PROTECTION FOR TRACTION MOTORS Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: invention refers to protection of traction motors of city electric transport against overloads related to voltage surges appearing at moment of break of supply electric circuit, for instance, during passing by mobile unit of crossings, during loss of contact of current collector with contact system, etc. Gear for protection of traction motors has diode connected in parallel to excitation winding of traction motor is supplemented with diode bridge which one diagonal includes resistive-capacitive filter and which other diagonal has blocking capacitor. Diode bridge and blocking capacitor are connected in parallel to excitation winding of traction motor. EFFECT: increased reliability of protection of traction motor against overvoltages related to short-time loss of voltage, simplified design of gear. 5 dwg