Question 284Electricity & Electronics - Assistant Engineer

The correct answer is A) they reduce the voltage applied to the motor during the starting period. Autotransformer starters are used with larger polyphase induction motors to reduce the voltage applied to the motor during the starting period. This helps to limit the high inrush current that would otherwise occur, which could damage the motor or electrical system. By reducing the voltage, the autotransformer starter allows the motor to start more smoothly and gradually build up to full speed, rather than experiencing a sudden, high-current start. The other answer choices are incorrect because: B) increasing the voltage would not help with starting, C) autotransformers do not provide backup voltage regulation, and D) they only reduce the voltage, they do not allow for both step-up and step-down capabilities.