the motor will not turn on, it just hums

by crbaker
(ohio)

It just hums, the motor does not turn over. it was left on, and I believe that the air tool that it was connected to was leaking air, causing it to run a lot in a 24 hour period,

_________________
First check. Shut it off, dump all the air out of the tank to zero PSI, close the drain and try to start.

Does it?

Please post a comment here.

Bill



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Dec 08, 2014
Air compressor Just hums
by: Anonymous

Hi, same thing happening here. The compressor works fine intermittenly. I shut it off at about 60-80psi before it auto shuts off since I don't need much pressure and I'm afraid to run it higher since its old. (I did tap the bottom with a hammer to see if it dented and it did not but I'm just paranoid. I let a friend borrow it for about a year and wasn't sure he properly drained it all the time.) Anyway, could this be causing the problem? When I try to turn it back on, it just hums and doesn't start. If I leave it for a long while, I hear a click and it seems to be good to go again. at what pressure will it auto shut off? How can I be sure its safe to operate at that pressure? and why does it start up fine once and then hum until left alone? The Unit is a craftsman oilless 4 gallon 3/4hp pancake compressor. Please help.

Dec 04, 2012
Slow on pumping air into tank
by: Joe Flores, Jr

I own a Farmhand from TSC 3/12 hp, 30 gal. The problem is when I first start it up it pumps good but when it nears on filling the tank the pump slows down to a very slow speed as if not getting enough power what could be causing this problem?
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The logical question is, is it getting enough power? You are not using an extension cord, I hope?

Assuming not, your motor is slowing as a result of an increasing load. That may be due to a run capacitor failing, the motor itself wearing out and needing rebuild, or it could be a mechanical issues with the check valve, or pump innards, particularly the valves.

Start by making sure that the intake filter is clean (remove it briefly to see if running the compressor without it solves the problem), and then checking the caps. See the page on this site about how to do that.

B.

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humms wont start

by byron wright
(illinois)

humms wont start trips unit breaker
________________
Byron, what is the make and model number please, and what is the pressure in the tank when the compressor motor is humming and then the breaker pops?

Thanks,

Bill

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will not build pressure

by albert
(dallas,tx 75232)

it go,s up to 30psi and it just on running
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Albert, see the troubleshooting section on the site map page, follow the link to the page about why compressors run and don't build pressure.

B.

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The compressor will not start?

by Clara
(UK)

The compressor worked several times and performed without issue. I used it 30 days ago, unplugged it with 8bar air in for several days, then released the 8 bar air, left the condensation drainage tap open. Now the compressor will not start. I checked the oil level and power, they are fine.
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Hi Clara... that you left air in the compressor for a few days would not cause your compressor-not-start problem.

The only down side to leaving air in the tank is that you are leaving condensate in there as well, and metal and water react with rust, as I expect you know.

You say the power is fine. Good. I expect your compressor is 240 Volt, so if you are messing with it, as you will need to to do the first check, extreme care is required.

What I would like to know is if the power is actually getting past the pressure switch and flowing on to the motor circuit. Some sort of a voltage detector (multi-meter) is necessary to probe the wire on the motor side of the switch to see if there is power.

With no air in the tank the pressure switch should have tripped to passing. This means that power should be flowing to the motor.

If it is not flowing past the switch, the switch is off, or the switch has failed.

If power is flowing past the switch, the next logical check would be the start capacitor, assuming your compressor motor has one.

Does this help at all? You might also check out the Troubleshooting section on the Site Map page for links to pages about why air compressors will not start.

Cheers,

Bill




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