Electrothermal And Thermal Stress Distribution Calculation And Analysis Of Induction Motor With Compound Cage Rotor

Induction motor with compound cage rotor (IMCCR) was designed for overloadstarting and light running occasion. Rotor slot of IMCCR consists of two parts,one part is made from conductive and magnetic alloy material, another part is madefrom conductive cast-aluminum. The structure and materials of rotor slot achievebetter starting performance of IMCCR and running performance. In this paper, twotypes of IMCCR are based on the prototype of IMCCR, these two types of IMCCRbars include compound bars and cast-aluminum bars, compound bars andcast-aluminum bars are arranged alternatively in the rotor core. The paper analysesthe electrothermal performance and thermal stress distribution calculation of twotypes of IMCCR.Firstly, the main characteristic of the IMCCR is that the part of rotor bar is madefrom alloy materials, so the IMCCR performance requirement of the alloy materialsis higher. Mixing component of alloy materials evenly is demanded in the process ofproducing the alloy materials. In the test performance of conductivity andpermeability on alloy materials, averaging test values of repeated measurements isrequired to improve measurement precision.Secondly, the starting and running performance are calculated by finite elementmethod. The test sample are prototype and two types of IMCCR. The experimentaltests and results on a full-scale prototype of IMCCR starting and runningperformance are reported to verify the accuracy of this calculation method. Thecalculated values of prototype are compared with other types of IMCCR. Calculatingslot leakage reactance on prototype and two types of IMCCR Starting is necessary aswell as the relative permeability of alloy bars when starting and running, the paperanalyses the factor of relative permeability change on alloy bars when starting and running.Thirdly, experimental tests and results on a full-scale prototype of IMCCRtemperature field are reported to verify the accuracy of this calculation method. Thepaper calculates the temperature field on two types of IMCCR. After comparingfull-field temperature and all parts temperature on two types of IMCCR, theperformance of heat transfer on two types of IMCCR is analyzed.Finally, based on heat transfer and mechanics theory, the thermal stressdistribution on rotor of two types of IMCCR is calculated. The paper analyses thethermal stress distribution on bars of two types of IMCCR and extracts thermal stressvalues on compound bars and cast-aluminum bars of two types of IMCCR. Thereasons which affect the thermal stress distribution bars of rotor are investigated.