Rewiring Air Compressor Control - solution, see last post

ctfjr

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The previous owner of our hose left me a nice Ingersoll-Rand air compressor. I also left my air compressor in our old house for the new owners.

The compressor is in the basement with 2 air lines going to the garage upstairs and 1/2 down the basement to where he used to do old car restorations. I lengthened the basement air line to reach my workshop, next to where the tractor sometimes sleeps. Next I had to set up a control system where I can turn the compressor on and off from either air terminal location. I did that at the old house.

It's a pretty easy project. Run 3-way switches (SPDT) with 3 wire from each location, 18 ga thermostat wires. I took a nice size j-box and put a 230 to 24 volt transformer and a large contactor with a 24 v coil. The internal compressor switch is left in the on position. From either location I can turn on/off the compressor.

The only issue is the compressor may be powered on but not running because it's up to the pressure setting and from the switches you can't tell if the compressor is energized or not (no on or off position with 3-way switches). So simple solution, I added 2 extra low voltage wires that are connected to the contactor coil. They run to a 24 v led mounted next to each switch (2nd half of project, yet to be done).

Just because I could, I drilled 2 10mm holes in the top of the box for 2 230v leds, one red, one yellow. One will be connected to the line side of the contactor, the other to the load. When standing next to the unit I will be able to tell if the box has power and if the compressor is powered, even if the motor isn't going.

Almost done :) just have to connect the 230 in the box and run the thermostat wire.

compressor 20240602_140502.jpg


compressor control 20240602_140450.jpg
 
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kubota M4050

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I worked for IR in another life. Make sure you have a true 230v. If you only have 215 your compressor will not run right and over time will burn up the motor, also make sure you have the right size braker.
 
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ctfjr

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I worked for IR in another life. Make sure you have a true 230v. If you only have 215 your compressor will not run right and over time will burn up the motor, also make sure you have the right size braker.
Thanks!
Yes he had it running for years with no issues and I've tested it several times. All good so far :)
 

ctfjr

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OK, now I need some help :(

I finished wiring the 'box' except for the 2 monitoring lights that aren't in yet. I jump the low voltage leads on the top to simulate an 'on' call. The contactor snaps right in. No compressor :(

So i pull out my meter. 231 volts on the line side of the contactor, 0 on the load side. So I say to myself, self one pole must be bad and its a 3 pole relay so just swap to the 3rd pole. To see which one is bad I test for voltage between each load leg and ground. 0 on both.

I'm no genius but it seems impossible to me that a brand new contactor isn't making contact on either pole. . .

Other than changing it, anyone have any suggestions. It's a small pia to pull it out - it is mounted on a chassis base that I can remove.
 

GreensvilleJay

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Assuming you're talking about the 3 pole contactor in the picture of post #1......

The black square in the middle of it.. is it the 'manual push to test' ?
Maybe post the make/model info or a better picture of it. At 300% zoom , I can't read the wiring diagram on it. Really, they are simple.. put 24 AC ( IF AC model ) ,clunk, 3 poles connect...
One of the 'be nice to be there' problems.....


Also, for safety's sake, you need to have a disconnect to kill power at the compressor.
240 generally doesn't kill you...it just makes you jump back REAL FAST and THEN you slice yourself open. If you're lucky you can get to the bandaids.....
 

ctfjr

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Thanks GreensvilleJay - I agree couldn't be a simpler device. . .
here is a shot I took this afternoon as I couldn't read the small print on the contactor label
contactor 20240603_101152.jpg


Just L1 / L2 and T1 / T2 are used. The company I used to work for (as of last Friday) sells hvac accessories. They have a 40amp 2 pole in stock. Going to pick it up tomorrow.

It's just so frustrating as I can't believe a new contactor is bad on all 3 poles. It sure snaps closed nicely when actuated.

Yes, the compressor is within 3 feet of the breaker box (closer than I would have put it).
 

