Soft Starting of High Power Three Phase Induction Motor: Theory and Applications

Abstract

In most heavy-industry, three-phase asynchronous motors have become an inevitable piece of equipment that transforms electrical into mechanical power due to their simple and reliable structure. One major problem with the high-power motor is starting, since direct-on-line starting of high-power motors usually cause voltage sag and over-current which may affect other equipment in the same network. Besides, most heavy machines are sensitive to high acceleration and jerking of mechanical parts. So, having a thorough understanding of soft starting solutions for high-power three-phase asynchronous motors is extremely important to electrical engineers. In this research, the most being-used soft-starting solutions of three-phase induction motors are reviewed with in-depth analysis. Based on numerical simulations carried out with the two most popular loads: pump/fan and dry-friction, the reader can see the effectiveness of each soft-starting method intuitively.