VARIABLE-SPEED ELECTRIC DRIVE WITH UNCONTROLLABLE DC SECTION Russian patent published in 1996 - IPC

FIELD: speed control of industrial mechanisms. SUBSTANCE: introduced in variable-speed electric drive with uncontrolable DC section are controlled switch 8, current limiter 6, voltage limiter 7, harmonic signal shaper 14, emergency protective unit 21, OR gate 3, display unit 24, motor current phase unbalance sensor 22, motor temperature sensor 23, supply voltage sensor 9, inverter input voltage sensor 10. All these newly introduced parts provide for motor speed control under starting, running, and braking conditions in comprehensive speed control range, high power characteristics due to improved waveform of supply voltage current, current limiting at desired level, automatic disconnection in case of excessive voltage, current, temperature, supply voltage dip, unbalance of motor phase currents. EFFECT: improved reliability of speed control. 6 dwg