CIRCUIT BREAKER WITH OVERTEMPERATURE PROTECTIVE GEAR FOR ELECTRIC MOTORS Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: circuit breaker has case with cover, trip-free mechanism, movable and fixed contacts with arc-control chambers, electromagnetic releases, control unit incorporating control divider unit with group of thermistors, their number depending on number of handled regions, as well as undercurrent release with power amplifier module, and transistor switch module in each pole of circuit breaker. Undercurrent release has in each pole of circuit breaker current transformer whose secondary winding is connected to input of transistor switch module. Outputs of transistor switch modules are interconnected in series and common point is connected to input of power amplifier module whose input is connected to circuit breaker final relay coil. EFFECT: reduced operating speed at high rate of temperature rise in phase windings of serviceable power circuits of motors. 3 cl, 3 dwg