DE2409796A1 - HOMOPOLAR DYNAMOELECTRIC MACHINE - Google Patents

Description

DlPL-ING. KLAUS NEUBECKER

Patent attorney
4 Düsseldorf 1 S chad ο w ρ I at ζ 9 2409796

. Düsseldorf, February 28, 1974

Westinghouse Electric Corporation
Pittsburgh, Pa., V. St. A.

Horopolar dynamo-electric machine

The present invention relates to homopolar dynamoelectric Machines, in particular a horopolar dynamo-electric machine having segmented magnets, in which a flud-cooled Liquid metal current collecting arrangement is used.

So far there have been many versions of homopolar motors and generators proposed and built. These included homopolar machines with segmented drums and disks, multilayered ones Drums or individual drums and discs. Conventional designs required very large magnets to accommodate the high magnetic ones To generate fluxes that chain the anchor conductors together in order to generate the necessary voltages and currents in them.

Some attempts have also been made in the past to improve performance Increase homopolar machines by using a plurality of magnetic poles along the axis of the machine

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became. Examples of such attempts can be found in U.S. Patents 1,339,772, 1,271,061, 1,327,349 and 1,327,350. It is true that documents disclose the concept of using a plurality of magnetic circuits to increase the performance of homopolar dyn araoe lek tr is more likely to raise machines, but apparently none commercially viable machine of this type has been manufactured.

With the increasing attention given to the application of superconductivity is dedicated, appears the use of superconducting windings for the provision of the in a homopolar dynamoelectric Machine required high fields interesting. Efforts are currently being made to use homopolar machines revolving disk and concentric drum that use individual superconducting magnets. Using a Single or double magnets for machines with a rotating drum armature are known. However, all of these machines use great ones Flow systems with large air gaps so that high energy excitation systems are required.

Considering the considerably higher currents as they are due to homopolar Machines are created with superconducting magnets, the old mechanical brushing process of the transmission of Electricity from a moving to a stationary body is overtaken because mechanical brushes somehow generate high current densities for one not able to cope with any appreciable length of time. Liquid metal faceplate assemblies have therefore become necessary. Liquid metal Stromsaioidel assemblies can handle high current densities, however, it excludes the liquid steel in fields of low flow

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work to reduce the magnetohydrodynamic losses in the liquid metal to keep it at an acceptable level. This means that unsaturated ferromagnetic material is in the neighborhood Stromsammeizone must be arranged to face the liquid metal protect against excessive magnetohydrodynamic losses.

An example of a single magnet construction according to the prior art Technology that works with a liquid metal current collecting arrangement, can be found in "The Engineer", 8/12/71, pp. 39/40. In all examples of this type of machine, the machine is in relation to the achieved output power is large and heavy, a high-energy excitation system is required to generate the necessary magnetic ' To provide flow, and the discharge of the liquid metal- Power collecting assembly generated insufficient heat.

A homopolar dynamo-electric machine is one in accordance with the invention

Characterized by / cylindrical jacket made of ferromagnetic material and a cylindrical core of ferromagnetic material concentric therewith and rotatable in relation to one another are mounted, one connected to the jacket, distributed at intervals over its circumference and a plurality of axially ira ratio of mutually staggered groups combined electrical conductor, a plurality of magnetic poles forming, arranged in the core excitation coils, such a magnetic pole next to each of the group of conductors is arranged, projecting current collecting rings connected to the ends of the conductors, arranged in the core Stromsainmelringkörper with with the protruding Stroms ammeiringen interacting, liquid metal for the creation of an electrical

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see connection between the current collecting rings and the current collecting ring bodies containing grooves, furthermore through channels provided in the annular bodies for the guidance of cooling fluid.

A stationary one generating a magnetic field is expedient Structure like a ferromagnetic core outside the jacket and arranged concentrically therewith. Due to the rotation of the jacket is for a relative movement between the jacket and the Core taken care of. In the inner part of the ferromagnetic core are Core grooves formed at axial intervals. Excitation coils are designed as excitation windings and are arranged in these core slots. In addition, current collecting ring bodies are arranged in the core grooves. The current collecting ring bodies are provided with grooves which cooperate with the projecting current collecting rings on the jacket. In these Grooves a liquid metal is arranged in order for the conductive connection between the projecting rings and the ring bodies care for. The channels for conducting a cooling fluid such as water are arranged in the current collecting ring bodies. Through a suitable connection the current collecting ring body can be used in the individual conductor groups The generated voltages are connected in series and thus the output voltage can be greatly increased.

Each of the excitation windings can be supplied with a current which is opposite to the current in an adjacent winding flows so that the effective flux for each of the conductors is thereby increased. In addition, the core can be produced in accordance with the Flux distribution can be used to determine the amount of ferromagnetic material used in the machine and thus weight and

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Reduce the cost of the machine.

