Instability and Imbalance Response of Large Induction Motor Rotor by Unbalanced Magnetic Pull

Abstract

This paper deals with a general analytical method for analyzing the instability and mechanical imbalance response of induction motors considering unbalanced electromagnetic forces produced in the induction motors with rotor eccentricity and phase unbalance. The equations to be solved are a set of second-order differential equations that give matrices with periodic coefficients that are a function of time due to the unbalanced electromagnetic force. The evaluation method of rotor instability zones is presented by a time transfer matrix method. The Newmark β method is adapted to solve for an imbalance response. A practical application is given for a large induction motor. The results show that the proposed method is satisfactory.

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