HIGH-SENSITIVITY PHASE-TO-PHASE SHORT-CIRCUIT PROTECTIVE GEAR FOR ELECTRIC MOTORS

摘要

FIELD: protection of induction motors against phase-to-phase short-circuits. SUBSTANCE: protective gear depends for its operation on current cut-off; novelty is introduction of reduction unit for motor current being measured and generator running detection unit. Block-diagrams of motor current decay unit and of unit for detecting motor running as generator as well as curves characterizing effectiveness of protective gear are given in description of invention. EFFECT: enhanced sensitivity of protective gear without impairing its selectivity and speed of response. 21 dwg, 1 tbl