Compressor woes

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Downwindtracker2
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Re: Compressor woes

Post by Downwindtracker2 »

My compressor started to blow oil out the crankshaft seals . It was a 3hp 10cfm Speedaire . So I replaced the pump with a Rolair 3cylinder 3 to 5 hp. I changed the sheave on the motor to run it at the lower suggested rpm. Doing the math, I thought about 15 cfm. When new, the motor got warm and I had lots of air. After not too long, the motor didn't warm up any more and I had about the same amount of air as before. Maybe the Chinese made pump quality isn't that great ! Even the US made ones have Chinese made components.
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Ironman1
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Re: Compressor woes

Post by Ironman1 »

Spro is right, it is junk now.
If you have ever taken a piston compressor apart you will find it does not have any oil control rings. Compressors are designed to pump against pressure, and with a blown out hose they will pump out all oil and seize. I have seen this happen more than once. People get cocky because they think they have no leaks so leave it on. This always ends badly.
I have a light in my shop that is on when there is power to the compressor, and when I shut off the switch, the power is cut to the compressor and the shop light is off.
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Steve S
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Re: Compressor woes

Post by Steve S »

That's great you were able to repair it . I had a 60gal Craftman I picked up used , one of those oil-less types . I paid 300 for it , the compressor had been replaced under warranty already . It lasted for years , I was sanding down a boat hull when I lost air . A trip down to the cellar I found the compressor had gernaded into a dozen pieces . Lucky it was positioned in the corner of my shop and the block walls contained the metal shards . I had to explain to the wife how the compressor is the heart of the shop . What convinced her was every time she wanted something fixed or made , I said "no can do momma" need a compressor .... Eventally she gave in and I got the green light , picked up a new Kobalt model . Planning on turning the old 60gal tank into a rocket stove for the shed .
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Bill Shields
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Re: Compressor woes

Post by Bill Shields »

my timer pulls in the coil on a 240 v motor starter to control the compressor
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spro
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Re: Compressor woes

Post by spro »

So it isn't running all the time, no matter what..? :)
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Bill Shields
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Re: Compressor woes

Post by Bill Shields »

correct...timer kicks off after 20 minutes. short the timer 'reset' connection and it begins counting down again.

timer is started with a door bell push button on old-fashioned telephone wire strung all around the shop.

I have maybe a dozen of them scattered around the basement and out in the garage - basically one at each air hose connection + a few others based on 'where I work'.

Push the button (short the lines together), contactor pulls in for 20 minutes & compressor starts

When timer runs out, the contactor drops out with a noticeable CLUNK that I can hear anywhere in the basement.

If I still need air, I just push any button and the contactor pulls back (CLUNK) in and the compressor will start on air demand @ low pressure.

Has become automatic reflex like Pavlov's dog -> if I am standing at a machine and will need air and I hear CLUNK, I just reach out and 'ring the bell'

when I am running the shot blast booth, I have an 'manual override' button - (7' in the air where my wife cannot reach it) that pulls in the contactor and ignores the timer.

Once of these days I will fix up the blast booth so that when I have the booth vacuum running it bypasses the timer, but it is one of those 'roundtoit' things that costs me nothing to leave as it is....

light switch that controls compressor is a good idea..except when need air in garage there may not be anyone in the basement -> and it would be nice if I could get my wife to turn the basement lights off once in a while.....except when I am down there working....!!!!
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spro
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Re: Compressor woes

Post by spro »

Really cool Bill. I'm a moron for not doing something similar. My main compressor is deep in the back of the garage. Sometimes, some weather it isn't easy to navigate back there to turn it on. It is already piped with an outside output chuck.
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Bill Shields
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Re: Compressor woes

Post by Bill Shields »

using the latching timer is the trick. Just short out the 'reset' terminals and it closes and winds down and opens.

Seemed $$$ at the time ($100 Omron timer that can be made to do a dozen different things)...but turned out to be one of my better blacksmith moves.
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John Hasler
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Re: Compressor woes

Post by John Hasler »

I need to do this.

Improvement: wire an aux contact on the pressure switch (add a relay if needed) to reset the timer when the compressor is actually running. That way it will never shut off while you using enough air that the compressor is never idle for 20 minutes.
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Bill Shields
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Re: Compressor woes

Post by Bill Shields »

Adding the aux contact is not a good idea with the real world possibilities that exist around our farm:

Your idea means that if the compressor is running it will automagically reset the timer and continue to run forever, which is not what you want....if you have a leak and have walked away, the compressor will run forever...go back to beginning of thread...

examples being a wife that puts the tire air chuck down on the lever (drops on the garage floor and drives off because she is in a hurry) and it starts to bleed..or as we had a few years ago a rat that got into the garage and decided it liked to chew through the rubber hose...because someone left it laying on the ground (see beginning of paragraph).

On the realistic (handy) side, I frequently open the water valve on the bottom of the tank and let it dribble down the drain and walk away at the end of the work day -> knowing that the residual air pressure will clear the water from the tank...and the compressor will always stop.
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spro
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Re: Compressor woes

Post by spro »

Good stuff. If we are getting to where it looks like, that timer can also open the drain valve. That is the way all the commercial compressors for pneumatic control valves worked in buildings. Set times and periodic bleeding the tanks (and they do bleed water, lots of it) sent water in troughs to drains. but everybody knows this. What we don't know is that the cycles allow pressure in the tank and that could send the water through the wall outside. The pipe would be insulated and have a bend (colder temps) Nothing like a good idea blocked by ice. A container is enough.
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Bill Shields
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Re: Compressor woes

Post by Bill Shields »

probably not on this timer since while it will do many things if programmed, will only do one thing at a time, and in this case count down to 20 and open a contact..

sure, you could have the open motor starter contact drop out a NC solenoid to drain the tank, but that could potentially have the drain valve open a dozen times a day, under full tank pressure, which at my place would be a bit messy since 'outside' is not possible.
Too many things going on to bother listing them.
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