A static 300 V-75 A DC self-protected contactor using a new power component MCT

This paper describes the design of a static 300±10% V-0 to 75 A DC self-protected contactor with 85 A “magnetic tripping” and 100 A interruption current at 2.2 A/μs short circuit of load condition using a new power device the HARRIS MCT (600 V-75 A). The classical ZnO varistor for energy absorption and turn-off snubber circuit (“C” or “RCD”) of the MCT are replaced by a new semiconductor system, the active energy absorption device. This system gives more efficient turn-off snubber circuit action and low controllable clamping factor without the disadvantages of ZnO such as high clamping factor and transient peak overvoltage at the beginning of clamping