US794210A - Dynamo-electric machine. - Google Patents

Description

'No. 794,210. PATENTED JULY 11, 1905. 1

D. BALAOHO'WSKY &' P. GAIRB.

' DYNAM'G BLEGTRIG MACHINE APPLICATION rn-sn NOV. 21, 1902.

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zz ra/ I 110.794.210. PATENTED JULY 11, 1905.

D. BALAGHOWSKY & P. GAIRE.

DYNAMO ELECTRIC MACHINE. APPLICATION FILED Nov. 21, 1902.

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No. 794,210. PATBNTBD JULY 11, 1905.

D. 'BALAOHOWSKY 6: P. GAIRE.

DYNAMO ELECTRIC MACHINE.

APPLIOATION FILED NOV. 21, 1902.

No. 794.210. PATENTED JULY 11, 1905. D. BALAGHOWSKYK; P. GAIRE.

DYNAMO ELECTRIC MACHINE.

APPLICATION FILED NOV. 21, 1902.

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Witnaoaeo attozwiq UNITED STATES Patented July 11, 1905.

PATENT OFFICE.

DIMITRY BALACHOWSKY, OF PARIS, AND PHILIPPE (JAIRE, OF LEVALLOIS, FRANCE.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 794,210, dated July 11, 1905. I

Application filed November 21, 1902. fierial No. 132,337.

To (LZZ whont it may concern:

Be it known that we, DIMI'IRY BALAoHow- SKY, a subject of the Emperor of Russia, and a resident of Paris, and PHILIPPE CAIRE, acitizen of the Republic of France, and a resident of Levallois-Perret, France, have invented a new and useful Improvement in Dynamo-Electric Machines, which improvement is fully set forth in the following specification.

This invention relates to improvements in dynamo-electric machines whereby the demagnetizing force of the armature in these machines can be transformed into a magnetizing force, the said machines running without sparks. As a direct consequence the value of the flux due to the field-windings may be diminished to a considerable extent.

In order to render the explanations which follow as clear as possible, we have shown, by way of example, in the accompanying drawings diagrams illustrating the commutation in an ordinary continuous-current machine and diagrams illustrating the commutation as it takes place according to our said invention.

Figures 1, 2, 3, and4 are diagrams relating to the method of commutation heretofore employed. Fig. 5 is a diagram illustrating our new method of commutation. Figs. 6, 7, and 8 are developments of the coils. Fig. 9 is a diagram illustrating our method of commutation applied to a bipolar electric motor, running in both directions being provided for. Fig. 10 is a diagrammatic illustration of means for adjusting the brushes relative to each other in accordance with our invention.

To facilitate the comprehension of our invention, we will first briefly call to mind, referring to the diagrams in Figs. 1, 2, 3, and 4, the phenomena which accompany commutation and the armature reactions in a continuous-current machine.

Let us take the case of a bipolar machine of which the polarities, direction of rotation, and directions of the current are indicated in Figs. 3 and 4. In operation the currents which circulate in the two halves of the armature connected in parallel unite at e and at f, Fig. 4. It will be noticed that these points are not on the axis r 8, since one is obliged for a dynamo-machine working as a generator to displace the brushes Z Z, as indicated at 0 nthe neutral line. In fact, considering Fig. 4, it will be seen that before passing from the upper half to the lower half the section (Z will be short-circuited by the contact with two consecutive bars of the commutator and will take the position a, Fig. 3. If the brush Z was brought back behind r s, a flux of force would be embraced by the section a, Fig. 3. The latter would become the seat of an elec tromotive force, which is very low, it is true, but which would nevertheless produce a very strong current in view of the low resistance of the short circuit. Also when this short circuit is broken by reason of the passage of the section a into the other half 0 of the armature, Fig. 4, strong sparking is produced. By advancing the brushes Z Z and placing them along 0 n the section will be subjected to the action of a field which will tend to produce therein a current in the opposite direction. The two currents flowing in opposite directions will consequently neutralize each other, and the passage into the other half of the armature will take place without sparks. In an electromotor for the same reasons the lead will be to the rear of 1" s; but we retain in the succeeding parts of the specification the example of a generator, the same considerations applying in the two cases, regard being had to the secondary phenomena proper to electromotors.

According to Swinburne the magnetic action of the armature can be reduced to two components, Figs. 1 and 2. The advance of the brushes Z Z on the axis 0 n in Fig. 1 gives us two bundles of lines of force, one causing the torsion or cross-magnetization of the field and the other tending to weaken the magnetic field or to demagnetize. The arrows on the field-magnets indicate the direction of the lines of force, while those on the armature indicate the direction of the currents across the face of the armature. In Fig. 1 the conductors includedbetween the angle 2/ or between 2 and 3 at the right are connected to conductors between 1 and I on the left and tend to demagnctize, while conductorsbetween 1 and 2, connected with those between 3 and 4, tend to cross-magnetize.

