My compressor won't start. It just hums.

by Tim
(Warrenton Oregon 97146)

If I disconnect the air line and spin the motor shaft it will start.I could run all day that way. I hook up the air line and it builds up presser then it shuts off. Than when I let the air out to make it kick on it just hums and i hear a relay kick of and than back on. All the windings in the motor still look brand new.


The model of the compresser is TD-5050
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Hi there Tim.

Please empty the tank. Then, start the compressor. Does it start easily?

If it does, and I think it will, monitor the pressure switch when the tank pressure gets near the cut out pressure setting. On that switch (or part of it) is the unloader valve.

Makes sure that the unloader valve is working when the compressor cuts out.

If you are not sure what the unloader valve does, see that page in the section unloader valve on the site map page.

Please comment here to tell me what you found.

Cheers,

Bill

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Sep 17, 2012
I do believe it's electrical
by: Ronald Norris

I think maybe that it's what is called a "brown out" It has to do with the outlet that you have it plugged into, switch to a different outlet and check it out.

If you have circuit breakers check the size of each, you most likely will need one that has 15 amps on it try to find the outlet(s) that this is connected to. Once it starts it will run okay.

I had the same problem and told an electrician friend of mine about it. That's what he told me to do, after tracking down which breaker went to where and found out the one with the 15 amp marked on it I plugged it into this one and lo-and-behold no more problems. But Bill knows A LOT more about this stuff then me so check his solution out first. Hope this helps.
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The neat thing about this site, Ron, is that anyone can help. I know a lot, but a lot of folks know a lot more than me about compressors.

Thanks for the help.

B.

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breaker on compressor jumps on restart

by Andre Martin
(Hudson, Quebec)

When I turn the switch on, the compressor tries to start and then the breaker on the compressor jumps.

I have to reset the breaker many times and sometimes it will start turning and building pressure. when it does starts, using an air tool, the pressure gauge goes down (normal) but the compressor will not rebuilt pressure, the breaker switch jumps again.

Also, this compressor is extremely noisy. I have also notice a small crack on the casing of the capacitor as well.This is a Kawasaki 5 gallon oil-less pump model 691531.
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Andre, do this test please, and then comment here as to the results.

Empty all the air from your compressor tank. This is a good time to test your compressor's PRV.

Once the tank is empty, try to start the air compressor. Did it start without popping the breaker?

Let me know as a comment here.

Cheers,

Bill

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will not run - is motor bad

by Daniel Hutchinson
(Honey Grove , Texas)

was working great next morning breaker was tripped so reset and broke again. took motor off and used ohms meter and connected to black and white lead and show , went from 1. to .003 and when i spin the motor by hand ohms would go up .120 and back down so is motor bad.help please

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Oct 29, 2013
bad motor?
by: Doug in s.d.ca

Can't tell from what you say.
It probably has at least one capacitor, which explains, perhaps, the resistance reading you got.

You should check the motor and cap(s) individually.

Turning the motor by hand makes it a generator, and that will change an "ohm" reading.

Since you already have the motor off, you might want to just go to a motor shop and let them check it. They will be able to get a comparable motor for you if it is bad.

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msm mark screw compressor wont start

by Bri
(UK)

Hi I have a msm mark screw compressor and it will not start no sound at all just nothing I checked the fuse but that's about it
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Howdy Bri... my, that is a nice looking compressor.

I visited the site to try and get a handle on what the issues might be. The site doesn't indicate whether this model is a continuous run, load and unlload, or a compressor that fills the tank and shuts off when the pressure switch cut out pressure is reached, and waits for the pressure to drop before it starts again.

If it is continuous run, the controls are more complex, but... you still need to check and see if power is getting to the motor circuit through the pressure switch.

I would dump the tank air until the pressure falls below the cut in pressure setting, then use a multi-meter (very carefully - 220 Kills) to monitor the power flow into the pressure switch and then past the switch to the motor. With the pressure below cut in the pressure switch should have tripped to ON, and power should be flowing.

If you are not comfortable with the process, you might be best to talk to the source...

As their website says under the Dealer portal "Starting from the serial number of the machine, you can find manufacturing data and product features. With this great tool, you have access to service kits, certificates, instruction books, part lists and other documentation! "

Cheers,

Bill

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Oct 08, 2013
msm
by: Bri

Hi, thanks for getting back to me so fast, I have had a look and I have found that the contactor is not pulling in and as soon as I push it in by hand it starts up!
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Good on you. So, the contactor spring is failing?

B.

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