Auto-transformer starters, sometimes called starting compensators, are sometimes used with larger polyphase induction motors. What function do they perform?

Correct Answer: Option D — they reduce the voltage applied to the motor during the starting period

Auto-transformer starters utilize reduced-voltage taps to limit high inrush current during heavy polyphase motor start-ups, fully complying with 46 CFR Subchapter J provisions. Once the motor accelerates, full line voltage is automatically applied via running contactors.