GB122085A - Improvements in Electric Motor Controllers. - Google Patents

Abstract

122,085. Igranic Electric Co., (Cutler- Hammer Manufacturing Co.). March 20, 1918. Controllers, polyphase.-In a polyphase motor controller which connects the motor to the supply through compensator windings for starting and through overload protective means for running the motor windings are permanently connected to the compensator windings at their tapping-points. The drum controller C has contact segments arranged in three sets corresponding to the three leads L<1>, L<2>, L<3> of the supply, and a hold-on coil 25 causes a latch 23 to hold the controller when it is in the running position. When the segments are moved to the left from the position shown in Fig. 1, the compensating-windings 1, 2 are connected across the phases L<1> L<2>, L<3> L<1>, and the motor is supplied from the lead L<1> and intermediate taps on the windings 1, 2. When the segments are moved to the right for running, the compensator-windings are disconnected and the motor is supplied directly from the mains. The windings of the overload relays 3, 4 are included in the circuits of the leads L<3>, L<2> and an excess current causes them to operate so that the winding 25 releases the latch 23 and a spring returns the controller to zero. In a modification, the change of connexions for a three-phase motor is obtained by using a three-pole double-throw knife switch. In another modification, Fig. 3, for a two-phase motor, the controller drum has four sets of segments corresponding to the four leads L<1>, L<2>, L<3>, L<4>, and the motor is supplied through the compensating-windings 56, 57 for starting and through the fuses 58, 59, 60, 61 for running.