Safety chain

In case of safety relevant faults (such as exceeding maximum high pressure or overstress of the motor), the frequency inverter must immediately be switched off. For this emergency switching off, a customary electronic regulation is not sufficient. Suitable safety measures are e.g. a main contactor between the frequency inverter and motor, which can immediately cut off the current supply.

A more advantageous option is a frequency inverter with safe torque off (STO) (e.g. Bitzer Varipack) with approved integrated connection in the safety chain according to EN61800-5-2.