Compressor motor not turning on

[supersaiyan93]

I have a 60 gallon vertical Campbell Hausfeld compressor that's about 12 years old. 3 HP 240V single phase motor.
I have used it for light duty work, always being very diligent to drain the compressor after each use, etc.

Any way, last night I went to use the compressor and the dang thing won't turn on. No buzzing, no tripping breakers, just no sign of life at all.

My troubleshooting so far:

I have 120V on each leg of the power cord.
I have 120V on each leg past the pressure switch on top (the tank currently has less than 10 psi in it).
I have 120V on each connector going into the motor itself.
Ground is good at the motor and the pressure switch.

My motor has a red reset button on the front, but it is not pushed out, and I can't push it in any more than it currently is.

I also disconnected the drive belt and turned the motor and the compressor by hand to make sure there was no mechanical binding.

Any ideas for further troubleshooting? I'm not much of a pixy wrangler, so any help would be very much appreciated.

I'm about to pull the front face to check continuity of the reset button on the motor to make sure it's still good. But other than that, I'm not sure what to check.

 

[dogdog]

Continunity test?

It's an AC motor right?
If it has a capacitor, unhook it first... then do a continuity test (ohm test) this would test the run winding at least give you a general picture if anything is broken... like a reset switch or a thermo protective fuse embedded inside the winding sometimes.

Then test the start winding if you have it... from the two point where you unhook the capacitor... one end should test continuity to one end of the lead, and the other would test out good on the other.

then test out the capacitor and see if it is within range. +/- 10%

 

[dogdog]

That assume that you have tested out everything external control and you have 240V on the leads to the motor when it is switched on....

 

[dogdog]

I have a 60 gallon vertical Campbell Hausfeld compressor that's about 12 years old. 3 HP 240V single phase motor.
I have used it for light duty work, always being very diligent to drain the compressor after each use, etc.

Any way, last night I went to use the compressor and the dang thing won't turn on. No buzzing, no tripping breakers, just no sign of life at all.

My troubleshooting so far:

I have 120V on each leg of the power cord.
I have 120V on each leg past the pressure switch on top (the tank currently has less than 10 psi in it).
I have 120V on each connector going into the motor itself.
Ground is good at the motor and the pressure switch.

My motor has a red reset button on the front, but it is not pushed out, and I can't push it in any more than it currently is.

I also disconnected the drive belt and turned the motor and the compressor by hand to make sure there was no mechanical binding.

Any ideas for further troubleshooting? I'm not much of a pixy wrangler, so any help would be very much appreciated.

I'm about to pull the front face to check continuity of the reset button on the motor to make sure it's still good. But other than that, I'm not sure what to check.

You'll also needed to verify there is 240V across the two Hot Leads... If the 120V of each hot legs that you verify is from the same leg at the panel, then you have only 120V open circuit. But shouldn't be an issue since you have it for 12 years, doesn't hurt to verify, it's part of the troubleshooting.

 

[wyliesdiesels]

You'll also needed to verify there is 240V across the two Hot Leads... If the 120V of each hot legs that you verify is from the same leg at the panel, then you have only 120V open circuit. But shouldn't be an issue since you have it for 12 years, doesn't hurt to verify, it's part of the troubleshooting.

was gonna mention this.

Troubleshooting should always include line to line readings in addition to line to ground...

 

[alfredeneuman]

If it has a capacitor, short circuit the terminals before you disconnect it.
Capacitors can hold a charge long after they are disconnected from the power source.

 

[supersaiyan93]

Continunity test?

It's an AC motor right?
If it has a capacitor, unhook it first... then do a continuity test (ohm test) this would test the run winding at least give you a general picture if anything is broken... like a reset switch or a thermo protective fuse embedded inside the winding sometimes.

Then test the start winding if you have it... from the two point where you unhook the capacitor... one end should test continuity to one end of the lead, and the other would test out good on the other.

then test out the capacitor and see if it is within range. +/- 10%

Excellent. Okay, continuity looks good across the windings. Continuity between the start capacitor and main motor leads looks good testing as indicated, but only with the start capacitor switch pressed in (more on that later.)

You'll also needed to verify there is 240V across the two Hot Leads... If the 120V of each hot legs that you verify is from the same leg at the panel, then you have only 120V open circuit. But shouldn't be an issue since you have it for 12 years, doesn't hurt to verify, it's part of the troubleshooting.

