Ingersoll Rand air compressor motor throws breaker

d9gdon

Member
My Ingersoll Rand air compressor motor has suddenly started throwing the breaker when it comes on. It doesn't happen every time. I am guessing that it is a capacitor?

This compressor is about 8 years old but it doesn't get used a whole lot. I would guess that it has about 300 hours of use during its life. When it was new, the motor went out in the first 10 or 15 hours of use and it was under warranty so they sent me a new one with no questions asked.

Here is the one I'm talking about.

https://www.external_link.com/tsc/product/ingersoll-rand-5-hp-single-stage-twin-cylinder-pro-air-compressor-60-gal-3301332?cm_mmc=feed-_-GoogleShopping-_-Product-_-3301332&gclid=CjwKCAjwp7baBRBIEiwAPtjwxDi_Es2jBm8wovnw2QG3Qgn1d_TCYmQnRAhT0eIfctj4oSg1rNL1RRoCb1QQAvD_BwE

How can I test the capacitors, or am I barking up the wrong tree? The motor is a 5 hp Emerson made in mexico, 56 frame, 3450 rpm, 230v. The bearings are good in it.

Looks like a replacement motor is about $400 or so. I'm not crazy about spending that.
 
If it runs/performs as always once it starts, I would first suspect the breaker.

It wouldn't hurt to (be safe while doing this) make sure the screw that fastens the wire to the breaker is still TIGHT.

Also, how about the "unloader", does it "unload" each and every time it shuts off, even before the failed start when it trips the breaker?
 
Since it has been working alright my guess is the breaker has gotten soft. Try changing the breaker first and see if that solves the problem. If that doesn't do it the compressor may be too far from the breaker box or the wire inadequate. I had to move my Ingersoll Rand T30 compressor about 30' closer to the breaker box before it worked well. Before I moved it the motor really had trouble starting when the temperature was well below freezing.
 
Does that model have an unloader valve, a 1/4" line going to the pressure switch?

If so, be sure it is working. When the pressure switch trips off, a lever pushes the pin in the unloader valve which relieves the pressure on the pistons for easy starting.

Before checking the caps, short across them with a jumper wire or screw driver to be sure they are discharged. If there is a pop, it just tested good!

To check the caps, give them a visual inspection. Usually a bad cap will have burned terminals, or a swollen case.

You can take them out of circuit and check them with an ohm meter. Set the meter to a high setting, connect the meter across the cap. The reading should jump to a low number, then bleed off to infinity. Reverse the leads, it should repeat the reading.

There is also a set of contacts under the end bell of the motor that connect the start cap to the start windings when the motor is coming up to speed. If the contacts are burned or not making connection for some reason, the motor will not start.
 
Well this is a strange post. I have the exact same unit also about 7 years old. Mine tripped the breaker when it tried starting last Friday. I replace the black capacitor first no change so then I replace the shiny metal one. I understand one is the start capacitor and one the run. Mine is still the same way tonight. Plan on pulling the motor tomorrow and taking it to shop. Both capacitors were less than 25 bucks total but the place I got them from said one was Odd. They had to order it. Nothing on the unit to confirm which is the run vrs start. My left side has two red wires right side has black and white.
 
I had mine completely rewound/rebuilt. Cost me less than $300.00. 220 volt, 5 HP single phase motor. Sounds
like a breaker to me.
 
Has it been humid in your area lately? I had something similar happen a few years ago and I'm pretty sure it was condensation in the
motor. If you run it long enough to get it good and warm will it still trip the breaker? I would try a different breaker before doing
anything to the motor.
 
We had a compressor with the same motor and the same problem it was the start switch inside the motor. tried to
buy another switch and was told none were to be had. Good luck Neil
 
Sorry about the late response guys, I forgot that I posted this question and then I was out of town last night. For some reason, I can't see my original question in the post.

Actually the electrical circuit breaker is not kicking out...the motor breaker switch is kicking out...the red one on the motor itself. The compressor is only about 10' from the electrical panel.

It has the 1/4" line going to the unloader, but when it starts and pumps up, I think I heard it unload and shut off normally. It is just acting like it's not getting enough electricity when it trys to restart and then it kicks the internal thermal overload breaker.

Not overly humid here, it's been at or above 100 degrees with no rain at all for a month or more.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top