Uranit Uran-isotopentrennungs-gmbh

Johann Mundt

A circuit arrangement for the automatic de-excitation of a hysteresis motor whose reactive power intake is compensated by capacitors and whose stator windings, which are fed from a three phase mains via a frequency converter, magnetize the rotor with their rotating field and thus produce a permanently magnetic excitation which continues in the rotor in the form of residual magnetic poles even after disconnection of the motor from the three phase mains. A voltage monitor monitors the mains side input to the frequency converter and responds upon interruption of the mains voltage due to malfunction or end of operation. Upon interruption of the mains voltage a capacitor of a buffer circuit in the d.c. intermediate circuit of the frequency converter transfers its stored energy, with decaying voltage, to the stator of the motor via an inverter which forms the output of the frequency converter, and upon response of the voltage monitor, the output frequency f.sub.0 of the inverter is automatically increased by a predetermined amount .DELTA.f, whereby the residual magnetism in the rotor is quenched.

Growing community of inventors

Julich-Koslar, Germany

Johann Mundt