Analysis And Calculation Of Stator End-leakage Reactance For Induction Motors With Low Harmonic Windings

The design and development of energy-efficient motor has a very importantrole in the implementation of the national energy conservation policy. Withoutincreasing manufacturing costs, the application of low harmonic windings is ameasure to improve efficiency and performance of motor, reduce temperature rise,and save the amount of copper; the effect of energy conservation is very obviouson medium and small size of2-pole motors. The construction features of lowharmonic windings is the presence of single-layer windings and double-layerwindings simultaneously, the end portion of windings is tied together inaccordance with the flow direction of the current in slots, the shape of endportion of windings is similar to the shape of end portion of concentric windings,which is very complex. The traditional electromagnetic calculation method cannot accurately calculate the value of the stator end-leakage reactance.From the point of view of the energy method, firstly the stator end-leakagereactance formula is derived. Based on the finite element method, end leakagemagnetic field of low harmonic winding asynchronous motor is analyzed andcalculated, which is used by Ansoft software. The magnetic energy is solved, andstator end leakage reactance is calculated according to the results of thenumerical analysis. Combined with indirect test method and the traditionalmethod, which are used for stator end-leakage reactance analysis, through theanalysis and comparison of the calculated results, the calculation method of theend magnetic field of low harmonic windings has a high accuracy.The expression of stator end leakage reactance leakage permeability isachieved by the results based on the finite element method, which is suitable and available for engineering calculation. Different types of winding arrangement andthe corresponding change of the current, the length of the end windings, and thedistance between cover and end windings have a huge impact on the distributionof the end leakage magnetic field. Based on the experimental data, the curves ofrelationship between these factors and the stator end leakage reactance areachieved. For engineering optimization design of low harmonic winding providecertain reference.