Simplified Approach for Predicting the Starting Performance of Induction Machines Based on Rotor Design Modification

The starting characteristics of induction motors, largely determined by the rotor design, is a critical design factor from an end-users' perspective. The equivalent circuit model or finite element analysis (FEA) is most commonly used by motor manufacturers for the design to meet the specified starting performance, but is inaccurate or time-consuming. In this paper, a simplified approach for predicting the starting characteristics based on the equivalent circuit model and single-slot pitch 2-D and 3-D FEA is proposed. The influence of the radial cooling ducts, end bar extension, deep bar/skin effects, and magnetic saturation are taken into account for the accurate prediction of starting performance. The results of the proposed method are compared with conventional methods and verified through experimental testing on 6.6 kV and 522 kW induction motors. The results show that the proposed method is capable of providing fast prediction of the starting characteristics for the given rotor design without sacrificing accuracy.