GB191510752A - Improvements in Electric Motor Starters & Controllers. - Google Patents

Abstract

10,752. Schattner, E., Travis, T. G., and Walton, J. R. July 24. [Cognate Application, 661/15.] Systems for continuous-current motors only; controllers, actuating-mechanism for.-Means are provided in motor-starters to prevent the re-establishment of the motor circuits after switching off, until the speed of the motor has dropped to a particular value. The starter shown in Fig. 1 has a detent g which can be moved to the position shown in dotted lines by the solenoid l connected across the motor armature only in the initial position of the starter arm. When the motor is started from rest, the arm is moved on to the contacts b to connect a diverter resistance across the motor armature and to connect the usual starting-resistance in series with the armature. Further movement of the arm breaks the diverter circuit and cuts out the starting-resistance. If the no-volt coil e releases the arm when the motor is running, the arm is returned by the spring f and the coil l is energized, so that the detent g locks the arm in its zero position. It is only released when the back electromotive force of the motor diminishes sufficiently for the solenoid to release the detent. In the modification shown in Fig. 3, the back-electromotive-force relay p controls a normally closed contact in the actuating circuit of the line contactor.