Air compressor issue

[shamrock12]

So last year I purchased a portable 20 gallons Campbell Hausfeld #VT640600DI (5.5 SCFM @ 90 PSI) air compressor. Today while doing some work, I noticed that it didn't kick back on and found out that a breaker has tripped. Thought that was odd since I never had that problem before using the same outlet, so I reset the breaker. It tripped again a few seconds later. So after some troubleshooting, I found out that the compressor can start and run when the tank is empty and open. It will continue to run until it reached the set pressure. But when the pressure get below the set point, the compressor struggled to start again and thus trip the breaker. I inspected the check valve and found it to be working properly. So I took out the capacitors and tested them using analog meter and they seems to be ok; however, I do not have a DMM with capacitor setting, so I am not ruling out the capacitors yet.

What I don't understand is if the check valve is working, that the compressor can only start and run successfully when the tank is empty It did seem to take a tad longer to get it going though. If there is a small amount of air in the tank, like 20 PSI, the compressor would struggle to turn and run, thus drawing too much current and trip the breaker.

Is there anything else common that I should inspect/troubleshoot? The compressor is only a year old and has been used about once a month. Today weather was nice and warm, so the oil viscosity is not an issue at this time.

 

[jhelrey]

Update your breaker to 15A

 

[larry_g]

When it kicks off do you hear the unloader blowing off? Run it up to kickoff and when settled crack the fitting at the pump and see if the pressure is gone and that no air is flowing back to the head from the tank. If that is ok then I believe your on the right track with the start circuit of the motor.


lg
no neat sig line

 

[shamrock12]

For safety reason, I reduced the tank pressure down to 40 PSI before cranking the fitting loose and nothing came out back to the head. I then attempted to plug the unit in and it struggled to run. There are two capacitors, one is rated 40uF, 450VAC and another is rated 240uF, 250VAC. I assume that the one with higher uF rating is for starting?

 

[Outlawmws]

If you have the same breaker in the panel, try swapping them, or try an outlet on a different circuit. I've had any number of breakers go bad and get sensitive.

 

[Motofixxer]

Yep try a different\new outlet then a breaker. Narrow down your variables. What else is on that circuit? Could be overloaded. Check to see if it's on a GFI, I have heard rumors of high loads not working properly on GFI's. My money is on the breaker or an overloaded circuit. Check the easy stuff first.

 

[shamrock12]

I can assure you that the outlet/breaker is not the problem. I have already tried a few different 15A/20A circuits with the same result. The issue is within the compressor itself.

 

[pro machine Engineering]

how many outlets do you have on that breaker. Are you running other things while the compressor is running that you wasnt running before

 

[Charles (in GA)]

If you tried to start it with the air pipe disconnected from the pump head, and the pump turns freely by hand, then the problem is in the motor. Could be bad (high resistance) contacts in the pressure switch, but doubtful.

There is a centrifugal switch in the motor that switches the start capacitor out of the circuit after the motor is running. Its possible its stuck, I've seen that happen, but this sounds like a bad capacitor.

Charles

 

[shamrock12]

Where would be a good place to buy a capacitor over the internet? Grainger doesn't seem to have one in correct canister dimension. Mine is about 1 3/4" in diameter and 3 3/8 in length.

 

[Coach James]

Where would be a good place to buy a capacitor over the internet? Grainger doesn't seem to have one in correct canister dimension. Mine is about 1 3/4" in diameter and 3 3/8 in length.

One place I would look for the capacitor is a place that sells appliance parts. When I had to replace the capacitor on my heat pump last summer, that's where it.

Coach

 

[shamrock12]

New capacitor came in today. Still the same problem. Guess the centrifugal switch or the winding is messed up

 

[shamrock12]

Just thought I'd give an update - after troubleshooting every little part of the compressor, I could not find exactly where the problem is coming from. The check valve is functional, the start capacitor is good, the centrifugal switch is functional, the motor and flywheel spins easily by hand, and so on. Even checked the voltage at the outlet and tried some 20A circuits to no avail. So I finally decided to bring it into the basement and plug into a 20A outlet right below the panel and the compressor worked immediately. To verify that it was not a fluke, I took a 100 feet heavy 12 gauge extension cord and plugged into the same outlet and the compressor struggled to start.

This is the equivalent of having an dedicated 20A outlet located 100 feet from the main. To me, I don't find this to be acceptable at all as it should have be able to run on an 15A circuit without a problem. Apparently there is an issue with the motor. It has never happened to be before, so I suspected something caused the motor to get weak, possibly the winding.

Very disappointing as this unit is only a year and an half old. It only get used on average of once or twice a month.

 

[rlitman]

When it kicks off do you hear the unloader blowing off?

^^^^^^^ This. Did you check this?