DEVICE FOR MEASUREMENT OF LEAKAGE CURRENTS IN TROLLEYBUS AND FOR PROTECTIVE DISCONNECTION OF TROLLEYBUS FROM SUPPLY NETWORK WHEN LEAKAGE CURRENT EXCEEDS SPECIFIED VALUE Russian patent published in 1994 - IPC

FIELD: electrical engineering. SUBSTANCE: device relates to means for protection of man against leakage current to frame of rolling stock supplied with direct current from two-wire contact system. Device has measurement unit with leakage current indicator, unit for provision of no-current pauses incorporating contactless pickup of load current, circuit of program control, contactless commutated switches, circuit of disconnection monitoring connected in series. Measurement unit includes distributor, current keys, source of operational supply. Leakage current indicator has standard resistor, line of comparators, source of reference voltages, memory circuit and histogram display. Measurement unit is connected through current keys to power circuits of trolleybus and through standard resistor - to its body. In addition device incorporates unit of monitoring of state of doors of trolleybus (open/closed) connected to circuit of program control and to standard desk of control over doors. EFFECT: simplified design, improved reliability and safety. 2 cl, 1 dwg