Switching configuration for electric motor, has current limiter to facilitate safe separation of holding wires at electrical connection between evaluation unit at static frequency changer and sensor unit at electric motor

摘要

A current limiter (4), with a pair of serially connected current limiter elements (11,12), is provided at the electrical connection (5) between an evaluation unit (2), provided at a static frequency changer (7), and a sensor unit (3), provided at the terminal box (10) of an electric motor (6). The limiter safely disconnects the holding wires (8,9) at the electrical connection, when overloading or overheating temperature is over the limiter rating temperature. The saturation current at the limiter rating temperature is over 10 milliamperes and drops at time of overloading.