DEVICE TO CONTROL RESISTANCE OF STARTING OR BRAKE RESISTOR OF ELECTRIC ROLLING STOCK TRACTION MOTORS Russian patent published in 1997 - IPC

FIELD: electrified transport; DC rail vehicles, underground cars, electric trains, street cars, trolley buses. SUBSTANCE: device has thyristor switch of N steps of starting resistor, more setting unit, notching up and down switches, control pulse source, inhibit unit, flip-flop unit and optoelectronic relay unit with N flip-flops and N optoelectronic relays equal to number of controlled resistor steps. In process of operation functioning of device is checked. If any control circuit of step switch fails to operate, following step is not engaged. This prevents current surges in traction electric motor and protects motor from ring fire on commutator. EFFECT: improved stability of operation of traction motor at short-time separation of current collector from contact system. 1 dwg