SECONDARY THYRISTOR CONTROL FOR AC WOUND ROTOR MOTORS

摘要

A control system for polyphase AC wound rotor motor which employ controlled thyristors in a delta secondary circuit network together with series connected resistors. A variable frequency and amplitude AC reference signal is derived from the motor secondary terminals, and processed so that it will provide gate firing currents that are insensitive to inherently generated erroneous zero crossings of such AC reference and is correctly tuned in relation to motor speed and torque requirements. The system is disclosed in conjunction with an AC wound rotor motor designed for use in an industrial hoist drum that additionally employs an eddy current retarding brake.