Electromagnetic,Temperature And Thermal Stress Distribution Calculation And Analysis Of Induction Motor With Compound Cage Rotor

Induction motor with compound cage rotor (IMCCR) is a new type of inductionmotor designed on beam pumping unit and screw pumping unit such as overloadingstarting or light load operation occasion. The special slot is adopted in compoundcage rotor. Conductive and magnetic alloy material and cast aluminum are used inthe upper rotor cage bar, the lower cage only adopt cast aluminum. In the process ofpreparation of alloy cage bar material, a phenomena of uneven distribution ofmaterial may happen, there is the differences of iron and copper content in differentregions of the alloy, there may be rich iron area and rich copper area at the same time,that could make Fe and Cu to be layered each other in the alloy, not generate metalcompounds, but maintain their different form. Non-uniform doped copper iron alloymaterial directly affects the magnetic permeability and electric conductivity, and theninfluence on the starting and running performance of the motor. Therefore, in orderto study the effect of the motor starting and running performance resulted from theuniformity and nonuniformity of the alloy material, the extreme forms of physicalmode of the non-uniform doped copper and iron material is put forward, and hascarried on the theoretical research.The starting and running performance of two kinds of motor being unevendistribution copper iron alloy are respectively calculated by the finite elementmethod, the influence of magnetic field distribution of motor and rotor conductingbar electric density resulted from uneven distribution alloy are analyzed. Rotor slotleakages of two kinds of the motor starting are calculated, the influence of slotleakage reactance generated by uneven distribution alloy material and then theeffects on the motor performance are analyzed.For the phenomenon of copper iron stratification in the alloy, the two-dimensional steady-state temperature field distribution is studied when the motorwith the uneven distribution copper iron alloy is at stable operation, andcompared with the calculation results of the prototype.Finally, due to the cause of the small induction motor often appearing the faultof the rotor broken bar, internal thermal stress distribution of induction motor withcompound cage rotor is calculated and analyzed on the basis of heat transfer andmechanics theory, and compared with internal stress distribution of the sameordinary cage induction motor rotor, which showed that rotor internal stress ofinduction motor with compound cage rotor is less than ordinary cage induction motor.Rotor internal stress distribution is further calculated for of two kinds of IMCCRwith uneven alloy material, and a greater influence on the temperature and stressdistribution of the motor rotor is found when the alloy material distribution is seriousuneven.