Wiring control box with IEC starter - Help Requested

I'm building out a control box for a machine I recently acquired. Original wiring was hacked up pretty badly by previous owner so I decided to start fresh and add modern safety stuff to this machine which was designed to use a simple disconnect to start the motor.

230v 3ph coming in off a rotary.

I have the disconnect wired and power running to the starter but this is where I begin to be confused and no amount of youtubing has resolved some of the simple questions I have.

I'm using a starter designed for 120v controls and so I am picking up 120v off L1 and running it to the NC side of the push button stop then over to the E-stop NC. This wire then goes to the NO side of the start and finally over to NO(13) on the starter.

I am confused at this point, my understanding is that I run a wire from the other side of the NO(14) over to A1 (coil), then from A2(coil) to 95 (overload). From 96 (overload) to source power. What’s confusing me is where a neutral comes in to complete these circuits? Otherwise I’m just running hots to either side of the circuit? Doesn't make sense to me, am I just running these to chassis ground?

Thank you!
Brian

Three phase has no neutral. If you need 120 for the control circuit you will need a transformer, 230/120. Wire the high side of the transformer to 230, but use only use the two wires into the rotary from distribution box. DO NOT use the generated leg. The voltage is unstable and will cause problems. On the secondary side, connect one wire to the NC (stop) PB, from there to the NO (start PB) from there to A1 (coil), from A2 (coil) to OL relay, from OL relay (95) from OL relay (96) E-stop to other side of transformer. This end of the transformer should also be grounded to the enclosure.

motor starter circuit - Google Search

Tom

If you are determined to use the existing 120 volt coil, would it be possible..in the off chance you have pulled a neutral into the line side of the RPC, to use that for a 120 volt supply for the contactor. This would only be feasible if you had the neutral their, along with your ground and two hot legs. Not something one would do normally.

Much easier to put a 240 volt coil into the mag though!

Stuart

atomarc said:

If you are determined to use the existing 120 volt coil, would it be possible..in the off chance you have pulled a neutral into the line side of the RPC, to use that for a 120 volt supply for the contactor. This would only be feasible if you had the neutral their, along with your ground and two hot legs. Not something one would do normally.

Much easier to put a 240 volt coil into the mag though!

Stuart

Click to expand...

Not necessarily. One of the reasons IEC contactors are low priced is that they lack a lot of the features of US controls and among those is easy coil change.

TDegenhart said:

Three phase has no neutral. If you need 120 for the control circuit you will need a transformer, 230/120. Wire the high side of the transformer to 230, but use only use the two wires into the rotary from distribution box. DO NOT use the generated leg. The voltage is unstable and will cause problems. On the secondary side, connect one wire to the NC (stop) PB, from there to the NO (start PB) from there to A1 (coil), from A2 (coil) to OL relay, from OL relay (95) from OL relay (96) E-stop to other side of transformer. This end of the transformer should also be grounded to the enclosure.

motor starter circuit - Google Search

Tom

Click to expand...

Thanks, Tom. I guess my misunderstanding here is that I assumed using 120v for the coil would mean that I could take one leg off of the incoming lines to accomplish that. Sounds like that won’t work so I’ll go ahead and pickup a transformer.

Would this transformer perform the task?

McMaster-Carr

Thank you
Brian