Motors larger than fractional horsepower use what to start and stop?

• A. Motor Starter
• B. Control Relay
• C. Soft Starter
• D. Motor Controller

Answer: (A)

Starting and stopping large motors safely requires a device that can handle high current and protect the motor. A motor starter is designed for this purpose: it combines a contactor to switch the motor on and off with an overload protection device to trip if the motor overheats or is overloaded. This setup allows remote control from a switch or automatic control system and provides the necessary protection for motors larger than fractional horsepower.

Soft starters are used to ramp voltage and limit inrush during startup, which is useful for reducing mechanical stress, but they’re not the standard device for simple on/off control with protection. A control relay can control circuits but isn’t sized to switch heavy motor current or provide motor protection. A motor controller is a broader term and isn’t as specific as “motor starter” for the typical on/off control with protection required for larger motors.