In an ordinary machine account should be taken of this opposing force in calculating the number of ampere-turns required for exciting the field-magnets.

Let us suppose the brushes Z l brought back to the line 0 a, Fig. 2, it will be seen that the magnetic action of the bundle of coils included in the angle 2/ changes direction and reinforces the magnetic field in such a manner that not only is it unnecessary to add a number of ampere-turns to the excitation, but this magnetic force is utilized advantageously.

WVe have seen above the consideration viz., the excessive sparkingwhich rendered impossible this backward lead.

Many inventors have attempted to solve the problem by devising complicated windings with commutating bobbins or coils, artificial neutral points, auxiliary poles; but (lil'liculties of a practical nature have prevented these arrangements from being carried into practice on a really commercial scale. In no case has any of these systems been applied to existing machines.

By our new arrangement Fig. 5, we have brought the brushes Z I back from n n, (in the opposite direction to the movement;) but in front of this neutral line we have two other brushes Z Xv, which are connected by conductors 5 5 of suitable section and resistance to the positive and negative brushes Z, If we consider the diagram, Fig. 5, we see that in operation there are two portions of the armature 711mm, (indicated by heavy lines,) which are respectively short-circuited by the two sets of brushes +7; and Z:. For the purpose of supporting and adjusting the brushes any suitable means may be used, such as that illustrated diagrammatically in Fig. 9, in which 6 6 are brush carrying arms supported on suitable collars and adapted to be manually adjusted relatively to each other. Such means being well known in the art no further description is deemed necessary. Let us now imagine the phenomena which result, and for that purpose take the portion at of the armature. This portion of the armature comprises coils which are the seat of currents flowing in the reverse direction. In fact, in front of the neutral line 0 w. the current in the coils has a direction opposite to the current in the coils behind 0 11/. It follows therefrom that in the closed circuit, if the brush Z; is sufficiently advanced, the electromotive force of the coils in front of the neutral line is greater than that of the coils behind. The resultant electromotive force in the portion m will be equal to the difference between these two forces. rection of this current is that of the coils in front of the neutral line. The magnetic action of this current thus adds itself to the field produced by the field-magnets and we have the conditions in Fig. 2.

If weintercalate an y equal resistances, fixed or variable, useful or not, between +1 and ,l: and Z and Z/ we can vary the course of the currentin the zone of commutation. This variation will involve a modification of the current in the machine, which may be of some use in certain cases. However, it is of importance that the current passing in the zone of commutation should not be less than the current passing in the armature-conductor. It will be seen why later on, in studying the different phases of the commutation. It is evident that to all the positions in rear of the +1 and t brushes there correspond positions in front of the brushes 1 and A In order to increase the zone of commutation,one should then act on the brushes in front and in rear, the +1 and -Z brushes being fixed, as are Z: and 1:, on a common collar. It will be easily deduced that with an arrangement of such elasticity one can very simply neutralize the demagnetizing force, render it progressively magnetizing---that is to say, ren- (101' the machine compoundorover-compound or even obtain a machine operating without windings on the field-magnet.

Let us now turn to Figs. 6, 7, and 8. which show us the different phases of the passage of a section of a part of the armature into the zone of commutation and from there into the other part of the armature. Fig. 6 shows us the section t with the commutator-bar under the brush +1 and the section w connected to the bar under the brush I at the moment at which the current is taken off. In the positions shown in Figs. 7 and 8 the sections land 11- are themselves short-circuited. For the section 6 the short-circuit is only apparent. One can easily note this by following the ar rows indicating the directions of the CLlllGI'll]. Since the section 6 takes the position I, the current which circulates there is destroyed by the current from the zone of commutation, and the two conductors v 4.1, connected by the brush become the seat of parallel current in the same direction. A current cannot thus be set up in the section. Also when the conductor Q12 leaves the brush there will be no rupture of a current, and consequently no sparks. In the section 7/ the conductors n and 4; become the seat of currents in the same direction which connect the circuit of the zone of commutation, in fact, of the brush Z: to the sections of the armature, two parallel paths ofler themselves to the passage of the current and, when the conductor 2; leaves the brush Z: there is no rupture and naturally no sparking. If the width of the brushes exceeds that of a hloreover, the disegment of the commutator, it would only increase the number of conductors in parallel, (of the type 41;) but by reason of the differ ences of resistance of these paths the intensity of the current would be slightly different in each conductor, (of the type 4;.) Nevertheless a wid th of eight-tenths of segment of the commutator gives good results.