With such a structure, the stationary and rotating parts have very thin radial dimensions, so that, as a result, a very small lightweight homopolar dynamo-electric machine can be manufactured. In addition, the structure according to the present invention allows Invention of very small air gaps between the jacket and the core, so that short flow paths and thus lower requirements surrendered to the excitement. Furthermore, the arrangement of cooling channels, which run directly through the Stromsammelringkorper, a quick and effective dissipation of the heat generated in the liquid metal and thus a practical utilization of this Construction.

The invention is illustrated below with reference to exemplary embodiments in Connection explained with the accompanying drawing. In the drawing show:

«Fig. 1 schematically shows an axial cross-sectional view of a Part of a homopolar dynamo-electric machine;

FIG. 2, on an enlarged scale, a view of a segment of the structure according to FIG. 1;

Fig. 3. schematically a partial cross-section to illustrate a possibility of arranging conductors, in which voltages generated by a machine are v / ground;

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Fig: 4 schematically shows a possibility of connecting according to " 3 arranged conductor groups;

FIG. 5 schematically shows a partial section similar to FIG. 3 to illustrate a further possibility that To arrange ladder;

FIG. 6 schematically shows a view similar to FIG. 4 for the purpose of illustration a possibility of connecting conductors arranged in accordance with FIG. 5;

7 schematically shows a possibility of connecting Current collecting elements to those generated in the conductors To connect voltages in series;

8 schematically shows a region of an excitation winding with conventional water-cooled conductors;

9 schematically shows a view of an insulated superconducting excitation winding; and

Fig. 10 schematically shows a view in which the entire excitation structure using superconducting windings is thermally insulated.

Ira individual leaves Fiy. 1 sclieiuati a tron-raelföriai ^ e horuopolar dynamo-electric machine with an inner z / lindrian ijantel 11 made of ferromagnetic ^ material recognize. Outside of this

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ferromagnetic cylindrical shell 11 is concentric therewith ain ferromagnetic core 13 is arranged. With this one The ferromagnetic core 13 is a special embodiment arranged stationary, while the ferromagnetic jacket 11 is rotatable is mounted so that the sheath and core can be moved relative to each other. It goes without saying that the Cladding 11 could be held stationary and then the core 13 could be rotated. Furthermore, the jacket 11 could be arranged outside the core 13 be, yet an effective homopolar machine would be available.

A plurality of electrical conductors 15 are distributed around the circumference of the ferromagnetic jacket 11 at intervals. This ladder 15

in

are groups offset in the axial direction / in relation to one another, arranged along the outer part of the jacket 11. (In the axial cross-section according to FIG. 1, each of the conductor groups only has one of the conductors 15 can be seen.)

In the inner part of the ferromagnetic core are axial Field windings 17 spaced apart from one another. The electrical conductors 15 extend between adjacent pairs Excitation windings 17. As indicated by the dashed lines 19, which represent the course of the magnetic flux ■ opposite seals of current flow in adjacent windings used to generate magnetic fluxes that have opposite directions of flow. In this way each of the cuts Conductor 15 the flux of two adjacent windings, so that the voltage induced therein essentially doubles

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moves. In other words, by using opposite directions of current flow in adjacent excitation windings, the flow acting on a single conductor 15 is the same (with respect to the polarity of the induced voltage). Thus, not only is the flux used increased _T, but also both conductor ends adjacent to an excitation winding have the same polarity, as indicated in FIG. 1 with the corresponding polarity symbols.

It can also be seen that the ferromagnetic core 13 is the course of the flux generated by the excitation winding 17 is adapted. In this way there is a considerable saving ferromagnetic material, with the result that the machine is lighter and gets cheaper.

The structure of this machine can be described more precisely with reference to the enlarged illustration of a segment according to FIG to understand. As can be seen therefrom, core grooves 21 are provided in the core 13. The excitation windings 17 are at the bottom of the core grooves 21 arranged. In the remaining area of the core grooves 21 Stromsammelringkorper 23 are arranged, which from a suitable Consist of conductor material. In each core groove 21 (with the exception of the core grooves at both ends of the machine) there are at least two current collecting ring bodies 23 housed. As illustrated with the embodiment of FIG. 2, more than the two basic current collecting rings 23 can be used. In this particular embodiment, there are a total of four current collecting ring bodies 23 housed in each core groove 21.

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The current collecting ring body 23 are from each other and opposite the Core grooves 21 isolated by a suitable insulating material 25.

