Air compressor problem-questions

[hitekcountry]

One of my air compressors has been acting up for some time now and I'm debating wither I should try to fix it or just get a new one. When I turn it on nothing moves and you can hear it struggling to start and if I don't turn it off right away it will trip the breaker. The way I get it to work is to rotate the flywheel on the compressor (which turns to motor too) and then switch it on and most times it will then start. Before, that would work every time, but now I have to do that a number of times before it starts, so it's getting worse.

The compressor oil level is fine. I'm assuming the problem is the motor.

My questions are:

Is it worth fixing?
Cost to repair motor?
Cost of new motor?

 

[Egon]

If you use an air compressor it should be worth fixing the one you have.

Take the motor to a proper shop and have them check it. It might need new capacitor or switches cleaned.

 

[dave1949]

There is a decmpression valve that should open autimatically when the compressor shuts off after a cycle. This bleeds air pressure off the pistons so the motor can start on the next cycle. You shuld find a small dia. tube that leads from the cylinder head area to this valve. If that the problem, just take apart and clean out the valve.

That's where the little pssst noise comes from when the compressor shuts off after reaching the set PSI.

 

[firedog]

I would tend to agree with Dave on the unloader valve. However, it could also be the start capacitor or start circuit on the motor. (some motors have a start capacitor and some have a start circuit with a centrifugal switch located inside the motor housing.)

 

[dave1949]

However, it could also be the start capacitor or start circuit on the motor. (some motors have a start capacitor and some have a start circuit with a centrifugal switch located inside the motor housing.)

Yes, after thinking about it, if it were the unloader valve, he might not be able to turn it by hand.
Dave.

 

[radioman]

just to share my experience- a couple weeks ago, my father's harbor freight Air compressor also did the same thing except trip the internal reset switch. We took the thing apart from pump to motor windings to capcitor. I ended up removing the reset switch from motor and wire it directly together and finally it started working right !! perhaps you could test yours with a jumper on the motor reset switch and see if it solves your problem. if not then work backwards from there to motor or on/off switches.

 

[tallyho8]

There's a 50-50 chance it's just the $5 start capacitor. You can check it with an ohm meter.

 

[hitekcountry]

There's a 50-50 chance it's just the $5 start capacitor. You can check it with an ohm meter.

So if I get anything other than 0 ohms, than that's the problem.

 

[dave1949]

So if I get anything other than 0 ohms, than that's the problem.

As I remember, it should start out low and climb as the ohm meter battery charges it.
Dave.

 

[kenmac]

If I'am not mistaken .. That's a dual capacitor motor.. Looking at 2 humps on the motor

 

[tallyho8]

I use an analog ohm meter to check capacitors. Touch the 2 leads to the 2 terminals and the needle will jump very high and then settle back down if the capacitor is good. If the needle doesn't move, or shows continuous continuity between the 2 terminals or one terminal and the case, the capacitor is bad.

PS: You must disconnect the leads from the capacitor before testing.

 

[RobertN]

I had a similar one. Bad capacitor. $5-10 for a new one. Try the reset switch first though.

 

[hitekcountry]

So if I get anything other than 0 ohms, than that's the problem.

I stated that wrong. I should have said there should be no conductivity through the capacitor and the resistance measurement should measure the same as an open.

And yes that motor has two capacitors.

Ok so I went out this morning and checked the caps and they checked out ok, so what's up with that? So I put the caps back, and in doing so I noticed that the connections on one of the caps were very loose, on the first cap the connectors snapped into place and were locked on. The second cap the connectors slid on easily but easily slid around, they didn't look to be making solid contact. So I crimped them until I could no longer slide them by hand.

Now the thing turns on every time I turn on the switch just like it's suppose to. That may very well be all it was.

I know in the past I more than likely would have just bought a new one and tossed the old one. But now that I'm retired, I have plenty of time, and if I can use my time to save money, great.

Thanks Guys!!!!!

 

[radioman]

awesome - you got it fixed. !

 

[Egon]

Good show.