What is the primary distinction between a contactor and a motor starter?

The primary distinction between a contactor and a motor starter lies in the functionality and components associated with each device. A contactor is fundamentally an electrically-operated switch used to control a high-power circuit. It is designed to simply turn on and off electrical loads, typically in larger systems. However, it does not include built-in protection mechanisms for the motor, such as overload relays.

On the other hand, a motor starter incorporates additional protective components, most importantly overload relays, which protect the motor from overheating due to overload conditions. These overload relays monitor the current flowing through the motor and interrupt the circuit if the current exceeds safe levels, preventing potential damage to the motor.

This distinction underscores that while all motor starters include a contactor as a component, not all contactors have overload relays. This is a fundamental understanding of their respective roles in electrical systems, particularly in motor control applications.