US1019491A - Induction-motor. - Google Patents

Description

K. KUHLMANN & H. MULLER.

INDUCTION MOTOR.

APPLIOATION FILED 11.53.27, 1906.

Patented Mar. 5, 1912.

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UNITED STATES PATENT oEEIoE.

KAEL KUI'ILMANN, OE BERLIN-PANKOW, AND rIEINEICH MLLER, or BERLIN, GEE- MANY, AssIeNons To GENERAL ELECTRIC COMPANY, A CORPORATION OE NEW YORK.

lINDUCTION-MOTOR.

Specification of Letters Patent.

Application led March 27, 1906. Serial No. 308,269.,

To all whom Zt'may concern:

` Be it known that we, KARL KUHLMANN, a

subject of the Emperor of Germany, residing at Berlin-Pankow, Germany, and HEIN- RICH MLLER, a subject of the Emperor of Germany, residing at Berlin, Germany, have invented certain new and useful Improvements in Induction-Motors, of which the following is a specification.

Our invention relates to induction motors, and more especially to single-phase motors; and its object is to provide an improved form of starting device.

In order to prevent a heavy flow of current at starting, it is desirable to have ahigh resistance in the secondary circuit of an induction motor, which should be cut out when the motor is up to speed. For this purpose automatic centrifugally-actuated devices have been employed heretofore either to short-Circuit a resistance in series with the secondary winding or to close the circuit of an auxiliary secondary winding. In order to make single-phase induction`motors 'selfstarting, it is necessary to arrange them with special connections at starting, either with a special starting winding or with by reference to the accompanying drawings;

ning and vhaving phase-splitting devices, or both. The Ystarting connections are broken and running connections established when the motor 1s up to speed. This has been accomplished heretofore both manually and automatically.

Our invention, in one aspect, consists in thecombination with an alternating current motor having different 'connections of the primary member for starting and for runtwo secondary windings, one a starting winding and the other ay running winding, automatic means serving to change the primary connections and also to short-circuit the secondary running winding. V

Our invention also 'com rises a number of other features whichwillst be understood in Which- Figure 1 shows diagrammatically the ciri cuit connections of a single-phase Induction motor arran ed in accordance with our invention; an Figs. 2 and 3 show the construction o the automatic ,starting device.

Inthe drawings, A represents the main rimary winding of the motor, adapted to ge connected through the main switch S to i and insulated from a bearing o a source of alternating-current indicated by the conductors a. B represents the auxiliary startingv winding connected in parallel with the main windin and having in series with it the phase-s ifting device b.

y C represents stationary collectorl rings connected in series with the auxiliary vwinding B. 1

c represents a Contact carried by the rotor and arranged at starting to bridge the collector rings G, so as to close the circuit of the starting winding B.

The rotor or seconda member is shown provided with two win ings,-One a squirrel-cage starting winding D of high resistance; the other an open-circuited coil running winding E of low resistance.

F represents a switch carried by the rotor and adapted to engage the contacts f f connected to the low-resistance winding E, so as to short-circuit this windingwhen the motor is up to speed.

The mechanical construction of the automatic device controlling both the Contact c and the switch F is shown in Figs. 2 and 3. The contact c" is carriedby a pivoted lever H, w 'ch is normally held by' a spring h in the p sition shown in Fig. 2, so as to press the contact c into engagement with the collector rings C, which may be supported upon `the motor, as indicated in dotted lines 1n Fig. .3. The switch member F consists of a sleeve loosely mountedon the shaft and provided with projecting contact members adapted, when moved to the position shown in dotted lines, to engage the stationary 'contacts f, which are connected to points on the low-resistance winding, as shown in Fig. l. The member F is engaged b`\a pin on the centrifugally-actuated mem er G. At starting this member is held by a spring g in the position shown in full lines, thereby holding the switch member F outiof engagement with the'contacts f. When the ,motor reaches a predetermined speed, the member 'G is thrown Outward by centrifugal force, asindifcated by the arrow into the position :Patented Mar. 5, 19.12.

shown in dotted lines, thereby shifting f switch member F into the dotted-line Aposition so as to short-circuit the low-resistance thereby raising contact c from collector rings C and opening the circuit of the starting winding B. ln this manner a single device serves both to make the necessary changes in the primary circuit from starting to running connections, and at the same time to decrease the e'ective resistance in the secondary when ythe motor is up to speed. Since the centrifugal devicerdoes not engage the lever H until it begins to move outward, the contact c is held by its spring firmly on the collector rings until it is lifted quickly at the proper moment.

We do not desire to limit ourselves to the particular construction and arrangement of parts here shown, but aim in the appended claims to cover all modifications wh1ch are within the scope of oui1 invention. i

What we claim as new and desire to secure by Letters Patent oit' the United States,

i. ln combination with an alternating current motor having di'erent connections of rent' motor having different connections of 'the primary member for starting and for V'running and having twosecondary windings, one -a squirrel-cage starting winding of high resistance and the other a running I Winding of low resistance, automatic means serving to change the primary connections and also to short-circuit the secondary running Winding.

3. ln a slngle phase motor, a primary member having a main windingand a start-- ing winding, a secondary member having a starting winding and a running winding, and automatic means serving to cut the primary start-ing winding out of circuit and also to short-circuit the secondary7 running winding.

4.-. ln a single phase motor, a primary member having a main winding and a 'starting Winding, a secondary member having a squirrel-cage starting winding.A of high re- `sistance and a running winding of low resista-nce, and automatic means serving to cut the primarystarting Winding out of circuit and also to short-circuit the secondary running winding. i

5. ln combination with an alternatingi current motor havlng dierent connectionsl of the primary member for starting and for Loiaeei running and having two secondary wind-' ings, one sliort-circuited and of high resistance and the other open-circuited and oi2 low resistance, automatic means arranged both to change the primary connections and to closethe circuit of the low-resistance Secondary winding when the motor is up t0 speed.

. 6. in combination with an alternating current motor having different connections of the primary member for starting and for running and having two secondary windings, one short-circuited and of high resistance and the other open-circuited and of 10W resistance, centrifugally-actuated means arranged both to change the primary connections and to close tlic circuit of the lowresistance secondary winding when the motor is up to speed.

7. In an induction motor, a main primary winding, a starting winding, a high-resistance short-circui/ted secondary winding, a low resistance open circuited secondary winding, and a centrifugally-actuated device arranged to open the circuit oitl the start` ing Winding and to close the circuit of the. low-resistance secondarywinding when the motor is up to speed. i l

8. In yan induction motor, a stator and a rotor, a starting winding, stationary collector rings in circuit with said winding, a contact carried by the rotor adapted to bridge said rings, other contacts carried by the rotor 'adapted to vary the effective resistance of vrotor ladapted `to bridge said rings, and a centrifugal device carried by the rotor and controlling said contact but separate therefrom.

l0. lin an induction motor, a starting winding, stationary collector rings in circuit with said winding, a contact movably carried by the rotor and adapted to bridge saidI rings, means for holding said contact in engagement with said rings at starting, and

a centrifugal device arranged to be out of engagement with said contact at starting,

but when moved by centrifugal force to engage and shift said-contact.

ln witness whereof, We have hereunto set our hands this 12th day of March, 1906.

KARL KUHLMANN.

y y HELNRLCH MLLER.

- llitnesses: i. JULIUs RUMLAND, KARL Roemenen.

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