidirectional magnetic flux in said stator disks to establish a magnetic cir-cuit path which is substantially axially directed in said axial air gaps and further configured to establish oppositely directed magnetic fluxes upon the two opposed planar surfaces of any one rotor disk; and g) whereby upon applying an external source of direct current to said at least one field windings to establish axially directed magnetic flux in said air gaps, and further applying an external source of rotation to said shaft, a net direct current is produced in said armature winding so as to provide mechanical to electrical energy conversion.
a) a plurality of axially spaced annular stator disks of magnetic material fixedly mounted within said housing;
b) at least one axially spaced annular rotor disk of magnetic material concentrically arranged and fixedly mounted on said shaft for rotation therewith;
c) each of said at least one rotor disk positioned adjacent to at least one stator disk and interleaved therewith to establish axial air gaps between the adjacent surfaces of said interleaved disks;
d) a plurality of radially disposed electrical conductors affixed to each of said at least one rotor disk so as to be rotatable in said air gaps, and serially interconnected via a serpentine path into a unitary armature winding element having two ends;
e) each of said ends connected to one of a pair of slip rings concentrically mounted on said shaft for rotation therewith;
f) at least one field winding for producing a unidirectional magnetic flux in said stator disks to establish a magnetic cir-cuit path which is substantially axially directed in said axial air gaps and further configured to establish oppositely directed magnetic fluxes upon the two opposed planar surfaces of any one rotor disk; and g) whereby upon applying an external source of direct current to said at least one field windings to establish axially directed magnetic flux in said air gaps, and further applying an external source of rotation to said shaft, a net direct current is produced in said armature winding so as to provide mechanical to electrical energy conversion.
13. The tandem configured DC generator of Claim 12 wherein the net direct voltage of all of said plurality of machine units are combined to produce a composite net direct voltage greater than that of any one machine unit.
14. The tandem configured DC generator of Claim 13 having a plurality of annular rotor disks in each of said machine units, each rotor disk interleavedly positioned between a pair of stator disks and spaced therefrom to establish axial magnetic air gaps between the adjacent surfaces of said interleaved disks.
15. The tandem configured DC generator of Claim 13 having three machine units disposed as forward, central and rearward units, the unidirectional magnetic flux of each machine unit combining into an overall magnetic circuit flux path comprising a first path having magnetic flux oriented in a first axial direction within a first portion of said housing and a second path having magnetic flux oriented in a second axial direction within a second portion of said housing such that said first path is largely confined to said forward and central machine units and is closed in a first circular direction, and said second path is largely con-fined to said rearward and central machine units and is closed in a second circular direction opposite to said first circular direction.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US593,199 | 1984-03-27 | ||
| US06/593,199 US4514653A (en) | 1982-04-20 | 1984-03-27 | Commutatorless direct current machine |
| US69481085A | 1985-01-25 | 1985-01-25 | |
| US694,810 | 1985-01-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1211147A true CA1211147A (en) | 1986-09-09 |
Family
ID=27081646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000477289A Expired CA1211147A (en) | 1984-03-27 | 1985-03-22 | Tandem commutatorless dc machine |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0174996A1 (en) |
| AU (1) | AU4153885A (en) |
| CA (1) | CA1211147A (en) |
| IN (1) | IN164111B (en) |
| WO (1) | WO1985004533A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4712033A (en) * | 1986-12-22 | 1987-12-08 | General Electric Company | Acyclic generator with liquid metal current collectors having circulating current barriers |
| GB8916782D0 (en) * | 1989-07-21 | 1989-09-06 | Nycomed As | Compositions |
| GB2410064A (en) * | 2004-01-19 | 2005-07-20 | Ivan Mendez | A vertical axis wind powered generator |
| LT5370B (en) | 2004-10-29 | 2006-10-25 | Kauno technologijos universitetas | Method and device for generating thermoelectric energy |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1465251A (en) * | 1920-07-06 | 1923-08-21 | Cyril Cailliau | Electric machine |
| GB1037416A (en) * | 1962-05-09 | 1966-07-27 | Geoffrey Richard Polgreen | Improvements in and relating to homopolar dynamo-electric machines |
| US3585398A (en) * | 1969-10-13 | 1971-06-15 | Gen Electric | Brushless excitation of a steam turbine generator utilizing a driver acyclic generator |
| US3586894A (en) * | 1969-11-12 | 1971-06-22 | Lear Siegler Inc | Servomotor |
| FR2115687A5 (en) * | 1970-11-30 | 1972-07-07 | Anvar | |
| US3743874A (en) * | 1971-11-18 | 1973-07-03 | Anvar | Homopolar machines with contacts of liquid metal |
-
1985
- 1985-03-22 CA CA000477289A patent/CA1211147A/en not_active Expired
- 1985-03-25 WO PCT/US1985/000488 patent/WO1985004533A1/en unknown
- 1985-03-25 AU AU41538/85A patent/AU4153885A/en not_active Abandoned
- 1985-03-25 EP EP19850901813 patent/EP0174996A1/en not_active Withdrawn
- 1985-03-30 IN IN238/CAL/85A patent/IN164111B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1985004533A1 (en) | 1985-10-10 |
| EP0174996A1 (en) | 1986-03-26 |
| AU4153885A (en) | 1985-11-01 |
| IN164111B (en) | 1989-01-14 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |