Slot-Combination Selection Method For Single-Winding Two-Speed High-Power Cage Induction Motors

For high-power single-winding two-speed motor, how to select proper slot-combination with the station of straight slot to improve the efficiency, starting performance and vibration noise is still a problem. Considering test verification is difficult to realize for high-power motor, and the influence of slot-combination changes on small and medium motor is the same as on high-power motor, this thesis takes a 15/3kW,4/8 poles single-winding two-speed motor as an example for demonstration, and the conclusion is suitable for high-power motor. This thesis through a combination methods of theoretical analysis, simulation and experimental study for the influence of slot-combination changes on magnetic field, efficiency, starting performance and exciting force of the motor. The main works are summarized as follows:Firstly, taking a 15/3kW,4/8 poles single-winding two-speed motor with 48stator slots as an example, this thesis analyzes the magnetic field of the motor with the different slot-combinations in both no load and load situation of two poles by establishing motor ANSYS models with different slot-combinations and Time-Step Finite Element Method, and summarize the regularities of magnetic field changes.Secondly, based on the analysis of the magnetic field, taking into account the no-load and load situation of the motor with different poles, the thesis gives a detailed analysis on the law of the iron loss, stator copper loss and rotor copper loss changes when the slot-combination changes and finally verified by experiment.Thirdly, the thesis studies the influence of slot-combination on the starting performance of the motor by magnetic field analysis. By contrasting the starting torque and the T-s lines of the two-speed motor with different slot-combinations in different poles, this thesis proposes several slot-combination schemes that benefited to motor starting.Finally, this thesis analyses the exciting force of the motor when the slot-combination changes, and summarized the vibration and noise of the motor combined with the inherent frequency of the motor, and then gives the method of slot-combination choice to reduce the noise and verified by experiment.This thesis studies the influence of the slot-combination on loss, starting performance and vibration noise of the motor, and provides a basis and reference of slot-combination selection for high-power single-winding two-speed motor.