A Numerical Investigation of Inrush Current Reduction in Induction Motors

Induction motors are the most commonly used machines in industries and homes mainly because of its robustness, low cost and easy to maintain. The starting current of induction motors is usually higher than the rated current and this persists for a few cycles which may be detrimental for the machine operation. This paper focuses on the reduction of the starting current using soft starter to limit the inrush current. This paper focuses on the reduction of the starting current using soft starter to limit the inrush current. In accomplishing this task, a design and implementation of a soft starter was carried out using components comprising two Silicon controlled rectifiers (SCRs) which were connected in anti-parallel, contactors, relay, resistors and other electrical and electronic integrated circuit components. The result was achieved by successfully testing the soft starter on a connected single phase induction motor. There was a gradual increase of the voltage during the motor startup which allows the motor to slowly gain speed and acceleration thereby preventing mechanical tear and jerking when the soft starter was applied