Autotransformer starter of three phase induction motor

An autotransformer starter reduces the voltage applied to the motor during starting using taps on a transformer.

⚡ Purpose of the Autotransformer Starter

• Reduce starting current (typically to 30–70% of direct-on-line current)
• Reduce starting torque (which is proportional to the square of voltage)
• Protect both the motor and electrical network during start-up