Effect of laminated rotor core stiffness on the vibrational behaviorof squirrel cage induction motors

Rotor core stiffness effect on dynamic response ofinduction motors is one of the most challenging subjectsin the recent studies. As stacked rotor core shrinks directlyon a shaft, its strength to bending affects the shaftstiffness, and has a significant effect on naturalfrequencies of the rotor. In this research, two isotropic andorthotropic model for rotor lamination behavior ispresented. Also, experimental modal test has beenperformed on the rotor and natural frequencies and modeshapes obtained. Orthotropic properties of the stackedcore are determined by try and error and comparison withexperimental results, to minimize the deviation ofcalculated natural frequencies. Results show that theorthotropic properties for rotor stack is more accurate thanisotropic one. In the next step, stiffness of bearings isdetermined under applied static load. After that, based onthe approved stacking model, a finite element modalanalysis of motor is implemented and natural frequenciesand mode shapes are reported. Finally, mass unbalanceresponse for each motor bearing is executed.

Effect of laminated rotor core stiffness on the vibrational behaviorof squirrel cage induction motors Keywords:

stacked rotor , natural vibration , inductionmotor , modal test.