Another air compressor circuit breaker thread

[Velocity-Duck]

I have a Craftsman 3.5HP, 15 gallon air compressor. Model # 919.152911

Whenever it starts up, it trips the breaker. Reset the breaker and it runs fine... Until it has to start again.

Power cord is good, no extension cord in use. Outlet is about 5' from the breaker.

I replaced the check valve and it still does this.

What next? Start capacitor?

 

[Roberts210]

Craftsman power tools are notoriously over-rated as to HP. That said, what does the motor's info tag say about amperage, and what amperage is the breaker?

 

[Velocity-Duck]

Craftsman power tools are notoriously over-rated as to HP. That said, what does the motor's info tag say about amperage, and what amperage is the breaker?

Not sure about the label on the motor. But for about 15 years it was connected to a 15a breaker and never tripped it. For the past three it's been on a 20a breaker and until about a year ago, never tripped the breaker.

 

[The Cobbler]

I had a compressor that didn't like to start (blow breaker)when tank had pressure. caps were good, everything checked out fine. minimal voltage drop etc. I added a cold start unloader valve, also called auxiliary unloader to the head line, solved my problem. adding more volume to the head line would have achieved same results in my case.

 

[jakemac]

Two thoughts :
1) What gauge wire runs from the box to the outlet ? 14ga may be too thin.
2) the trip mechanism on breakers can sometimes become "tired" with age or humidity. Have you tried a new 20a breaker to see if it solves the issue ?

 

[ItsNemo]

What's the full wiring path (panel, breaker, wire, plug, etc)? This is an oil-less compressor I take it?

It could be just worn out completely, pump is starting to seize up and the greater current is tripping the breaker.

 

[sberry]

The parts in them get worn a little, they were right on the edge when new . The wire to the panel is so short it delivers the current in a hurry. Add 50 ft of 14 cord to it. For testing 25 or 50 ft of 16 and see if it trips.

 

[sberry]

It's not tripping cause it isn't getting enough power. It's getting too much too fast. Doesn't need a bigger shorter wire but a smaller longer one. These comps come with a 14 cord, if it would be simple to fix them would change the cord to 12 but it makes the problem worse.

 

[bsaint]

Its most likely not unloaded when it starts. Check it pisses out air for a few seconds when it shuts off or the cold start valve is working.