FIELD: electrical engineering; protection of motors in industry and agriculture. SUBSTANCE: emergency protective gear is provided with newly introduced transient temperature compensating unit in the form of differential amplifier. Joint use of mentioned unit and overtemperature, voltage-unbalance, and phase-failure protective units incorporated in prototype enables reliable operation of protective gear in emergency situations during both single-phase and multiphase ground faults as well as during motor starting at supply voltage unbalance when unbalance level is too low for voltage unbalance and phase-failure protective units to respond to. EFFECT: enhanced reliability and enlarged functional capabilities of protective gear. 1 dwg
