US831446A

US831446A - Alternating-current motor.

Info

Publication number: US831446A
Application number: US24208605A
Authority: US
Inventors: Marius C A Latour
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1905-01-21
Filing date: 1905-01-21
Publication date: 1906-09-18
Anticipated expiration: 1923-09-18

Description

PATENTED SEPT. 18, 1906.

M. 0. A.YLATOUR. ALIERNATING CURRENT MOTOR.

APPLICATION FILED JAN. 21, 1905.

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mcTrius CALaC'oun h y UNITED STATES OFFICE- \lAltlUS O. A. LATOUR, OF PARIS, FRANCE. ASSIGNOR TO GENERAL ELECTRIC COMPANY. A CORPORATION OF NEXV YORK.

ALTERNATING-CURRENT MOTOR.

Application filed January 21,

To all whom, it mag/concern:

Be it known that I, MARiUs C. A. Laroun,

1 a citizen of France, residing at Paris, France, l

' Figure 1 shows an alternating-current mobrush-lifting device, and

have invented certain new and useful Improvements in Alternating-Current Motors, 1 of which the following is a specification.

' My inventionrelates to alternating-current l motors of the commutator type; and its object is to improve the operation and efiiciency of such machines. i As is well understood in the art, the armature-currents are generally a maximum at starting, and the currents induced in the ar 1 mature-coils short-circuited by the brushes i are much greater at starting than when the i motoris up to speed,bothbecause the motorcurrents and the resultant fields are stronger at starting and also because there is present i no electromotive force due to rotation which may serve, to reduce the amount of short-circuited current. In order to prevent undue heating of the brushes and commutator at. starting, it is necessary to provide a large brush contact-surface to carry the heavy i short-circuited currents. When the motor is up to speed, this large brush co'ntactsurface is not required and produces unnecessary losses dueto the excessive brush-friction. l my invention I provide a novel arrangement of brushes, whereby sufficient brush contact-' surface isafforded at the start for satisfacto rily handling the .starting currents with 1 means for reducing thebrush contact-surface as the motor speeds up, thereby eliminating losses due to unnecessary brush-friction. My invention consists in providing auto- 1 matic means for lifting a portion of the brushes out of engagement with the commutator without changing the circuit connections of the motor as the motor speeds up. 1 My invention will best be understood by i reference to the accompanying drawings, in i whichtor with brushes arranged in accordance with my invention. Fig. 2 shows a detail of the Fig. 3 shows a del 4 l tailof the controlling means for the brushlifting device.

' In Fig. 1, A re resents the armature, and

The field is provided with field-coils f, which may be of the distributed or concentrated 1 type. The arrnature' is provided with the l Specification of Letters Patent.

- merely reduces the number of.brushes in each set, thereby diminishing brush-friction and losses without changing the circuit connecti one of the machine.

One sui table construction of the electromagnets is shown in Fig. .2, in which the core (1 of the magnet D carries a spindle d, at the lower end of wh ch is secured the brush B,

vertically movable in the inclosing box or casing F. :The spindle d carries a collar or washer (1, against whichbears a compres sion-spring G. This spring tends to lift the core (1 and brush B", while the coil D when en ergized tends to ull the core (1 downward,

forcing the brush against the commutatorsurface. Thus ifmeans are provided for energizing the coil D at the start the brush B may be held in engagement with the commutator, and if the coil D is denergized as the motor speeds up the spring B willlift the brush B away from the commutatoi', thereby preventing unnecessary brush-friction.

One arrangement for controlling coil D is shown in Figs. 1 and 3. H representsan arm 1pivoted at h t e spring I when the motor is at rest. The arm H carries a bridging memberJ, which is adapted when the arm H .is moved outwardly by centrifugal force to engage the contact j, carried by the collector-rings K.

Thus as the speed of the motor passes a redetermined limit the collector-rings K wi be electrically connected by contact J. This action may thereby allowing the springs to lift the brushes B out of engagement with the commutator.

Obviously, other arrangements for lifting brushes B at predetermined speed may bewithin the scope of my invention.

and held against thestop h be utilized to short-circuit the magnet-coils D, as is indicated in Fig. 1,

What I claim as new, and desire to secure by Letters Patent of the UnitedStates, is

1. In an alternating-current, machine of the commutator type, means for automatically lifting a portion of the brushes out of engagement with the commutator without changing the circuit connections of the ma chine when the speed of the machine rises above a predetermined limit.

.2. In an alternating-current machine of the commutator type, electrically-controlled means for automatically lifting a ortion of, the'brushes out of engagement wit the commutator Without changing the circuit connections of the machine when the speed. of the machine rises above a predetermined limit.

3. In an alternating-current machine of the commutator type, electrically-controlled means for automatically lifting a portion of the brushes out of engagement with the com- I mutator without changing the circuit connections of the machine, and a centrifugal device controlling said lifting means.

4. In an alternating-current machine of the commutator type, electromagnets operatively connected to aportion of the commutator-brushes and adapted when energized to hold said brushes in engagement with the commutator, and sprin s opposing the action of said magnets and ten ing to lift said brushes from the commutator, the electri'callycontrolled brushes being arranged in axially alined sets with the other brushes so that the lifting of the electrically-controlled brushes.

from the commutator does not change the circuit connections of the machine 5. In an'alternating currentmachine of the commutator type, electromagnet's opera tively connected to a portion of the commutator-brushes and adapted when energized to hold said brushes in engagement with the Lranged in axiallv-alined sets with the other brushes so that the lifting of the electricallycontrolled brushes, from the commutator does not change the circuit connections of the machine.

6. In an alternating-current machine, a distributed armature-Winding provided With a many-part commutator, a plurality of sets of aXially-alined brushes bearing on said com-" mutator, and means for automatically lifting a portion of the brushes of each set out of engagement with the commutator when the speed of the machine rises above a predetermined limit.

In witness whereof I have hereunto set hand this 17th day of January, 905. v

MARIUS C. A.- LATOUR.

Witnesses HELEN Onronn, E. C. HOLLISTER.