How Soft Starters Protect Electric Motors

Some electric motors draw a large surge of current when they start up, far more than they need at normal operating speed. This surge, called inrush current, creates a spike in torque that can stress and damage motor components and connected equipment. Soft starters exist to solve this problem.

What a Soft Starter Does

A soft starter gradually increases the voltage supplied to the motor during startup, which limits inrush current and ramps up torque smoothly rather than all at once. The same principle applies during shutdown, the soft starter can ramp voltage down gradually rather than cutting power abruptly. The result is a smoother, more controlled start and stop.

Why It Matters

The practical benefit is reduced wear on motors, couplings, and driven equipment. Abrupt starts put mechanical stress on everything connected to the motor shaft. In a refinery where motors drive pumps, compressors, and fans that run continuously for years, that stress adds up. Soft starters help extend equipment life and reduce the frequency of repairs.