A fuse used to protect a motor against short circuits and overloads

A switch that only measures the current in a large power circuit

A transformer that supplies the control power to a starter panel

Motor controlsQuestion 80 of 1506

What is a contactor?

A fuse used to protect a motor against short circuits and overloads
A switch that only measures the current in a large power circuit
A transformer that supplies the control power to a starter panel
A relay used to switch a large amount of power, often to a motor

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Correct answer: A relay used to switch a large amount of power, often to a motor

Its contacts are usually normally open, so the load is off when the coil is de-energized.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 5.2: Contactors

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Questions last reviewed: 18 October 2026

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