Three-phase AC induction motors have become a norm in almost every industry due to their wide number of applications. However, directly connecting them to the power source is not an option due to their unique starting characteristics. A direct start can cause a huge surge current to flow into the motor—almost 6 times its rated capacity. This can put strain on the supply lines as well as the motor’s internal structure.

In order to eliminate this problem, several methods have been created throughout the years—some involving autotransformers, some reactors, and so on. Modern electrical and electronics components have produced a comprehensive solution to all kinds of motor-starting problems known as soft starters.