shuts off before filling

copressor shuts off before filling.

Bill says...

Note at what pressure the compressor shuts off. Drain the tank, start it again, and see if it shuts off at the same pressure point.

If you have a multi-meter, check to see if, when the motor shuts off and the tank pressure has not yet reached cut out pressure levels, if when the compressor shuts off, power is still flowing to the motor through the pressure switch.

It it is not, your likely culprit is the pressure switch.

If you want to add more info, please do it here as a comment so I can follow our discussion.



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harbor freight 40400 compressor

by Richard
(Shingle Springs, CA)

Harbor Freight 40400 air compressor rarely used.

The start capacitor blew (130mfd 220-250 volts).

I replaced it with a Packard PTMJ108 rated 108-130mfd 220-250 volts. The tech at HB said this would work.

I turned on the compressor and it started building pressure just fine when after a minute the cap started smoking.

I shut it off then waited a minute, turned it on and it runs but the smoke starts up again after a short time.

I continued this a few times until it finally wouldn't start; the cap was getting warm to hot.

I waited for it to cool off and it started then smoked. I opened the motor, it looked ok but I did not find a centrifugal switch.

So, how does the cap get removed from the circuit once it gets up to speed? Or is it supposed to be continually charged? Should I have gone up one size to 130-158mfd? What should I be looking for when taking a meter to the motor wires? There are a few; the two blue ones going to the cap, two white going to the reset switch and finally the hot, neutral and ground to the motor. Your thoughts?
Hi Richard....

Tell me a bit about where the compressor was when you were using it and what it was plugged into, please, as a comment here.



Comments for harbor freight 40400 compressor

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Mar 22, 2012
HF 40400 cap smokes
by: Richard

Thanks. The next model up would be rated at 130-158 which is higher rated than the one which is smoking and the original at 130. Would this work? Start cap vs run; the original one is rated higher than a typical run cap (as I have been reading). Why is this one always in the circuit? I'm wondering if the one I purchased is not designed to be 'charged' constantly. Your thoughts?
Happy to post this in the hope someone that knows can advise you on the rating of the capacitors, Richard. I don't have that info.

Mar 21, 2012
HF 40400 compressor cap smokes
by: Richard

The air cleaner looks brand new; clean and dry. I disconnected the outlet at the head and let her run. 50 seconds later the cap started smoking so I shut it off.

Either the motor is pulling too much from the cap, or the cap itself is wrong, or failing. This is all it can be.

Mar 18, 2012
HB40400 compressor cap smokes
by: Richard

I plugged the compressor directly to a 20amp outlet, turned it on and after about one minute the cap started to smoke. The pressure gauge showed about 85 pounds. Let me add that the capacitor has a white crusty film near the connectors, which was not there when new and only appeared after it started smoking.
Thank you. Now we are sure that it isn't the power supply. If the power supply to the cap is good, and the cap is overheating, that would suggest to me then that the motor is pulling too much power. Please double check that the intake filter is clean. Then, empty the tank, uncouple the line from the pump head to the tank so that there is no back pressure on the pump, and run the compressor for a few minutes this way. Any change?

Mar 17, 2012
harbor freight 40400 compressor
by: Richard

I hope I am not double posting.

The compressor is in the garage connected to a 10' 14ga extension cord which is plugged into a 20amp circuit. There is nothing else running on this circuit. The compressor has been in this location for a few years.
As noted in my last reply, please plug the compressor directly into the receptacle to see if this makes any difference, or move to a 12 gauge x 25' maximum length, extension cord.

Mar 16, 2012
HB40400 compressor cap smokes

It's located in the garage connected to a 10' 14ga extension cord which is plugged into a 20amp rated wall receptacle. This is where and how its been used since I first got it a few years ago. Nothing else on that circuit was running at the same time as the compressor.
Richard, can you move it to plug it directly into the receptacle without the extension cord, and see if that makes any difference?

As components age, they don't perform as well, and a marginal power supply some time ago may not be enough for today.

Let us know, K?


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