This seems to be happening more and more lately, as I don't remember this being a problem when I first bought this SOB... It's a 120v Craftsman upright, 30-gallon, oil-free (I know, I know :rolleyes: ). It seems like everytime the damn thing needs to fire up, it trips the breaker? I have to toggle the breaker SEVERAL times in most instances to get it to start. I can hear the motor trying to turn over, but it just doesn't go. I'm no electrician, so where do I start here???

My father (had it fixed last week) had the same issue under warrenty they replaced the whole motor, it was drawing 37 amps at start up.

Unfortunately I'm well out of warranty...

Start with replacing the breaker. Do not increase the amp rating , just a fresh breaker.

Tried that, same issue. I did actually try a 20-amp breaker (manual says 15-amp is sufficient) for a while with the same results. This is on a dedicated circuit, nothing else plugged in, not even another outlet on this circuit. Just the compressor :(

Sounds like your piston is scuffing and the motor is pulling high amps to start. Make sure the unloader is working correctly. Got an amp probe?

its not an oilless, but I had to adjust (lower) the pressure switch to keep the breaker happy. no problems since. less pressure=less torque required=lower amp draw

edit: the unloader was working on mine, it would start and run for 10 seconds before tripping

you have pm....

your start up capacitors could be on there last legs. They can be replaced.

Breakers do wear out with time, they either stop tripping or start tripping all the time. but if you replace with a 20amp and its still doing it I'd check the motor, and the pressure settings, its alot of work for the compressor to start under load.

Check with sears for a rebuild kit for the comppressor (they used to have them) My buddy had a similar problem and rebuilt his and it worked a whole lot mo' better. If it's not electrical, it may be the cylinder/piston/valves worn out. It should be cheaper to fix than a new one..but these days of "disposable everything" who knows? At least keep the tank if it's not repairable...more air capacity :D

My old Sears has an unloader built into it also, so when it reaches pressure and turns off it drains the cylinder head so when it kicks back on the motor is not starting under a load. If that's not working you could kick the breaker every time.

Go to Sears web site and look up your compressor model number. It should have a diagram of yours. I've ordered parts off the net and had them in about two days. My compressor is starting to do the same thing. It's on a new 20 amp circuit,12 ga wire, 5 ft. from the electric panel.

Know anyone that does a/c work? You could try a hard start kit. It's basicly a big capacitor that piggy backs the one on your motors capacitor with a relay to shut it off. It gives it a hell of a boost to help start, will work for a while sometimes.

You got an extension cord connected to it? I had an issue with mine that when I used an extension cord it would trip the breaker but when plugged directly into the wall it was fine.

I Have the same problem with my crapsman 30 gal upright...

Trips breaker every time it starts up.

15 AMP as well.

I agree with the capasitors being dead or dying on this. They are probally the cheapest to replace first. Also with the amp probe it will tell you what the inrush current is at and allow you to decide what the problem is as well.

Also check the pressure relief valve on start up but I think it is more likely to be the motor.

Also if you have a Megger device you can test the motor windings to see how it is doing.

You got an extension cord connected to it? I had an issue with mine that when I used an extension cord it would trip the breaker but when plugged directly into the wall it was fine.

x2, could well be more complicated but that was the problem that I had with mine and I don't remember the gauge but it wasn't a tiny cord. Just a little too long, I guess.

x2, could well be more complicated but that was the problem that I had with mine and I don't remember the gauge but it wasn't a tiny cord. Just a little too long, I guess.

Voltage drop across a conductor will definitely do it. As a matter of fact I'm having a problem with that on my HVAC right now. Just occassionally, it will pop a breaker if it runs a LOT. The conductor is right on the edge as far as length and gauge goes, ran the last compressor fine but this one is just a bit too much.

I've run into an issue in the past with ONE ground fault protection outlet that is in my garage. For some reason, it didn't like my compressor even though I wasn't plugged into it. I changed it to a fresh GFP and the compressor has been happy since :D

JP

My brother and I both have the same compressors you have, and they both trip 15 amp breakers. I ran a new 30 amp circuit with 10 gauge wire, 30 amp plug and receptacle. Those are "5 HP" motors, and they have huge capacitors already. They just plain draw a large inrush current at startup. When it was on the 15 amp circuit, I noticed if I was using mine regularly through the day, it did not trip the CB except for the first start of the day.

No extension cords, just the factory line plugged directly into the dedicated outlet.

Postal - Mine seems to be the same way? After a couple of successive runs, it will *generally* kick over and run without tripping the breaker. But the first one of the day ALWAYS trips it, and if it sits for a couple hours between runs, it'll trip the breaker. :mad3:

tobyw, I would put in the 30 amp circuit. I don't think there is anything wrong with the compressor. Mine's been that way for several years - I've had it at least six. I don't use it a whole lot, but it shows no signs of death coming on.....

my dad and I have pulled a leg off a 220 circut and used it as 110. never tripped that breaker. we had old house and old wiring and was the easiest and cheapest way around it. if you were smart you could take a 30 amp plug or 50 whatever your house runs, and use a fat 110 cord to that plug, and then there is your adapter to run you compressor.

my dad and I have pulled a leg off a 220 circut and used it as 110.

This is how most houses are wired. The "220" volt electrical service feeds the panel with two hot legs. A voltmeter would read about 240 volts across the two hot legs, and 120 volts from either hot leg to ground. The 120 volt circuits are simply wired from one hot leg and ground (neutral).

I know that, but you also have a dedicated 220 to your stove or to a dryer. plug into that and use it's breaker. there will be no more popping of breakers, and you will have plenty of amps for start up on you compressor, and plenty of amps to keep it running while the pressure in the tank gets higher. it is the same as how your house is wired, but splits off where you need it, not split off then ran throguh all the outlets and then to your compressor. the wires in the house not necessarily the things plugged into them is where the power is getting lost and creating problems at the air compressor. too small a gauge wire, to many outlets on one circuit. the microwave being used, the heater for your house running.
It is a hell of a lot easier to tap into the 220 in your garage then it is to add a breaker, run the wire and install outlets and shit. unless you don't mind conduit running everywhere.

I understand your point, but just remember that the breaker needs to be sized to protect the conductor (wire). That's it's purpose. If you just move a 14 or 12 gauge wire over to your 60 amp breaker for the stove, your wire is not properly protected. This is why I ran a new 10 gauge circuit to a 30 amp breaker.

I don't want to sound like Smokey Bear, but I want to keep unknowing people from creating a fire hazard. I guess that does sound like Smokey.:D

Does the motor sit there and buz for a second or does it just trip right away?

If it is a motor with a centrifugal clutch to switch the starting cap in and out, maybe the clutch is sticking in the run position. Have had mud dobbers cause this a few times over the years.