A groove 27 is formed in each of the current collecting ring bodies 23. These grooves have an annular course and extend over the entire inner circumference of the current collecting ring body 23 Grooves 27 are designed so that they interact (mesh) with raised or protruding current collecting rings 29 in a suitable manner. that are electrically connected to the conductors 15 and serve to transmit the current from a group of these conductors to accommodate the current collecting ring body 23. As shown in Figure 2, at each end of a group of conductors 15 are two protruding ones Stromsammeiringe 29 arranged. This is due to the fact that the conductors of a group of conductors 15 are alternately connected to one or the other of the projecting current collecting rings 29. Thus, one group of conductors is with one of the protruding current collecting rings (at each end) and another group of conductors with the other protruding Stromsammeiring 29 connected. Through suitable Connection of the current collecting ring body 23, the voltages generated in the individual groups with the conductors 15 can be connected in series to increase the amplitude of the output voltage.

Fig. 3-6 show two possibilities for the arrangement of the conductors 15 in the jacket 11 and the connection of groups with these conductors, so that the voltages generated are connected in series in the desired manner. With Fig. 3 it is shown how individual conductors 15 are embedded in shell grooves 31 which are formed in the outer part of the shell 11. The jacket grooves 31 are spaced apart

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distributed over the circumference of the jacket 11, the embedded therein Conductor 15 insulated in a suitable manner from the grooves

In Fig. 4 three protruding Stromsammlungiringe 29 are with A, B and C designated. These protruding rings correspond to the grooves of FIG. 3 which are provided with the same letters A, B and C, respectively Designations of FIG. 3 repeat periodically, so that every third groove is an "A" groove, every "A" groove is followed by a "B" groove, etc. The conductors in all of the "A" slots are electrically connected to one another and connected to the projecting Stromsansnelringe 29, the are also designated by "A". Everyone is in the same way Conductor 15 connected in the grooves marked "B" to the projecting StromsolleIring 29, which bears the designation "B", and the same applies accordingly to the conductors marked "C". In a structure of this type, instead of the two with Fig. 2 reproduced current collecting ring body 23 three such Current collecting body corresponding to the protruding current collecting ring Aj. B and C may be provided. By connecting the the individual ends of the electrical conductor 15 associated ring body could be the output voltage compared to that in a single Head 15 occurring can be practically tripled.

5 shows a further possibility of arranging conductors in the jacket 11. In this case, there are three conductors in each jacket groove 31 have been stacked on top of each other. The three conductors in each jacket groove 31 are again labeled A, B and C, respectively, and are more suitable Way separated from each other by insulating material. As in the case of the

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3 and 4, FIG. 6 shows how the conductors of FIG. 5 can be connected in groups to the projecting current collecting rings 29, which are designated in the same way by A _f B and C, respectively. As in the case of the embodiment according to FIGS. 3 and 4, the output voltage of the machine using the structure according to FIGS. 5 and 6 is practically tripled with respect to that generated in a single conductor 15.

As can be seen from FIG. 2, the current absorbed by the current collecting rings 29 is passed through a liquid metal conductor 33 to the Strora collecting ring bodies 23 passed. In the grooves 27 there is liquid metal 33 arranged, which is suitably adjacent to the projecting Stromsammeiringe 29 and the inner part of the grooves 27 to an electrically conductive path between the protruding current collecting rings 29 and the current collecting ring bodies 23 to form. The liquid metal 33 is of a suitable type of liquid metal such as Formed sodium-potassium or gallium-indium.

The arrangement of the power receiving system in the core grooves 21 means that the magnetic flux in the liquid metal 33 is practically limited to the leakage flux. So are the magnetohydrodynamic Losses that occur in the liquid metal 33 are kept to a minimum. However, it is due to the high current densities generated by the liquid metal 33 must be coped with, to a considerable heating at these current receiving points. To this heating problem To mitigate and dissipate the heat generated in this way, cooling channels 35 are formed in the current collecting ring bodies 23. By a suitable cooling fluid can be passed through these cooling channels 35,

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so that the cooling achieved is much greater than that achieved. can achieve pure air cooling. As a result, the effective cooling achieved allows an adequate evaluation of the with one Liquid metal current collection system equipped with segmented Magnet assembly.

As mentioned, the voltages generated in the conductors can be connected in series by suitable connection of the current collecting ring bodies 23 to increase the output voltage of a machine. Figure 7 illustrates schematically how this is accomplished can be. Groups with conductors 15 are shown schematically and are each provided with the reference symbol 15. In the same way the current collecting ring bodies 23 are indicated schematically. As can be seen can by connecting the current collecting ring body 23 by means of of the connections 37 in the manner shown, the voltage generated in the four groups with the conductors 15 is connected in series so that the output voltage obtained at output terminals 39 and 41 is substantially four times that in one of the conductors 15 generated voltage.

