COMPUTATIONAL MODELING OF THE SQUIRREL-CAGE INDUCTION MOTOR STARTING PROCESS Dr. Saleh Al-Jufout Tafila Polytechnic, Al-Balqa' Applied University, P.O. Box 179, Tafila 66110, Jordan. Tel.: +962.3.342326, Fax: +962.3.342327 E-mail: Tafil_cc@amra.nic.gov.jo Abstract – This paper presents a methodology for computational modeling of the induction motor starting process. The numerical model of the squirrel-cage, three-phase induction motor is represented as a system of differential equations. The model takes in account the skin effect, transformation and rotational electromotive forces and it can give the instantaneous significant of required modes’ parameters. The dynamic curves of the motor phase current, speed, active and reactive power and electromagnetic torque during starting process are obtained. The torque-speed and current-speed static characteristics are also obtained. INTRODUCTION In electric machinery course it is very essential to simulate some experiments that occur rapidly and might be dangerous or expensive, the necessity appears when performing them by students. Therefore, simulation enables students grasp the theoretical concepts of these experiments. Motor starting process is one of the most important experiments in electrical engineering education, but it occurs within few seconds that makes it difficult to be observed. Simulation of this process permits to observe how the variables (current, torque and velocity) change during this process and compare different type of motors on the personal computer display. Judged in terms of fitness for purpose coupled with simplicity, the induction motor must rank alongside the screwthread as one of mankind's best inventions. It is not only supremely elegant as an electromechanical energy converter, but is also by far the most important, with something like one third of all the electricity generated being converted back to mechanical energy in induction motors. Despite playing a key role in industrial society, it remains largely unnoticed because of its workaday role in unglamorous surroundings driving machinery, pumps, fans, compressors, conveyors, hoists and a host of other routine but vital tasks. It will doubtless continue to dominate these fixed-speed applications, but thanks to the availability of reliable variable-frequency drives, it is also now will established in the controlled-speed arena. Deep-bar or double-cage rotors of the induction motor have a high effective resistance at starting and a low effective resistance under normal running conditions, thus yielding both a high starting torque and good speed regulation in the same motor (Stephen J. Chapman 1991). Therefore, studying its dynamic and static characteristics is of a great importance. THE NUMERICAL MODEL OF THE INDUCTION MOTOR The numerical model of the three-phase, squirrel-cage induction motor is represented as a system of differential equations written in α, β rectangular coordinates (Jukov 1994). To take in account the skin effect in the deep-