Magnetic starter troubleshooting

[flan]

Looking for a little help troubleshooting my newly installed compressor with magnetic starter. I installed my used compressor (Saylor-Beall, 5hp motor single phase) with a new magnetic starter (https://compressor-source.com/produ...ic-air-compressor-motor-starter-switch-msp30t).

1 hot going to 1L1
1 hot going to 5L3

1 motor wire going to 6T3
1 motor wire going to 2T1

1 pressure sw wire to 1L1
1 pressure sw wire to A2

So the problem is the starter makes a humming noise, loud enough to hear through the plywood floor from below, and the compressor does not run. I manually pushed in the contactor on the starter, and the compressor ran, but ran slow. When I released the contactor the compressor stopped and the starter stayed humming.

So there is the story, any ideas where to start looking for the problem would be appreciated!

 

[toplessHO]

might help to fill in a few blanks
voltage,phase,single or 3ph
properly sized heaters installed?
voltage for contactor coil?
If single phase and coil is 120V wheres the neutral?
It sounds like coil has low voltage and isnt pulling in properly.
The control circuit for coil voltage should run thru the overload heater circuit and the pressure switch.

 

[flan]

might help to fill in a few blanks
voltage,phase,single or 3ph
properly sized heaters installed?
voltage for contactor coil?
If single phase and coil is 120V wheres the neutral?
It sounds like coil has low voltage and isnt pulling in properly.
The control circuit for coil voltage should run thru the overload heater circuit and the pressure switch.

Single phase.
It’s 240v.
And I’m an idiot.
I had 3 wire hanging around so I used it. Upstairs I used white and black for the hot wires, downstairs at the panel I hooked up red and black to the breaker. Was only getting 120v. Problem solved she is running good now.

 

[wyliesdiesels]

So you hooked the white wire to neutral bus?

I would just disconnect it to cut down on confusion as motor doesnt need a neutral.

 

[toplessHO]

He didnt state what voltage the coil was,so if 120V and it doesnt have a control Xmr he will need that neutral.
Yikes on the white being hot and you didnt know it. Hope it was capped off.

 

[wyliesdiesels]

He didnt state what voltage the coil was,so if 120V and it doesnt have a control Xmr he will need that neutral.
Yikes on the white being hot and you didnt know it. Hope it was capped off.

white was NOT hot and couldnt have been since he used black and red at the panel to connect to the breaker.

The white wouldve had to have been connected to neutral because the coil and starter were getting 120v. So the white was neutral.

 

[mm08822]

He didnt state what voltage the coil was,so if 120V and it doesnt have a control Xmr he will need that neutral.
Yikes on the white being hot and you didnt know it. Hope it was capped off.

There would 2 cases if the "white being hot".
1) neutral at same potential as other side of coil = 0 volts across coil. It would not have pulled in or hummed.

2) Neutral was hot (relative to other side of coil) - the coil would have pulled in. No humming. Motor would have had 240 vac and started w/o issue.

Since the coil only chattered/hummed, it is easy to figure 120 vac applied to a 240 vac coil somehow. So the troubleshooting plan becomes check voltages to starter / to coil.

 

[flan]

So you hooked the white wire to neutral bus?

I would just disconnect it to cut down on confusion as motor doesnt need a neutral.

Yes! Brain was thinking like I was wiring 120. I’m not an electrician

Now red and black are hot, and white is trimmed back short where the wire enters the breaker box and mag starter so there can’t be confusion ever again.