Old Compressor won't turn on

[brawls43]

Hey guys, looking for some help diagnosing what's wrong with my compressor. I picked it up at an auction a little over a year ago, and its been running strong since. Its roughly a 1950 Quincy 325 for the compressor, the tank is a little newer.

I had the tank inspected when I got it, got the green light and have been using on weekends since then. Very light use. Went out the other night to use it, and it wouldn't turn on.

I started checking the voltage coming into the contactor, and it had 120v at the entry to each leg, but not on the outputs.

So I check the pressure switch, and I think its working. It had continuity across the switch, so it should be working, right?

I used a clamp to hold the contactor, since the coil wasn't, and that gave me continuity across its leads then. So I tried applying voltage, and had 120v at each outlet, but the motor wouldn't start. Next I opened it up, and pulled the tape off the lugs for the voltage inputs.

It had 120v at each of the copper lugs shown, but the motor didn't budge. Doesn't sound like its even trying to start. Is the motor dead? Can it be fixed? Can I do anything to see which piece inside the electric motor died? It also seems like my magnetic contactor is dead too, but it doesn't seem like its the only issue? Anything else I should check or try? Thanks.

 

[Unmarked Bill]

I might have missed something in between the photos but it's a 220 motor getting 120?

 

[CoopVA]

Did you check if those Reset switches were tripped?

 

[Unmarked Bill]

If you're getting correct voltage to the motor and it's not turning, I'd start there.

Not sure if your motor is also from 1950ish, but I have single phase compressor motor from that era and the wires inside aren't numbered, not much a DIY'er can do at that point. I took it to a guy and he straightened it out.

 

[brawls43]

Its a 230v motor, has 120v on each leg, so there's 240v there for it. The reset switches aren't tripped. Neither is sticking out, and both fuses are intact.

 

[CoopVA]

Overload relay is probably gone... Could be a bad capacitor. Quincy is still in business, find a local dealer and see if they can fix it. Or you can get a new motor starter...

See this:

http://www.garagejournal.com/forum/showthread.php?t=156881

 

[Beta.Gamma]

Please check voltage between the two motor leads. I know you show 120V to ground for both of them, but verify that there is 240V between them.

 

[larry_g]

Please check voltage between the two motor leads. I know you show 120V to ground for both of them, but verify that there is 240V between them.

He saved me the typing, make sure you have your 240v as the 120 will come in one side and go out the other and make all look good.

lg
no neat sig line

 

[brawls43]

To measure between the two motor leads, I just put one on each, as opposed to the ground, right? Because it measure like 0.05 volts between the two hot leads, but still 118v from each lead to ground. I take it this is bad.

 

[monkeyspanners]

Does the contactor pull in when you turn the power on to it?

 

[brawls43]

No, the contactor isn't pulling in.

 

[monkeyspanners]

Its either not being asked to due to pressure switch or overloads et al or something is preventing it such as lost phase/neutral, burnt coil, mechanical failure etc from being able to activate.

 

[Beta.Gamma]

Please measure voltage across the two input leads for the contactor. Then measure voltage across the input and output of the contactor (input 1 and output 1, then input 2 and output 2). Leave the clamp holding your contactor closed.

 

[brawls43]

How would I tell if its not being told to by the pressure switch? Would the lost phase/neutral be caused by the contactor? Can you force the contactor shut to see if it'll work or if its the broken piece?

 

[justold]

reset the circuit breaker in the breaker panel serving the compressor.
Be sure to firmly push the handle to off before turning on , then check voltage across L1 and L2 to verify 240 volts

 

[brawls43]

Here's what I measured:
L1-ground: 118v
L2-ground: 118v
L3-ground: 118v (not sure why its jumpered between L2-L3)
L1-L2: 0.06v
L1-L3: 0.06v
L2-L3: 0.06v

L1-T1: 0.06v
L2-T3: 0.06v
L3-T3: 0.06v

 

[brawls43]

I'll open the box and check the voltage at the breaker next.

 

[metal4130]

How would I tell if its not being told to by the pressure switch? Would the lost phase/neutral be caused by the contactor? Can you force the contactor shut to see if it'll work or if its the broken piece?

You need to check the "control" part of your circuit. The on and off of the motor starter is controlled by the pressure switch. To do this, check the continuity between those two thin black wires that enter the panel.

If there is no continuity then the motor is not supposed to come on so maybe there is something wrong with the pressure switch.

 

[brawls43]

Thanks for the help guys, it looks like its the circuit breaker in the panel. I took the cover off the box, and I'm not getting 230v across the double breaker, but I do on all my other double breakers. I thought since I had 120v on each lead going into the contactor that I had both power leads, but it looks like its not. Good news then is the motor isn't dead! Thanks for all your help! Its frustrating when you think you clear something in the troubleshooting, but its not working.

 

[JW in MO]

First I would re-tape the connections up. You should have over 200 volts between L1 and L2. Those wires should come directly from your breaker. Take the cover off the breaker panel and check the breaker, one lead on each terminal, if it doesn't register over 200 volts there shut your breaker off, turn it back on and recheck. If it still doesn't register over 200 volts, the breaker is bad. Checking one leg to ground only confuses the process, you need to check phase to phase.
Is your pressure switch wired up?
Also inside the cover of the motor starter should be a wiring diagram, could you get a clear picture of it? Another picture showing the wires clearly in the top of the motor starter, (wires from the conduit to L1, L2 and the jumper).

 

[JW in MO]

OOPS, we were typing at the same time, you hit enter before I did. Glad you found it, one of the cheaper fixes.

 

[Beta.Gamma]

Yes, sounds like half of the breaker failed. I've seen this before, not sure why/how this happens? A new breaker should have you back in business.

 

[scw1991]

First thing I'd do is remove the v-belt so motor shaft is able to spin freely. Then see if the motor starts by bypassing the mag starter completely.