US293432A - Electrical generator amd svjotor - Google Patents

Description

(No Model.)

T. A. EDISON.

ELECTRICAL GENERATOR 0R MOTOR. No. 293,482. Y Patented Feb. 12, 1884.

ATI'EST:

UNETED States THOMAS A. EDISON, OF MENLO PARK,

ELECTRlCAL GENERATOR AND i- "CT@ itnw JERSEY.

SPECIFICATION forming part of Letters Patent No. 293,432, dated. February 12, 1258 2. Application filed October 18, 1853 (X0 model.)

To LZZ whom, it may concern.-

Be it known that I, THOMAS A. EDISOX, of Menlo Park, in the county of Middlescx and State of New Jersey, have ii'lventedanew and useful Improvement in Electrical Generators and Motors, (Case. No. 602,) of which the following is a specification.

This invention relates to the construction of dynamo-electricmachinesand electro-dynamie motors having continuously-wound bobbins connected at intervals to commutator-bars, whereby the sparking at the commutator will be greatly reduced or wholly obviated, overcoming the necessity for changing the current-cob lectors upon the connnutatorin accordance with variations in the load upon the machines when used either as generators or motors, increasing the capacity of the machine and decreasing the heat generated in the armature-coils, and also diminishing the wear of the commutators and the collectors. This I accomplish by opposing the electro-motive force of the coils as they are shortcircuited at the commutator (by the bridging of commutator-bars by the current collectors) by acounter electromotive force. This counter electro-inotiveforceis preferably equal or nearly equal to the electro-motive force of the short-cireuited coils, in which case no current will flow in the short-circuited coils and the sparking will be completely obviated; or the counter force may be somewhat less or even greater than the direct force, but not sufficiently one way or the otherto make the spark due to the current produced by the predominating electro-motive force of practiealimportance. The counter force is produced by making the connections between the bobbin and the commutatorbars through conductors which pass through the field of force, and in which there is a counter electro-motive force opposed to the direct force of the short-circuited coils. These connections are preferably in the form of loops upon the armature.

In machines with continuous windings, the commutator-bars have been heretofore connected with the armature bobbin by conductors running directly from the commutator-bars to the bobbin. By this invention, however, each connection is made by a conductor which is connected to the bobbin, and is carriedbael; on the armature-loop from the point of con nection therewith, and follows it one or more times around the armature, and is then con nected to a commutator-bar. (ihe extra loops may be conductors of the same size as the bobbin 5 but much smaller conductors are preferably used, and since each extra loop is in circuit a portion of the time cnly,the heat due to the main current is dissipated. A counter force equal to the direct force is obtained by giving each extra loop the same length as one loop or section of loops of the main bobbin; or in constructions where this is not desirable the extra loops may be placed in advance of the loops of the main bobbin, so thatas each main loop or section of loops is short-cireuited the opposing extra loop or section ot'loops is in a stronger magnetic field, and in this way the counter force of the extra loop can be made equal or nearly equal to the direct force of the short-circuited loop. I

This invention is applicable to all continuously wound machines, whether of the Gramme, Siemens, or other type.

In the accompanying drawings, forming a part hereof, Figure 1 is perspective view of a number of armatureloopsremoved from the armature and of a numberof commutatorbars, the connections between the loops and bars beingshown by dotted lines; Fig. 2, a perspective view of a wound armature of the Siemenstype and a commutator with two commutatorconneetions illustrated; and Fig. 3, a side elevation of a wound armature ot' theGrannne typewith the commutator in vertical section, all the commutatorconnections being illustrated.

A represents commutator-bars, and B the coils or loops of a eontinuously-wound armature. Theiield-magnet, thelocation of which will be well understood, is not shown in any of the figures.

(1 represents the conductors connecting the loops with the commutator-bars. These conductors are wound asloops upon the armature, and hence pass through the held of force, and in them is developed a counter electromotive force which neutralizes wholly or partially the electro-inotive force oi" the coils as they are short-circuited. It ill be seen that each con ductor 0, instead of extending from the point of connection with 13 directly to a connnutater, is runbacl; upon the coil 13, to which it is connected, and follows that coil around the arm-a .sponding main loops; and hence I inake no ture, and is then connected to a commutatorbar. If the winding B is a plural winding, each conductor C may also be wound two or more times around the armature. In Fig. 2 two connections only are shown for clearness; but it will be understood that the other commutator-bars will be connected in the same way with the armature-coils. In Fig. 3 the connections 0 pass once around the ring-armature beforebein g connected with the commutator-bars; but these connections may be run two or more times around thearmature,to give the required counter electro-inotive force.

The operation is not dependent upon the resistance of the extra loops, but upon their length and position with reference to the correclaiin herein to the interposition of an extra resistance between the commutator and the armaturecoils. A construction dependent upon the resistance is described in my application Serial No. 114,282, and that invention is therein claimed. Neither do Iclaim herein a resistance external to thecurrent-collectors forming a bridge of high resistance between the shortcircui-ted commutator-bars, for this is claimed in my application Serial No. 114,281.

What I claim is 1. The method of overcoming wholly or pan '1 tially the spark at the commutators of dynamo or magneto electric machines or electro-dynamic motors, consisting in developinga counter electro-motive force opposed to the electromotive force of the armature-coils as they are short-circuited, substantially as set forth.

2. In an electrical generator or motor, the combination, with the armature and commutator, of means for throwing a counter e1eotromotive force into the armature-coils as they are short-circuited, substantially as set forth.

3. In an electrical generator or motor, the combination, with the armature and commutator, of conductors connecting the armaturecoils and commutator-bars and passing through the field of force, substantially as set forth.

4. In an electrical generator or motor, the combination, with the armaturecoils and the commutator-bars, of extra loops wound upon the armature, and connecting the armature coils and com mutator-bars, substantially as set forth.

This specification signed and witnessed this 17th day of October, 1883.

THOS. A. EDISON.

Witnesses:

WM. H. Mnanowonorr, EDWARD H. PYATT.

Images