Is it acceptable to use a general purpose relay (which does not have a HP rating on it) to start and run a fractional hp motor (up to 1/2 hp) ? The motor will have built in automatic overload protection. The relay would have a higher rating than the motor amperage.
Or do 1/4, 1/3 and 1/2 hp motors have to be started using a horsepower rated contactor?
Thanks for your time.
I have always used a HP rated contactor/starter for all motor applications. The inrush on a motor can be 6 times the running amps. Burning up a contactor because of the starting current is just silly to me. There are some "ice cube" relays that are HP rated that do not cost very much.
Not knowing your application it is impossible to offer constructive suggestions.
Use a HP rated contactor. There is no guarantee about the contact life on a resistive rated contactor with a motor load. Those are intended for resistive loads such as heaters.
Ben Miller
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