Winding Designing Of Pole Changing Two-Speed Motor And Research On Combination Of Slots And Additional Torque

The high-voltage pole-changing two-speed motor is regard as an energy-saving device for driving the loads such as fans or pumps. With the concern of energy crisis, it has taken a more and more important role in the thermal power station and oil exploration fields. That demands the pole-changing two-speed motor with high performance and high capacity. In designing this kind of motor, the critical part is the design of stator windings. Herein, we designed multistar phase-shifted pole-changing motor windings with the following advantages, for example, high utilization, less outgoing head, simple chang-over switch and stable performance after pole changing. It has a great potential applications in the near future.In this paper, we systematically investigates three types of arraged program of3Y/3Y phase shifted pole changing windings by using phase shifted pole changing method. The most practical arranged program is seleted by calculating the angle slip and degree of unbalance. Futher, this arranged program is optimized through winding hannonic analysis and the gap flux density proportion calculation. The optimal pitch under two poles is obtained based on above results. According to the circuit model of motor, the method, which is used for calculating loss in stator windings of multi-star phase shifted pole changing motor, is given. In accordance with electromagnetic theory, the mathematical model of two-dimensional electromagnetic field for pole-changing motor is established. Using time-step finite element method, distribution of branch current and extra loss in stator windings are simulated in the case that the branch is unbalance. We compare above calculations to verif its accuracy. Several arranged programs with differerent unbalance degree are got by the method of losing the winding or changing the vector position of each phase. And their extra no-load losses in stator winding are calculated. The degree of unbalance factor as a new concept is proposed and summarized its calculation method. The relationship of the extra no-load losses in stator windings, the degree of unbalance and the degree of unbalance factor is analyzed and discussed.In order to make the motor with excellent safety starting performance, the influence of the combination of stator and rotor slot on extra torque is further studied. The equivalent circuit model of the asynchronous motor which contained the harmonics is given. The asynchronous extra torque of the motor, which have three kinds of combination stator and rotor slot, is given by calculation according to formula mentioned in the paper. Combining with the synchronous extra torque generated condition, the above calculation results can be used to determine the emergence of synchronous extra torque of the motor with three types of stator and rotor slot motor. Base on the above analysis calculation results, the optimal arrange program with high-voltage pole changing two-speed motor is given.