A control circuit for a reluctance machine having two mutually movable parts and at least one inductive phase winding adapted for a certain maximum drive current value. The protective sheet has a surface resistivity between 1. Each outer terminal of the first conductor member group is displaced from a corresponding one of the outer terminals of the second conductor member with respect to the circumferential direction of the first conductor member group. A release operation unit is kept by a worker who removes the safety plug, so that safety of the worker against electric shock is ensured.