The Right Way To Wire A 120V AC Motor

Hi Every One,

Just want to make sure i am doing this the same way as every one else. For 120v AC motors (5 amps) are you using starters or relays to control them?

I am buliding a new panel and curently they are using relays. But some of our lines have starters in them (Same Manufacture, same line, 3 years apart).

BTEACHMAN, as a rule I have always used starters. The contacts are more durable and you can utilize overloads as protection. The cycles required per event and the type of load may also be a deciding factor. More details would help.

A relay only has 1 contact.
A Starter or Contactor has 2 contacts (double-break). An inductive load such as a motor can weld contacts. With a double-break contact, if one of them welds, the mechanics are designed so the contact will pivot and break the weld. Notice the contact is sitting on a spring and floating.

Sometimes the lines are blured between relay and contactor. If they call it a relay, but it has the type of contacts that can self-clear a weld, then it's really a contactor and safe for motors. I've seen single contact contactors (30 amp) that had floating contacts.
When in doubt, use a device that has a double-break contactor. If it's called a starter or a contactor, that should be the case. Also, check for a horsepower rating in addition to an amp rating. That indicates it's designed for motors.
I would use an IEC contactor with a 5 HP single phase (or larger) rating.

Relay contacts have ratings in HP and in amps if they are motor rated. We use relays all the time for small single-phase AC motors. Class 92 relays are good for 1 HP and 30 amps at 120VAC. I have never had a problem with one.

I looked at the W92 series from Magnecraft. Looks good to me. Thank you.

I use relays for motors that have internal thermal protection, starters for those that don't