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The Big Money
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Discussion Starter #1
I got an oil driven 100 litre compressor that when its filling up with air it just shuts down after 30 seconds. Got to go over and press the reset button on it a million times to get any job done these days. OK its 11 years old and I don't use it very much but when I do I want it to work right.

Whats wrong?
 

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Did you buy this compressor new? If not, I would start looking for a piece that looks after-market. A lot of old compressors burn up the relay or coil and this would cause it to turn itself off before reaching capacity. Sometimes people will try to replace these, but they can be difficult to find since most relay manufactures build them specifically for a compressor mfr. If you find out some specs I can get a quote to you....I work for Graybar Electric and I can get the relays from the mfr direct if that's what you end up needing.
 

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The Big Money
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Discussion Starter #3
I bought it new. I think its that button that I re start it with
 

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When I first installed my new compressor it started doing that, the wiring was too small and the breaker was too small so I made it all bigger.
One of my old junky pumps did that too. It was in desperate need of an oil change. I found out later that it was the rings falling apart, so I junked the pump and went with a cast iron one.
 

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The Big Money
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Discussion Starter #5
Just replaced the breaker on it and its still cutting out. What could it be?
 

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It's not here in front of me so I'll try and guess. First off are you pressing the thermal reset on the motor to start it? If so, that's your problem, the thermal reset switch should be replaced, or if the motor is that hot that the thermal reset is tripping, find out why.
Most of the time cutting out problems are caused by the pressure switch/relay. They're usually cheap enough to just replace, and if yours is 10 years old, a replacement is probably due. I'm just not sure what you mean by pressing reset.
 

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The Big Money
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Discussion Starter #7
Maybe its the thermal reset button that I am pushing, I don't know its name. And my compressor is getting real hot
 

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the thermal reset is a switch located on the motor. The compressor pump getting hot is normal. The motor should be warm, but not hot. A hot motor is usually a result of over stressing, (i.e. something is causing more resistance than it was designed to handle), or there is an internal problem with the motor (i.e. the bearings are starting to go and the armature is rubbing on the magnets, the windings are starting to short, etc.) How is the oil in the pump? Is the motor a serviceable motor (has oil receptacles at either end) or the maintenance free type?
 

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The Big Money
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Discussion Starter #9
Alright I've replace the thermal swithch and it is still cutting out. There is a small white canistor with 3 wires hooked up to it, tomorrow I am gonna replace that and see what happens
 

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Mine did that when I first got it. I was using an extension cord due to the lack of outlets in the garage. As soon as I eliminated that, it has worked fine ever since.
 

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Just one of the guys
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Hey Charlie...snap a pic of what yopu are pushing and what you are replacing. That would tend to help out somewhat.

Kevin
 

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The Big Money
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Discussion Starter #12

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I don't think you had to replace the start/run capacitor. When that fails it usually doesn't start at all, or runs at about 1/2 RPM. I still don't see a pic of what you are pressing to reset the motor. Is it the thermal reset? And how is the pressure switch? There should be a tube running in one end and a power cord running in the other. It adjusts the pressure limits for the motor to kick in and kick out, this isn't what you're resetting is it?
 

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So you're pressing the thermal reset. You are probably pressing this because your motor is very hot when it trips. It's getting hot because 1. you don't have enough voltage to run the motor. 2. The motor is worn and needs servicing. (your motor looks like it's a maintenance free one) 3.The compressor pump is giving too much resistance to the motor either because of wear, or some other factor that causes resistance.

Things to check:
Is the electrical socket you usually plug into at or around 120V? (or whatever voltage it's supposed to be at. There should be a plate on the motor telling you what voltage, amperage and frequency is required) Are you running an extension cord from the wall plug to the compressor? (that could cause electrical resistance losses) How far away is the wall plug from the electrical panel? (again resistance loss) Is the electrical plug and wires of the compressor motor in good shape? ( R.L) When was the last time you changed the oil in the compressor pump, and is it the correct viscosity? (Increased friction causing excess strain on the motor) How easily does the pump turn when you disconnect the motor drive belt? (try this with an empty tank and a tank with some pressure, but leave this one till you've exhausted everything else because it's a PITA. While you have the belt off, try running the motor and see if it still trips the thermal reset.) When was the last time you cleaned out the pump air filters? That looks like a pretty heavy duty motor, is the fan actually turning behind that shroud and is it free of debris sticking to it?

I hope you find the problem.
 
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