The connections 37 can be made either inside or outside the core. In other words, the connections 37 can be embedded conductors or conductors that extend from the current collecting ring bodies 23 to the outside of the ferromagnetic Core 13 extend so that the connections 37 can be made externally. The connections also do not need to be connected in series, as shown with Fig. 7, but for applications where a low voltage and high currents are required.

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are taken, the connections 37 could also be connected so that the groups are connected in parallel with the conductors.

Various possible embodiments are shown in Fig. 8-10, how they could be used for the excitation windings 17. 8 is a partial section through a superconductivity having excitation winding 17 reproduced. This winding, which does not work with superconductivity, consists of conventional ones Ladders 43 with a square or rectangular cross-section. In each of these conductors a channel 45 runs through which for cooling purposes for example, water can be passed.

According to FIG. 9, there is a superconducting winding as the excitation winding 17 Use. A Dewar vessel with Dewar walls 47 is used to insulate the winding 17. Between the dewar walls 47 there is a vacuum, in which a radiation shield 49 is also arranged in order to further reduce the heat loss.

According to FIG. 10, the superconducting excitation windings and the core as a whole enclosed by a single Dewar vessel 51, which is constructed in the same way as the Dewar of FIG.

As a result of the extremely high fields generated by superconducting windings and the resulting much higher flux densities the power collection points, the efficiency is one according to the invention constructed homopolar "machine up to a power output of

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about 100 MW larger than when using conventional conductors Fig. 8. However, this is only an assumed range and it may well be future developments in the field of magnetic shielding or other ways to reduce magnetohydrodynamic losses in liquid metals reduce, make the use of superconductors more realistic, even for lower output powers. In any case it is The structure explained here can be used in the same way for both superconducting and non-superconducting excitation windings and not limited to either option.

Patent claims :

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Claims (9)

P at ilts claims: Homopolar dynamo-electric machine characterized by a cylindrical jacket made of ferromagne ti Schein material as well as a concentric cylindrical core made of ferromagnetic Material that are rotatably mounted in relation to each other, one connected to the jacket, at intervals A plurality distributed over its circumference, combined to form a plurality of axially offset groups in relation to one another electrical conductor, a plurality of magnetic poles forming excitation coils arranged in the core, one such magnetic pole disposed adjacent to each of the group of conductors, projecting current collecting rings connected to the ends of the conductors, in which Current collecting ring body arranged in the core with liquid metal (33) cooperating with the projecting StromsainrneIringen (29). for creating an electrical connection between the current collecting rings and the current collecting ring bodies (23) containing Grooves, also through channels provided in the ring bodies for the guidance of cooling fluid. 2. Dynamoelectric machine according to claim 1, characterized in that that the jacket (11) is arranged inside the core (13) and that the conductors in the outer region of the Sheath provided sheath grooves are housed. 3. Dynamoelectric machine according to claim 2, characterized in that that a plurality of conductors are stacked one on top of the other in each jacket groove. 409837/0323 4. Dynamoelectric machine according to a dsr claims 1-3, characterized in that the core is stationary and the dumbbell is rotatable. 5. Dynamo-electric fascine according to Claim 4, characterized in that that core grooves are formed in the core to accommodate the excitation coils, and that the current collecting ring body in the core grooves are arranged. 6. Dynamoelectric machine according to claim 5, characterized in that that the shape of the core is adapted to the course of the magnetic flux in ihia. 7. Dynamoelectric machine according to claim 5 or 6, characterized in that the excitation coils as a plurality of excitation windings are formed, which are arranged in the axial direction at spatial distances from one another along the core are, and that adjacent excitation windings carry oppositely directed currents. 8. Dynamoelectric machine according to one of claims 1-7, characterized in that each group eiaer Mehr ζ aiii groups the conductor is connected to a projecting StromsammeIring (29) common to this group and that the projecting Current collecting rings corresponding Stromsaiiimelringkörper are electrically connected so that the voltages generated by the groups with the conductors in each other Series are assigned. 409837/0323 9. Dynamoelectric.-Las chine according to one of claims 1-3, characterized in that the jacket is mounted within the core and rotatable in relation to the conductors are arranged in shell grooves formed in the outer region of the shell so that the core is stationary and in correspondence with the flux distribution formed with it, the core grooves are formed in the inner part of the core, the excitation coils and the current collecting rings are disposed in the core grooves are, the conductors are connected in groups to the projecting Stromsolleiringen, each group of conductors with one of this group's common outstanding Stromsolleiring is connected and that the protruding current collecting rings corresponding Strorasamrnelringkörper are electrically connected to each other so that voltages generated in the groups of conductors are assigned to each other in series. KN / hs 5 409837/0323