Yep, 240V total across the leads.

If it has a capacitor, short circuit the terminals before you disconnect it.
Capacitors can hold a charge long after they are disconnected from the power source.

Indeed. Years of working in IT has put a healthy fear of capacitors in me. We were trained to never open power supplies or CRT monitors. I always treat capacitors as if they are loaded guns strapped to a rattle snake.

At any rate, I believe I found my problem.

The run capacitor only engages when the little centrifugal clutch assembly lets the contact pictured below engage the switch. Once the motor gets up to speed, weights on the "clutch" spin out and pull it away from the switch, disengaging the capacitor. When I took the motor apart, a small piece of plastic and a spring fell out.

Looks like the tiny arm that contacts the "clutch" broke, permanently disengaging the start capacitor. Also the small hinge on the contactor plate for this arm is broken, and I can't locate that piece of plastic, or I'd be tempted to glue it back.

I'm trying desperately to find the contact assembly on the front of the motor to no avail. I can't believe I might have to swap out a $200+ motor over literally .0005 cents of plastic.

 

[OccupantRJ]

Find a local motor rewind shop if possible and show them what parts you need. Barring that, there are electric motor parts companies on the web.

 

[dogdog]

good luck in finding that one, maybe calling the manufacture... I think most of them will help you out... at least the reputable ones... for a price. Or find a motor shop, but they have been dropping off the business directory for various reasons.

 

[supersaiyan93]

My google-fu is legendary given enough time. lol.

I found a part number on the switch "334665". I didn't find much for this except a few specialty vendors that wanted $100 or so, but I did learn that the correct part name is an "Emerson stationary switch".

Looking that name up showed me an ebay auction for the exact part I need for $20! The auction didn't have much detail in the item description, so being as specific as I was being would have got me nowhere to locate this.

Whew.

I should have it in a few days. Hopefully I'll have good news after that.

I also need to figure out a way to test this start capacitor while I'm at it. My old Craftsman DMM doesn't seem to have that ability.

Thanks everyone for their excellent advice. I'll update this thread to let you guys know how it goes!

 

[The Cobbler]

cool, sounds like GJ comes thru again !
wonder how much of this stuff gets trashed for a simple fix

 

[Bert_]

I also need to figure out a way to test this start capacitor while I'm at it. My old Craftsman DMM doesn't seem to have that ability.

Thanks everyone for their excellent advice. I'll update this thread to let you guys know how it goes!

Use Ohm's on a high setting and put your probes across the capacitor, discharge it first. Reading should start out low and climb to infinity. Switch the probes around if you want to double check.

This won't tell you the exact value but it will tell you if it's open or shorted.

 

[jhelrey]

Super- In your second picture, there is a centrifugal switch. The brass tab moves up and down. Take a very small piece of sandpaper or emery cloth and slide it between the two contacts. Press down lightly on the arm and pull the sandpaper out. Do this about 3 times on for each side of the contact.

This solved my issue on my air compressor. Never started as easily as it did in a LONG time.

Just reread your post. Didn't realize you lost a few pieces. Oh well. This is here for future info. My compressor is the Kobalt 2 Stage 30 Gallon which there are numerous likewise brands.

 

[supersaiyan93]

Hmm....swapped out the contact switch, and no dice. Motor still does nothing. No noise, no sign of life at all. I might have broken the old switch in the process of pulling the endcap off the motor.

Did a little more checking with the multimeter. I get 240V across both legs on the input side, but I don't get 240V across both legs after the switch. I get 120 independently from ground to each terminal, but not 240V together. Is this normal?

In the picture attached, terminals 1 and 2 are line inputs and terminals 3 and 4 go to the motor.

I get 240V across the terminals marked 1 and 2 in the attached picture. With the switch in the ON position, I get 120V between Ground and terminal 3 and 120V between Ground and terminal 4. Jumping across terminals 3 and 4 shows 0 Volts.

 

[Bert_]

across terminals 3 and 4 shows 0 Volts.

Looks like 3 and 4 go straight to the motor. So there's your problem, one contact in the pressure switch is open (bad). Motor was probably fine all along.

The motor doesn't use a neutral so we have no interest in the voltage to ground, only line to line matters at the motor.

 

[mm08822]

Seems like the switch is bad. With the switch closed, Measure across 1 & 3 and then 2 & 4. One set will probably show 0 and the other 240 volts. The pair showing 240v is the bad side.

