To avoid these ads, REGISTER NOW!

Eaton Mag Starter + Compressor Wiring Question

Lu-Max

Well-known member
Joined
Jan 8, 2014
Messages
745
I have a new Quincy QT-54 5HP (230V 1P) air compressor and I am adding an Eaton 5HP 230V magnetic motor starter (Eaton model# B27CGF30B040) to it.

I want to make certain I am wiring it correctly, so if you can verify (or correct) my plan it would be appreciated.

The setup:

I have a dedicated 30A breaker (#8 wire) circuit pre-wired to a wall-mounted, non-fused disconnect. From this disconnect I will bring 2 #8 hots and 1 #6 ground wire into the Eaton box.

One hot will go to lug L1 the other to lug L2. The ground will connect to the ground bus bar I will be installing (depicted as the green stripe for now). The yellow dial will be set to 30A.

The motor will be wired to lugs T1 and T3 with it's ground also going to the new (green) ground bus bar.

The one thing I am not certain about is which lugs on the pressure switch to run wires to which spades on the top of the Eaton relay?

I assume that I use just one side of the mechanical pressure switch, for example side (A), but then do I connect these wires to the two top, rear connectors in the Eaton box, the silver one behind L1 and the brass one behind L3? I'm about 99% sure this is correct.

Thanks for your help.

Eaton-Box-small_zpsuzetlq8i.jpg


eaton-pressure-switch-small_zpsncoarus9.jpg


pressure-switch-small-ab_zpsh8354hqy.jpg
 
Last edited:
To avoid these ads, REGISTER NOW!

kazlx

Well-known member
Joined
Oct 30, 2012
Messages
2,851
Location
Tustin, CA
You don't need the pressure switch wires to the motor, they just go to the mag starter instead. That is what controls the mag starter. The mag starter is just a giant relay. I have that exact box at home and can take a pic for you if you want.
 
OP
L

Lu-Max

Well-known member
Joined
Jan 8, 2014
Messages
745
You must not have read my text very carefully, I specifically talked about the switch wiring.

Also, thanks, but I've already looked at that diagram which was in another thread and it didn't answer my question.

It is not the same mag starter (mine doesn't have a heater strip) nor does it adequately show the pressure switch wiring which was my primary question. I have an L1 tab behind the L1 line in, an L2 tab that is directly connected to the L2 line in, and then a third L3 tab. The starter in this diagram does not.

So, do I connect it as I carefully outlined in the text in my first post?
 

kazlx

Well-known member
Joined
Oct 30, 2012
Messages
2,851
Location
Tustin, CA
You can always connect it with the power off and check it with a meter. You can push the mag portion down with a dowel or something to close it and check for continuity. I forget exactly how the trigger wires are supposed to go, but I can look at home. Same when I wire a relay, I don't do it often enough to remember which pole is which.
 
To avoid these ads, REGISTER NOW!
OP
L

Lu-Max

Well-known member
Joined
Jan 8, 2014
Messages
745
OK I have the pressure switch figured out using my continuity tester. I use both on the same side (A).

Now SPECIFICALLY which tabs do I run the wires from the pressure switch up to the top of the Eaton?

L1 Rear (silver)
L2
L3 Rear (brass)

Pick two please, that's the simple answer I need. I know that it is not the two front L1 and L2 (silver) tabs.
 
Last edited:
OP
L

Lu-Max

Well-known member
Joined
Jan 8, 2014
Messages
745
It's fully wired and ready to go, just need to know which tabs to coneect teh pressure switch to?
 

kazlx

Well-known member
Joined
Oct 30, 2012
Messages
2,851
Location
Tustin, CA
Sorry got side tracked with other ****. My pressure switch is wired to L1 and the terminal right behind it.

Come off the spade you have in yellow, go to the switch, then come back and go to the spade on L1.
 
To avoid these ads, REGISTER NOW!
Top Bottom