Question

I need to start and stop a motor; I am confused on what the difference between an MSP, starter, and contactor are?

Answer

The contactor is the basic denominator in this equation. It is nothing more than an electric switch or relay. When one uses overload relays (heaters) or an MSP (motor starter protector) in conjunction with a contactor, it becomes a starter.
The conventional method is a contactor on top and an overload unit below.
The alternative method is to have the manual starter (MSP) on top as the overload, with the contactor on the bottom. The MSP is always closed and will perform the same duty as the conventional overload unit previously mentioned.

The MSP by itself acts as a manual motor starter. Starting the motor without the aid of an electric control coil or relay; simply by depressing the local start push-button.

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FAQ Subcategory: None

This item was last updated on 2004-02-18
Document ID: 840

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