From what is stated above one deduces immediately the possibility of obtaining a fixed lead for all loads and for a common direction of rotationthat is to say, the lead of the brushes can be so regulated that the displacement of the neutral line in advance or behind the geometrical axis in consequence of reversal of rotation causes this line to form an angle A, for example, with the right-hand brush and an angle B with the left-hand brush, or the displacement forms an angleA with the left brush and an angle B with the right brush.

In our diagrams the zones of commutation are exaggerated to facilitate the comprehension of the invention. In practice a small number of sections only are under these conditions. v

In an electromotor it is necessary to imagine the case of running in both directions. For this purpose the brushes and 7c and 7s, Fig. 9, are arranged symmetrically relatively to the two neutral lines in front and behind. Thus there is produced a compound machine with constant lead for all loads, whatever he the direction of rotation, an advantage which is very valuable in an electromotor used for traction purposes.

We insist particularly on the point that the principle above described is applicable to the armatures of existing machines with the coils in series or in parallel with ring or drum armatures and bipolar or multipolar. VVorking according to this principle the armatures of continuous-current machines have thus no limit to their load but the heating.

One has the advantage with our improved system of employing air-gaps, offering the least possible reluctance and of putting in the greatest possible number of coilsthat is to say, so many as are permitted by the internal resistance and the heating. If it is wished that the rise of temperature shall not be great, it is necessary to increase the diameter of the armature; but here one is limited by the peripheral speed.

Without increasing the peripheral speed, while insuring a coolingsurface, it is possible to put in double the number of coils, which gives to the flux a value reduced by half. The presence of twice the number of air-gaps is not an obstacle, it being granted that we have all the advantage of reducing the reluctances of these air gaps, the limit of the sparkless point not existing for this kind of machines.

We shall use the term zone of commutation in the claims as indicating a certain angular distanceincluded between the pairs of brushes and audit in, this being in a motor determined by the peripheral intersections of radii subtending the angle 2/ being the generator the angle would he usually 2/ as determined by the desire to obtain a resultant electromotive force in the short circuited coils. All this has been explained; but it should be noted that our zone of commutation includes coils both in advance and to the rear of the median axis of the armature, (marked 1 s in Figs. 4 and 5.) We believe we are absolutely thefirst to discover the possibility of such an arrangement, and we shall therefore claim our invention broadly, and our claims are to be so construed.

Having now particularly described and ascertained the nature of our invention and in what manner the same is to be performed, we declare that what we claim is 1. In a dynamo-electric machine,a field having opposing poles, an armature intermediate said poles, a commutator, a double set of brushes connected two and two each of said two connected brushes embracing a zone of commutation having the neutral point or points within said zone, whereby demagnetizing force of the armature may be transformed into a magnetizing force to assist the field and. without sparking at the brushes.

2. In a dynamo-electric machine, a field, a commutator, a double set of brushes in operative relation thereto and connected two and two, means for regulating the currentthrough said connection, each two connected brushes embracing a zone of commutation having the neutral point or points within said zone whereby the demagnetizing force of the armature may be transformed into a magnetizing force to assist the field and without sparking at the brushes.

3. In a dynamo-electric machine, magnetic poles, windings, a commutator, and brushes cooperating with said commutator to produce a zone of commutation including a plurality of coils both in advance and in rear of the median axis of the armature and having the neutral line or lines lying within said zone.

4:. In a dynamo-electric machine, opposite field-poles, armature-windings exposed thereto, a commutator for said windings and means cooperating with said commutator to produce a zone of commutation including a plurality of coils both in advance and in rear of the median line of the armature and having the neutral line or lines lying within said zone.

5. In a dynamo-electric machine, means for neutralizing the demagnetizing force or of transformingprogressively thedemagnetizing force of the armature into a magnetizing force and permitting the machine to run without sparking, comprising field-magnets,arn1aturewindings exposed thereto, a commutator, a

angle of lead of the brushes and In a double set of adjustable brushes connected two and two cooperating therewith to produce a zone of commutation including a plurality of coils and having the neutral line or lines lying Within said zone, thereby attaining a fixed lead for all loads.

In testimony whereof we have signed this specification in the presence of two subscribing; witnesses.

'DIMITRY EAL AC HO WS K Y PHILIPPE GAIRF. Witnesses FRANCIS Cm monn, AL'nXANonE SAUL.

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