Influence of deep bar effect on induction machine modeling with gamma-controlled soft starters

Direct line starting of induction machines causes high torque transients and inrush currents that can be attenuated using soft starters that adjust the applied stator voltage amplitude. Startup performance of the induction machine with a soft starter and gamma control strategy can be predicted much more accurately when deep bar effect is incorporated into the induction machine model. In this paper, a simplified, yet accurate deep bar effect model is presented in starting induction machine applications. The evaluations of the induction machine starting characteristics with and without considering the deep bar effects are conducted for both line start and soft start conditions. The gamma-controlled soft starter is described in controlling a 5 hp induction machine with the deep bar effects. Full time domain simulations for the line starting and the soft starting an induction machine have been implemented. Experimental results are presented to verify the improved simulation model, confirming the value of this analytical tool for practicing engineers