RELAY PROTECTIVE GEAR FOR INDUCTION MOTOR

摘要

electrical engineering; automatic control of induction motors. SUBSTANCE: newly introduced in relay protective gear are active frequency band filter for discriminating fundamental harmonic of secondary phase currents of induction motor and counter that functions to scale down supply frequency of 50 Hz to 1 Hz; signal arriving from this counter provides for determining permissible operating time in microcontroller from moment of load connection to motor stopping time as function of phase- to-rated current ratio. EFFECT: enhanced precision and efficiency of protective gear under transient conditions. 1 dwg