GB102889A - Means for Controlling Electric Motors. - Google Patents

Abstract

102,889. Igranic Electric Co., (Cutler-Hammer Manufacturing Co.). June 28, 1916. Master control systems.-In a system of control for an electric motor by electromagnetic contactors, the line contactor and the first accelerating-contactor have shunt operating-windings with circuits completed through a hand-controller, and the other accelerating-contactors have series operating-windings. In addition to the operating- coils 9, the accelerating-contactors 4, 5 have series lock-out coils 10, and the circuit of the shunt coil 11 on the first accelerating- switch 3 can only be completed through the auxiliary contact 13 on the line contactor 2. When the hand-controller 6 is moved to its first position, the coil 12 is energized and the line contactor 2 is closed to connect all the resistance in circuit with the motor. The motor circuit includes the winding of the relay 7, and the relay contacts are opened when the motor current reaches an excessive value. When the hand-controller is moved to its second position, the circuit of the coil 11 on contactor 3 is completed, subject to the control of the relay 7. The contactor 3 cuts out the resistance section R, and the contactors 4, 5 follow automatically to cut out resistance sections R', R<2>. When the motor is suddenly reversed, the contactors open, and the relay 7 prevents the contactor 3 from closing until the current drops. In a modification, the series relay 7 is omitted, and the contactor 3 is provided with a series lock-out coil. The arrangement may be further modified to provide for additional speeds, series contactors being employed to give automatic acceleration from one speed to the next higher speed.