Design of the new motor operating mechanism for 40.5kV vacuum circuit breaker

Based on mechanical load characteristics of opening and closing operations of 40.5kV vacuum circuit breaker, a new type of permanent magnet brushless DC motor operating mechanism is designed. The main structural sizes of the drive motor are calculated by using the target value method. Through analyzing the performance of the same volume motor under different winding wire diameter and number of turns, the scheme of winding wire diameter and turns — more output torque, faster motor rotational speed, higher power density — is determined. The overall design of the drive motor is completed. The mathematical model of the motor is established with finite element theory. The dynamic rotational angular displacement and output torque of the motor are obtained. Compared with the pre-existing motor operating mechanism, the volume of new drive motor is reduced by 23%, and the average output torque and rotational speed can be increased by 53.4 N·m and 38 r/m respectively.