Relay / Contactor Info

[Jim]

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.

 

[SQLit]

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.

 

[Ben Miller]

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.

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[/QUOTE]