Circuit arrangement for regulating the rotation speed of an electric motor

摘要

The invention relates to a device for regulating the rotation speed of an AC or three-phase motor which has a main winding and auxiliary windings. The control circuit, which takes into account an external state variable, is connected only to the main winding. This results in the motor, for example a pump motor, continuing to run even if the control circuit controls the supply voltage down to virtually zero. <IMAGE>