motor control wiring

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JES2727

Senior Member
Location
NJ
Today I wired up an industrial mixer. It was 1.5 hp, 3 phase, 208v. I used an Allen-Bradley size 0 starter with a 120v coil. I pulled a neutral along with the circuit to use for my control circuit. For my control wiring I connected one wire to the line side of the starter, hit the limit switches (so the mixer won't start without the kettle being in place), hit the stop/start, and then came back and connected to the holding contact, o/l relay, etc. and then to the coil. I landed the neutral directly on the other side of the coil. The in-house maintenance man at the facility suggested I use a 208 to 120 transformer to originate my control circuit. When I asked him why he said "That's the way it's done". He was so convincing, I decided to go ahead and do it my way. But of course I'm wondering, is there any reason to do it his way? What do you guys think? Also, should I have fused the control wiring? There is no load on it other than the coil (no indicator lights or buzzers, etc.). I installed 10amp FRN-R fuses upstream of the starter. The nameplate rating of the mixer is 5.8 amps at 208v.
Thanks for any input.

John
 

benaround

Senior Member
Location
Arizona
Re: motor control wiring

John,

"I landed the neutral right on the coil"

John, I've seen this done so many times. The neutral has to land on one of the terminals that the OL's control and the other side goes to the coil. That way if the overload circuit kicks out the coil looses the neutral and opens the contactor,by running the neutral directly to the coil you have no overload protection for the load.

About the transformer,IMO the way you did it is fine 120/208 circuit
 

JES2727

Senior Member
Location
NJ
Re: motor control wiring

Thanks Frank. I should have been more specific. I didn't alter any of the factory wiring on the starter. I landed the neutral on a terminal downstream from the o/l relay and the coil. In other words, the o/l is between the coil and the neutral connection.
 

benaround

Senior Member
Location
Arizona
Re: motor control wiring

John,

Thats good to hear! I don't know why,but a lot of guys will land it right on the coil?

Happy motoring.
 
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