OVERCURRENT PROTECTIVE GEAR FOR AC INSTALLATIONS Russian patent published in 1999 - IPC

FIELD: power engineering; overcurrent releases of circuit breakers. SUBSTANCE: protective gear has current transformers, rectifier, measuring device, and final element. Measuring device has voltage regulator, two comparators, resistive divider, time-setting element, and output element. Newly introduced in protective gear is transistor inserted between output of first comparator and capacitor of time-setting circuit. EFFECT: reduced probability of unwanted aftereffects caused by short-circuit currents. 2 dwg