US697016A - Starting device for electric motors. - Google Patents

Description

No. 697,0I6. Patented Apr. 8, I902. a. H. READ.

STARTING DEVICE FOR ELECTRIC MOTORS.

(Application flhd Nov 29, 1901.; (No Model.)

witnesses: Inventor:

W, Rober' H.F?ead,

WMZQQ m: Nuflms PETERS co, Pworouma. wAsumaToN. n. c.

UNITED STATES ROBERT ll. READ, OF SOHENEOTADY,

ELECTRIC COMPANY, A COR STARTING DEVICE FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 697,016, dated April 8, 1902. Application filed November 29, 1901. ficria No 83,966. (No model.)

T to zuhmn/ it rlttty concern.-

Be it known that 1, ROBERT ll. READ, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Starting Devices for Electric Motors, (Case No. 2,398,) of which the following is a specification.

In starting up electric motors, particularly IO such as are not provided with rheostatic switches for graduallyturnin g on the current, much annoyance is experienced by the opening of the automatic circuit-breaker commonly provided to protect the motor against r5 overload, the blowing of the circuit-breaker being occasioned by the large starting-current taken by the motor. The trip-coil, being calibrated to protect the motor against running overloads, is easily operated by the very heavy overload which the motor takes during the momentary interval from rest to partial speed. Devices have been proposed to correct this by changing the calibration of the circuit-breaker during the operation of closing the starting-switch. My invention accomplishes the same object in a simpler way by providing during the closure of the startin -switch a by-pass around the automatic circuit-breaker by which part or all or the current is carried by the bypass, and

therefore shunted away from the circuitbrealier, thus avoiding its blowing, and, further, by adapting the switch by a further range'of movement to cut out the by-pass,

3 5 leaving the branch containing the automatic circuit-breaker the sole path for current to the motor, thereby permitting it to accurately respond to line conditions and trip on the attainment of the definite degree of overload 40 for which it was calibrated.

The switch may be of any simple construction which accomplishes these progressive functions, the one shown involving two sets of clips cooperating with the switch-blade in such. a way that one clip may be shifted out .of contact with the blade when it is fully closed.

My invention therefore comprises a motorstarting organization consisting of an automatic circuit-breaker and a starting-switch for completing a bypass around the circuit- PATENT OEEIcE;

NEXV YORK, ASSIGNOR TO GENERAL PORATION OF NEXV YORK.

breaker and then opening it while starting the motor.

In the accompanying drawing is diagrammatically shown apparatus for carrying out my improvements.

1 represents an electric motor of any desired type, which maybe supplied from a source of any character, direct or alternating, diagrammatically shown as a pair of mains 2 8.

l represents an automatic circuit-breaker, the switch and trip-coil 5 of which are in se rice with the motor.

6 is a by-pass around the circuit-breaker, or at least around the trip-coil of the circuitbreaker, by which a part or all of the energy flowing through the motor may be carried. This may, if desired, be protected by a fuse or other suitable device. It is preferably so graduated in resistance as to absorb a definite part of the current supplied to the motor, varying with the type of motor and being sutficiently low in reference to the path containing the trip-coil of the circuit-breaker as to prevent a current large enough to trip the cir- 7 5 Quit-breaker when the motor is being started from a state of rest. For example, it mig t be adjusted to carry an equal current with the trip-coil branch when in parallel relation to the latter in a case where the motor might 8o draw a starting-current of seventy-five per cent. excess over its maximum running load.

Z represents the starting-switch, which may be of any suitable type, adjusted to throw in the auxiliary branch when the circuit is closed and then cut it out. A simple and effective arrangement for attaining this end is shown and consists of two pairs of clips for the switch-blade, one of which leads to the path 6 and the other to the path 5. These are 0 shown at S 9, the former being bent so as to bring its two jaws in proximity at the top, thus forming a contact while the switch is in the dotted position, thus putting current in the path 6, and in being lowered connecting 5 the two paths by engaging simultaneously clips 8 and 9 and in the final stage of its movement resting in contact with the clip 0, as will be sufficiently evident from the drawing;

It will be seen, therefore, that the first great too rush of current is taken by the path 6, which may, if desired, be protected by a fuse or evident that the circuit-breaker is not actuated if the motor is started under ordinary conditions, and it will be unnecessary to hold it closed or tie it closed, as is sometimes done to the danger of other apparatus. What I claim as new, and desire to secure I by Letters Patent of the United States, is

1. A starting device for electric motors or other translating devices absorbing heavy starting-currents, comprising an automatic magnetic circuit-breaker designed to out the motor out of circuit on running overloads,

and a switch for closing the motor-circuit through an auxiliary path when first starting the motor.

2. A starting device for an electric motor 01' other translating devices absorbing heavy starting-currents, comprising an automatic magnetic circuit-breaker, a parallel branch around the trip-coil of the circuit-breaker, and a starting-switch adapted to first connect the branch around the trip-coil in circuit with the motor,and fina-llyleave the circuit-breaker only in circuit.

3. A startingdevice for electric motors or other translating devices absorbing heavy starting-currents, comprisingan automatic magnetic circuit-breaker, a protective shunt therefor, and a switch for diverting the current first through the shunt and then through the circuit-breaker.

4:- A starting device for electric motors or other translating devices absorbing heavy starting-currents, comprising an automatic magnetic circuit-breaker, a shunt around the trip-coil, and a starting-switch provided with contacts for coupling the two paths in parallel and then cutting .out the by-pass around the trip-coil.

In Witness whereof I have hereunto set my hand this 22d day of November, 1901.

ROBERT H. READ, W'itnesses:

BENJAMIN B. HULL, ll/IARGARET E. WooLLEY.

Images