DustyRusty

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Depending on the horsepower of the compressor, the code might require a manual disconnect between the panel and the compressor. I ran into this when I hooked up my 5 HP Quincy compressor. Technically it is supposed to have a manual disconnect installed between the breaker panel and the compressor. It is also supposed to be in EMT to be code-compliant for a garage.
 

GreensvilleJay

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wow, Google couldn't find it !!! Even has a QR square on it , sigh....
I'm baffled....
Would like to know what you find as to WHY it don't work !!!!
 

InTheWoods

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...I can't believe a new contactor is bad on all 3 poles. It sure snaps closed nicely when actuated...
Hmm. Any chance you pushed the wire in too far, and clamped the terminal screws down on the insulation instead of the copper conductor?

Or maybe this contactor is a counterfeit POS off Amazon?
 
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North Idaho Wolfman

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OK, now I need some help :(

I finished wiring the 'box' except for the 2 monitoring lights that aren't in yet. I jump the low voltage leads on the top to simulate an 'on' call. The contactor snaps right in. No compressor :(

So i pull out my meter. 231 volts on the line side of the contactor, 0 on the load side. So I say to myself, self one pole must be bad and its a 3 pole relay so just swap to the 3rd pole. To see which one is bad I test for voltage between each load leg and ground. 0 on both.

I'm no genius but it seems impossible to me that a brand new contactor isn't making contact on either pole. . .

Other than changing it, anyone have any suggestions. It's a small pia to pull it out - it is mounted on a chassis base that I can remove.
So you can measure 120 Volt from each pole to ground on the input?
Have you measured the outputs of the contactor without anything connected to it?
 

ctfjr

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I have checked the input - 230 across L1/L2, 115 across each line to ground. Nothing on the load terminals (with or without the compressor connected).

I won't know exactly what's up with it until I pull it later today. I picked up a new contactor this am.
 

ctfjr

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Hmm. Any chance you pushed the wire in too far, and clamped the terminal screws down on the insulation instead of the copper conductor?

Or maybe this contactor is a counterfeit POS off Amazon?
Anything is possible of course but I am pretty careful on stripping / inserting wires. I'll take it apart after I remove it.
 

chim

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ctfjr

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Found the problem!!!

I tried one last thing before removing the contactor. I removed the top cover to expose the moveable contacts. When energized the magnetic coil is supposed to pull this armature attached plastic piece with the 3 contacts down.

Maybe not so much. With the cover off I energize the contactor. You can plainly hear the clunk as the armature is pulled down. This plastic piece with the contacts didn't move. It's supposed to be attached to the armature and move down with it.

broken contactor 20240605_151124.jpg


You can see the small plastic tab that is broken off. I didn't disassemble anything further but it obviously must lock the contacts piece to the armature. Was actually tempted to super glue it but I haven't reached that Neanderthal stage, yet.

Replacement contactor is mounted, just have to wire everything back up.
 

GreensvilleJay

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NICE, at least now we know WHY it wouldn't work!!!
Forget super glue..under stress it'll fail...Mr. Murphy can tell you when too !
 

ctfjr

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NICE, at least now we know WHY it wouldn't work!!!
Forget super glue..under stress it'll fail...Mr. Murphy can tell you when too !
Let there be air:
compressor 1st run 20240605_185816.jpg


limit must be set for 150psi, more than I need.

and at the drill press outlet (plastic box is where the low voltage switch / light will go - tomorrow)
air at drill press 1st 20240605_185911.jpg


regulator set to 100psi
 

ctfjr

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and the epilog. . .

After the contactor repair I installed the control switch in the garage and mounted a 75' hose reel. As always, some drama.
garage air control_20240611_182426.jpg


Everything was going fine until I started mounting the reel on the bracket that supports it. There are 2 bushings that serve as bearings when you swing the reel left to right. Of course I dropped one. I spent over an hour looking for it before I found it. It had landed in my work boot that was under the wooden shelving. . .

In any case everything works as it should.
 
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