 

[supersaiyan93]

Looks like 3 and 4 go straight to the motor. So there's your problem, one contact in the pressure switch is open (bad). Motor was probably fine all along.

The motor doesn't use a neutral so we have no interest in the voltage to ground, only line to line matters at the motor.

Sounds plausible for sure. If nothing else, the cost of a $20 switch to learn a lesson in electric motor anatomy isn't too high a price to pay.

 

[supersaiyan93]

Seems like the switch is bad. With the switch closed, Measure across 1 & 3 and then 2 & 4. One set will probably show 0 and the other 240 volts. The pair showing 240v is the bad side.

So it does! Terminals 1 and 3 show 240. Terminals 2 and 4 show 0.

 

[dogdog]

huh u sure it is not 1 & 2 is the Line in (L1 and L2) , 3 and 4 is the output to the motor ?

There is that + and - thingy screw that should control your cut in pressure, maybe it was too loose.(vibrated loose), not 100% sure about your particular controls... some have adjustment for cut in and cut out, some have a set cut out and adjustable cut in.. cut out is the max pressure the compressor stops, cut in is the min pressure the compressor turns on.

... but either case if you have 240V in and 0V out... then there is the bad switch. Not really sure how you get 120V these things usually don't have neutral. Unless you are doing some wonky jumpers to the panel.

If it was me... .... not sure about you.

I would just unhook the belt from motor and the compressor, jump the motor directly and temporary with a 2 wire L1 and L2.... if the motor runs, then you can rule out that piece and concentrate on the switch. Use common sense safety of cause.

 

[TRWham]

He gets 120V to ground, just as he should. Ground is bonded to neutral in the main panel. When he sees 120V between 3 and ground and between 4 and ground, but 0 between 3 and 4, he is reading the same phase at both points 3 & 4 because it is conducting through the motor winding from the good switch side to the load side of the bad one.

 

[supersaiyan93]

Well, I had the wires loose to get the pressure switch off, so I jumped them across to the motor, flipped on the breaker, and the motor RUNS. In hindsight, I'm not sure why I didn't just do that in the first place. lol.

Bad switch confirmed. Found one on ebay. I'll have it in a few days again. haha.

 

[dogdog]

Your GoogleFOoOoO very strong.... ... I never had such luck finding parts like that........

before you rule out a bad switch...etc.... might want to take a pic of your setup... mark the screw setting... unhook incoming L1 L2 at that switch... and see if you can adjust that screw to get continuity that switch should be a DPST... so if you get continuity on both pole... your switch might be able to be salvaged.... I had to do that (messing with the cut in) when I adjust my cut in pressure on the smaller compressor to run my HVLP paint gun. Usually what I do is charge it up to max at cut out...then slowly release the pressure to a point I want to cut in... then adjust the screw till the compressor kicks in. wola just like that. Well in your case , adjust till the motor runs, once at cut out release pressure till the cut in psi and doing the same dance.

 

[Bert_]

I'm sure you could fiddle with it to get it working, for a while anyway. If you want a temporary fix I'd just smack it with a mallet. Chances are it will start working.

I wouldn't bet on any of that being a permanent fix though.

 

[weaser]

Hey guys, Im having the same issue as SuperSaiyan. Likely the same model C-H 60 gallon although mine is labelled a Husky. Its a 2007 model or so. Im on my second pressure switch. It was last changed in November 2016.

Went to turn it on and nada. No humming no nothing.

This unit doesnt get much use. Intermittent..like 5-6 times per year for a few days each time.

Checked and am geting 240v into the switch but nothing out to the motor with switch ON, and no pressure in the tank. The contacts look fine on both sides. I checked the wires and nothing burned or loose. Oil level normal. I have changed oil a few times over the years.

The contacts to the motor have continuity and the I pressed the switch on the motor (overheat protection) multiple times. 1ohm resistance across the motor.

Checked the microfarads on the run and start capacitors and both are in spec.

Could the pressure switch just have failed "interally"?

 

[weaser]

ok I scrutinized the contacts on both sides and I think I am seeing that one side is not closing. Its the side that is in between the motor and the switch so it impossible to see without sticking a camera in trying to angle for the correct shot.

I guess the spring lost tension? Can this be fixed or just need a new complete switch?

2 pics: the good contact and the other is the bad contact, both in "ON" mode.