Abstract: This article investigates the effect of winding short-circuit on the performance of the electrical/mechanical hybrid 4-redundancy brushless direct circuit torque motor (BLDCTM) in direct drive actuator (DDA). Based on the mathematic model of the electrical/mechanical hybrid 4-redundancy BLDCTM, the motor electrical parameter variations due to winding short-circuit are analyzed, and the equivalent circuit models are established for both interturn short-circuit and interphase short-circuit situations. The simulation results of the motor system demonstrate that the proposed low speed redundancy BLDCTM can ensure the normal executive functioning of the DDA when the interturn short-circuit in one of the phases or the interphase short-circuit between two phases occurrs. The electrical/mechanical hybrid 4-redundancy BLDCTM can overcome completely the effect of winding short-circuit and enhance the reliability of the DDA system.

Key words: brushless direct circuit motor, redundancy, actuator, interturn short-circuit, interphase short-circuit