My air compressor just died!

[evintho]

I/R 5hp w/80 gal tank. 175 hours on the motor. I was filling up a big air mattress and listening for it to cycle on as the tank purged down but it never did. It normally cycles at about 70psi. Checked the gauge and it was down to 20psi. Turned the switch off and on.......nothing. Could it be the pressure switch? I replaced the original PS about 7-8 years ago. Time for a new one? I can only hope it'll be that easy!
Thoughts or ideas please?

 

[Ole Slewfoot]

check your breaker.
And thermal reset on motor.

 

[Citation]

How big is the air mattress? In general I would recommend something like a shop can set to reverse to inflate something like that, Hugh volume, low pressure.

Regardless, I think a bit of methodical testing is needed here. First, with the circuit breaker off, does the pump and motor spin freely? Second with the breaker back on and the pressure low, does the pump get voltage (220-240v)? BTW, 70 psi seems like a very low cut in pressure. If you have a two stage compressor I would expect it to come on at over 130 psi and over 110 psi for a single stage. I'm throwing those out as minimums, not what I think the factory set it to.
Ok, if you are getting voltage at the motor check the thermal overload. BTW, do you have a magnetic starter or just pressure switch to motor (typical of lower cost compressors)?

 

[Michael_in_DE]

check your breaker.
And thermal reset on motor.

^This. Probably your house breaker.

 

[signcrafter]

Take the cover off the pressure switch and see if the contacts are touching. When the pressure gets low the spring overcomes the pressure and closes the contacts to send power to the motor. If contacts are closed then test for voltage at them. If that is good then move down the line looking at the motor and pump.

 

[Davefr]

1. Are you getting 220VAC to the input side of the pressure switch?
2. If so, are you getting 220VAC to the output side of the pressure switch with a low tank.

For#2 I'd turn off the breaker and use the ohms setting of your DMM to check for continuity between input and output side of your switch. (safer then probing for live 220VAC)

If the above checks out, you may have motor issues such as a thermal overload that needs reset or possibly a problem in the motors start circuit. (start cap, centrifical switch or windings). Maybe even a bad pump. Remove the belt if you hear motor hum but it doesn't start.

I thought I read that some 5 HP IR compressors had motor problems.

 

[evintho]

The breaker on the motor had popped. I reset it and the compressor ran for 30 seconds then popped again. I reset it again and nothing. Is that motor circuit breaker replaceable? That's it in the red area between the two capacitors. I'm thinking possibly a bad breaker or am I gonna have to spring for a new motor? Here it is when I got it in 2006.................

 

[Citation]

Check the running cap on the motor. What you describe is typical of a bad running cap.

 

[Davefr]

The breaker on the motor had popped. I reset it and the compressor ran for 30 seconds then popped again. I reset it again and nothing. Is that motor circuit breaker replaceable? That's it in the red area between the two capacitors. I'm thinking possibly a bad breaker or am I gonna have to spring for a new motor? Here it is when I got it in 2006.................

I'd put a clamp on amp meter to one of the 220V legs going to the motor. Compare the amps after startup but right before the breaker pops to the nameplate amps of the motor.

That should give you a clue if the problem is a bad thermal switch or a motor drawing too much current.

If the motor is drawing too much current then remove the belt and repeat the test. Also give the pump flywheel a few turns manually and see how it feels. If the motor is still drawing to much current with the belt removed, then test the motor's caps.

P.S. Have you checked the pressure relief/unloader valve and make sure the unit is not trying to start with the pump pressurized.

Good luck.

 

[BWS]

I'm with Citation ,post #9.

And if the new cap ain't exactly the same size(larger),NO worries. Get a pce of exhaust tubing,slit one side,open that chit up and make a new cover. This happens a lot with price point chiwan caps.

 

[Ben Buck]

Do you have this on it's own dedicated circuit !

 

[evintho]

UPDATE:
The run cap tested good but the start cap was leaking. Replaced the start cap and same issue. Here in town we have an awesome electric motor shop. Guys been in business for 50 years.
https://www.google.com/maps/uv?hl=e...ved=0ahUKEwjiztTN2K7bAhWJHnwKHWutChcQoioIbTAK

I pulled the motor and took it there. As I waited he disassembled the entire motor and tested everything. Turns out the windings had shorted in a couple of areas. One leg was barely pulling any amps and the other was pulling about 80a. Not good. It'd be cost prohibitive to rewind and repair the existing motor so I'm on the prowl for a new motor. Haven't researched yet but I know they're not cheap! Any recommendations for a new one?
230v
5 hp
FLA 22.5
56 series frame for air comp service
Service Factor 1.15 or higher
Insulation B or higher
Continuous duty
Shaft size 7/8"

 

[plinker]

Check here for a motor....https://www.surpluscenter.com/Electric-Motors/

 

[6PTsocket]

You said that the motor would not reset the second time. I had that.The motor thermal breaker had tripped and would not run. I heard it click when I pressed it but still N G. Then somebody gave me good advice. 220 motors have double pole thermal breakers. Sometimes only one contact resets, even though it clicks. I was told to "press until your finger turns blue" LOL. That did the trick. The breaker tripping is the result of your problem, not the cause. Follow the advice the others have posted to find the source of your problem. You should be able to run the motor for a couple of seconds if the thermal breaker is reset

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[evintho]

Well, I went ahead, bit the bullet and ordered this.......................

https://www.ebay.com/itm/5HP-3450-R...882542&hash=item3d3952618b:g:VHQAAOSwvbdZANoJ

It's actually a Leeson motor which I've heard good things about. The specs match my data plate perfectly and for $230 shipped.......I think I'm good! Should be here next Friday. I took advantage of the down time to change the oil in the pump, ordered a new air filter and installed a lifting ring in the top plate so I can use my engine hoist if I ever have to move it (last time it took 4 guys to lift it off the truck).

 

[evintho]

Up and running!!
Installed the new motor and it still wouldn't start! I bypassed the pressure switch and it fired right up. Bad pressure switch too! I guess the high amp load on that one leg pretty much fried the contacts in the switch. Replaced the PS and now all is well in the world! Tomorrow I can hook up my new sandblaster and blast the roadster frame. Feeling all tingly inside!

 

[469 runner]

The motors supplied with those compressors are not very good. Mine actually caught fire as the winding shorted out. I replaced the original with a Baldor 5 HP. Much higher quality.

 

[MacMcMacmac]

Up and running!!
Installed the new motor and it still wouldn't start! I bypassed the pressure switch and it fired right up. Bad pressure switch too! I guess the high amp load on that one leg pretty much fried the contacts in the switch. Replaced the PS and now all is well in the world! Tomorrow I can hook up my new sandblaster and blast the roadster frame. Feeling all tingly inside!

I'd be running a mag starter for a motor that size.

 

[evintho]

Yep, shorted windings were the issue! It actually lasted 12 years before it gave up the ghost. If I can get another 12 out of this unit, I'll be happy!

 

[FTG-05]

I'd be running a mag starter for a motor that size.

Same here.

 

[TTLLOGIC]

Baldor or Leeson you can't go wrong.


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