FIELD: electrical equipment of diesel locomotives with electric transmission. SUBSTANCE: device has series-connected resistors connected to armature windings of traction motors according to measuring bridge circuit, diode bridge rectifier, capacitor with discharge resistor, relay, semiconductor switch and isolation diodes. Novelty is provision of isolation diodes and semiconductor switch built around dynistor or transistor and voltage stabilizing diode circuit. When voltage across capacitor rises to relay setting value, switch closes relay winding circuit and relay cuts in. Thus device implements response equal to response of relay. EFFECT: enhanced reliability of operation. 4 cl, 3 dwg
