Ingersol Rand Air Compressor Needs Repaired

[In The Doghouse]

I have an Ingersol Rand 80 gallon air compressor in an attached shed behind my backyard garage. It's been there for 10 - 15 years and is plumbed through the wall to several ports inside the garage. Occasionally I'm using a sandblaster or some air tools but for the most part I'm pumping it up about once a week so I have air on demand for inflating tires or using the air nozzles. In the recent past, when turning it on to pump up, it seemed to start slowly but did pump up. This slow start continued until now the motor will not start the pump. It'll strain until it kicks off the reset, but won't turn the pump.

Today I removed the guard and the belt and found I can manually turn the pump without too much effort. The motor turns freely with the belt removed. With the belt re-installed I can manually spin the pump pulley and power the motor and it'll continue to run. But won't start the pump without my assistance, it doesn't have enough grunt. The oil level in the pump head is to the proper level.

So, is it the motor at fault here? Does it need replaced?

What do the good Garage Journal folks think?

 

[TurnipTruck]

Take those two valve cover-looking sheet metal covers off of the motor and replace the start capacitors. Match the numbers written on them.

 

[In The Doghouse]

Here's what's under the two "valve covers". Do I replace one or both? Where is a good source for start capacitors? A typical electrical supply store?

Edit: I find start capacitors at Amazon and other sources. The Amazon is < $14 before sales tax. But Ktool has one for sub $5 with free shipping. This is, based on description, smaller diameter than I now have but it's captive in the cover. The third link below is an Amazon search for 250v Start Capacitor providing lots of options.

Amazon

Ktool.com

Amazon search

 

[marinusdees]

Here's what's under the two "valve covers". Do I replace one or both? Where is a good source for start capacitors? A typical electrical supply store?

Edit: I find start capacitors at Amazon and other sources. The Amazon is < $14 before sales tax. But Ktool has one for sub $5 with free shipping. This is, based on description, smaller diameter than I now have but it's captive in the cover. The third link below is an Amazon search for 250v Start Capacitor providing lots of options.

Amazon

Ktool.com

Amazon search

Match the mfd. spec range. 250 working volts (or more is OK). The other numbers are superfluous. ebay is another source. It will be nice if the physical dimensions allow placing them in the same position, but they'll work anyway. Replace both, or find someone (think electric motor repair shop) with a capacitor checker and check them.

 

[marinusdees]

Match the mfd. spec range. 250 working volts (or more is OK). The other numbers are superfluous. ebay is another source. It will be nice if the physical dimensions allow placing them in the same position, but they'll work anyway. Replace both, or find someone (think electric motor repair shop) with a capacitor checker and check them.

www.surpluscenter.com is another source.

 

[In The Doghouse]

Today I visited several local electrical supply businesses and they don't carry the starter capacitors. I called surpluscenter.com, as suggested above, but they don't carry the specific model that I need.
I found it on eBay and Amazon for $12 based on search for 233-280MFD 250VAC. I ordered from Amazon since they can deliver a few days earlier than the eBay retailer.

Thanks to TurnipTruck & marinusdees for your help.

 

[In The Doghouse]

This is puzzling. Today I received the new start capacitor from Amazon. It looks the same dimensionally as the old one and has the same specs of 233-280MFD 250VAC. I installed it and got the same results that the motor won't start the pump, but will if I spin the pump as I apply power. I reversed the connection leads, not thinking this would really make any difference, but why not. Still won't start the pump.

So I reinstalled the old start capacitor and the motor now starts up and runs like a champ. Wassup with that? At least the new capacitator wasn't but $12.

 

[Speed-Racer]

Almost sounds like you have a frayed wire somewhere. Let us know if you find your gremlin.

 

[The Cobbler]

I agree that it sounds like a bad connection

 

[In The Doghouse]

It continues to run just fine with the original start capacitor installed. I hope that whatever happened doesn't happen again, but you know it will at the most inopportune time.
At any rate I have a spare start capacitor in the drawer.
Thank you for all your help.

 

[redmondjp]

How tight is your belt? Believe it or not, a loose belt can cause some strange issues from having been on this site for a long time. You want about 1/2" of deflection in the belt midway between the pulleys.

You may also want to check your electrical connections in the entire circuit including the circuit breaker. You could have a high-resistance connection which is impeding the starting current (which can momentarily be 5-8 times the normal running current) and causing the motor not to start properly.

 

[jhelrey]

Take an air hose with blow nozzle, go to your motor, and spray it out really well. I had same issue, bought same parts, ended up just being dirty and contact wasn't being made due to dust/dirt.

 

[Mallen]

Be very very careful spinning up a motor with a pulley by hand. You can loose a finger like that. I slashed my fingers pretty bad on a motor that was off when I was checking if it turned freely. If it had been powered it would have taken them off. And dont wear gloves, they get caught and drag your hand in.


You said there are two capacitors on your motor. Did you assume both were the same size? They may not be. One should be a "Start capacitor" and the other a "run capacitor". The run capacitor is always in the circuit and provides an additional phase that the motor requires. Since the motor would run when you gave it a spin, the run cap must have been at least somewhat functional.

The start cap is usually (always?) switched into the circuit when the motor is at low speed or stopped. It provides extra torque during startup. It's switched out with a centrifugal switch when the motor comes up to speed. If that cap is gone, or the switch is stuck open, the motor won't spin up by itself.

Things to check are the switch, the wiring,the wiring connectors and the terminals on the capacitor. Also make sure that the caps are not different values if they values were significantly different, it might explain why it didn't work when you replaced them. Or if a wire or connector went bad. I'd the switch was stuck, it might have (perhaps temporarily) corrected itself when you messed with the motor.

 

[In The Doghouse]

Thank you for the advice. I agree that spinning a pump pulley to start the motor is a recipe for disaster. One could lose fingers if caught in the belt or the spokes of the pulley. I spun the pump pulley from the opposite side from the motor and made sure I stayed clear of where the belt feeds onto the pulley.
With that said, this motor & pump combo continues to function as it should. The new motor starter that I tried now sits on the shelf as the original motor starter is functioning. Maybe there was trouble with some switch contact that worked itself out.
I'm puzzled but thankful, nonetheless.

 

[Mallen]

If it's working, do t mess with it until it quits again.

 

[Citation]

Did you ever check the motor's centrifugal switch? It's a mechanism inside the motor housing that engages/diengages the starter capacitor. It's possible that the switch is making poor connection but something you did helped enough to keep it from stalling the motor.

 

[bsaint]

Silly single phase problems lol. Just kidding. Usually if the motor can't figure out which way it wants to turn its the start winding