Air compressor motor keeps tripping breaker

[Kawiguy454]

+1 on the relief valve I bought my current cast iron 2 stage for $25 cause the motor was blowing the breaker and guy thought compressor was bad. I brought it home cleaned a booger out of the relief valve keeping it from opening and its been fine ever since that was over 10 years ago.

As was said before the motor should be spun up before the relief valve pushes open to fill the tank

Switch to 220-240 ...doubling the voltage halves the current ...so thinner wires longer runs etc.

 

[Oldmoparguy1]

I had the same problem, It failed under load. Was using a 14-3 drop cord. Replaced with a 12-3 drop cord and it works fine now. This was on a 15A 120 circuit. Your problem is, the motor is not getting the start current to kick it over. If it works at your neighbors, then your wiring is defective somewhere. Given your symptoms, it would likely be at the box. If it fails at the neighbors, your motor is bad. Either way, your not getting start current. Given the systems, I'm wondering if there is a fault of some kind in the start winding.

 

[Donald]

Try a clamp-on ammeter with a peak hold to catch the starting current. Is it a plain 20 amp breaker?

What does the plate on the motor say?

Rewire it for 220V. If its a dedicated circuit should not be a big change at the circuit breaker box. You do not need a neutral, just 220V and ground.

 

[spasm3]

I had this problem and i replaced the capacitors. Solved the issue, bought them on ebay for not a lot of money.

I may have an extra around. Although you probably have two on the motor.
Give us the capacitor specs, i might have one. also the physical size of the capacitors.

 

[TFB1]

Originally Posted By: e40


It still trips the breaker. I brought the motor back and they replaced the same part again, saying it was bad. Perhaps from re-trying to start it over and over? Still does the same thing after getting it home. This happens with the tank empty, or partially charged, doesn't matter.

If I take the belt off, the motor starts fine. Sometimes if I turn the motor / pump over by hand a few revolutions it will start. (With the belt / load attached)



With no air in tank there is no head pressure so it should start as easily as a free spinning motor... Either you have something causing a lack of torque on start up or the compressor is partially seized(which isn't likely as you said it would pump up and cut off once running)...

So you have a motor problem which is likely a bad capacitor(yes my bet even though tested OK)... The only real test of a start/run cap is under similar load, so test with the average cap meter is mostly useless... A cap with high ESR(equivalent series resistance) may well read the the rated 200mfd(just example) but when hit with a heavy load limits current... Caps with high ESR generally have at least partially dried out electrolyte...

If it were straining to restart(or tripping breaker) with 80-90lbs head pressure could be the pressure release, insufficient wire size or maybe weak capacitor... I had that problem with a 120v compressor I picked up used(had new motor), wound up rewiring motor for 240v and it been fine..

 

[Dan55]

I think its your breaker, SQ D makes a specific breaker for motor loads in Homeline series.

 

[threeputtpar]

Yep, roll it over to the neighbor's house and see if it displays the same behavior. Without doing that, there's too many variables to consider. This would rule out many of them.

 

[circuitsmith]

How old is the oil in it?
Had a similar problem with sluggish start-ups and changing the oil solved it.
Reduced static friction.

 

[e40]

Hmm. Original, unchanged oil and it's about 14 years old. I picked up a bottle of compressor oil and will change it out. As a BITOG'er I can't believe I've neglected that.

I disconnected the pipe going to the unload valve, so it was not in play at all. Still trips the breaker. The motor will spin up fine, multiple times, with the belt off.

I'll change the oil today, and also get out my clamp multimeter and run some tests as suggested above.

 

[LeeD]

I had a similar problem. Motor ran for about 6 seconds then tripped the breaker.
It's an oilless air compressor
Craftsman model 919.165200

In MY case, it turned out to be the Run Capacitor.
Replaced with GE Genteq Capacitor Round 40 uf 370 Volt VAC Z97F9614 97F9614 (found on eBay for $15.85

The unit runs well now and doesn't blow the breaker.

-Lee

 

[e40]

Brief update to this.

Decided to buy a new compressor from Blain's, a nice belt driven upright unit and they took a 10% coupon to boot.

I gave the suspect Porter Cable compressor to my friend and it's been fine at his house. (Same builder, same electrician, same main panel and breakers as well!) Just a year newer than mine, they just moved in.

The new upright seemed to be fine for a couple months, up until last weekend when helping a relative change brakes and using my air tools. Tripped the breaker a couple times, but not every time.

Could the main 200a principle breaker be defective? As stated earlier, the problem follows the compressor on every circuit I've tried. (Garage outlets 15A, garage heater 20A, clothes washer 20A)

 

[TFB1]

Uhhh maybe look at manual to see what amperage breaker they recommend??

Forget the main breaker, that isn't the problem...

The one I have won't restart on 120v circuit without tripping breaker(has replacement universal motor can be wired for 120v or 240v)... On 240v it's never tripped beaker...

 

[e40]

Manual says motor specs are 120V, 15A, 1 phase. Or 240, 7.5A, 1 phase. Doesn't specify breaker sIze other than saying they recommend a dedicated circuit, and as close as possible to the panel, which it is...

 

[turtlevette]

Someone asked about your voltage. A motor tends to draw more current at lower voltage.

Check the wire size. Check for hidden tapped loads on the circuit.

You might want to say f it and just put in a bigger breaker. I wouldn't have a problem doing it as long as its a dedicated circuit and it's always attended. Pop a 20 back in when you sell the house.