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Compressor Question

Johnwa said:
I have a compressor exactly like @Tom O . I believe it is 10 US gallons. It has a 1hp motor. It’s reasonably fast to pressure up but like Tom’s it’s past it’s best before date.
IIRC it cuts out at 125psi and in close to 100.
Click to expand...

John,

What size is the motor pulley and drive belt?

Thanks,

Craig
 
Craig
the OD of the motor pulley is about 1.75”. It uses a Poly-v belt that is marked BT32
Also the motor is 3450rpm
 
Johnwa said:
Craig
the OD of the motor pulley is about 1.75”. It uses a Poly-v belt that is marked BT32
Also the motor is 3450rpm
Click to expand...

3450 RPM:eek: Are they typically that fast? Maybe my 3/4 HP 1720 RPM motor isn't going to work for this?
 
Most of the small compressors and table saws for that matter that I’ve run across use 3450rpm motors. Mine would occasionally stall on on a restart and trip the breaker. I think that was largely due to the check valve leaking but in any case it did work the motor. With a slower motor and less hp a 2.5”OD might work. You might have to make your own pulley though.
 
Johnwa said:
With a slower motor and less hp a 2.5”OD might work. You might have to make your own pulley though.
Click to expand...

Hmmmm..... I see what you mean about having to make a pulley now. This compressor is labeled 2 HP.....with a 20 gal tank, 150 PSI. Too much for 3/4 HP motor? What direction does your motor spin in? I'm thinking this needs to turn CCW?
 
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Johnwa said:
From the pulley end the motor turns CCW.
Click to expand...

Do you think it really matters which direction you turn the compressor pulley? The spokes on the compressor pulley look like a propeller that would force air across the cylinders if it were turned CCW. The pulley is labeled "This Side Out". I'm replacing the compressor pulley with a V-Belt pulley for now, so no propeller effect.
 
I’m not sure how the valving works in a compressor. Running backwards might pump air out of the tank but I don’t know that.
I do have a single cylinder in my junk box. It has a v pulley. You can have it if you want.
 
Johnwa said:
I’m not sure how the valving works in a compressor. Running backwards might pump air out of the tank but I don’t know that.
I do have a single cylinder in my junk box. It has a v pulley. You can have it if you want.
Click to expand...

Single cylinder? As in a compressor head?
 
Yes. OD of pulley is 8.75”
560646EB-E9FD-4D05-B678-C7E1514AF59B.jpeg
 
Johnwa said:
Yes
Click to expand...

John, what dia is the compressor pulley on your machine? This one is 10" but I don't know what the original motor RPM and pulley dia was.

I finally got my 3/4 HP motor, some pulleys and a belt mounted. I wanted to see what the compressor head is doing before putting any more effort into this thing. I ended up with a 6" compressor pully and a 3" motor pulley which makes for a 860 RPM compressor with a 1720 RPM motor. A little fast I'm thinking. In any event what happened was the motor would run for about 20-30 seconds and then stall. After much head scratching I disconnected the head from the check valve and away she went putting out a good volume of air. From the top of the head I could see the reed valves working away so those appear to be intact. I pulled the check valve and it appears to be blocked in both directions? I'll source a replacement tomorrow. If a 2 HP motor makes for 150 PSI one would think a 3/4 HP should at least put 50 PSI in the tank? If that proves out, I'll consider mounting my 2 HP motor on it.

Craig
 
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YYCHM said:
John, what dia is the compressor pulley on your machine? This one is 10" but I don't know what the original motor RPM and pulley dia was.

I finally got my 3/4 HP motor, some pulleys and a belt mounted. I wanted to see what the compressor head is doing before putting any more effort into this thing. I ended up with a 6" compressor pully and a 3" motor pulley which makes for a 860 RPM compressor with a 1720 RPM motor. A little fast I'm thinking. In any event what happened was the motor would run for about 20-30 seconds and then stall. After much head scratching I disconnected the head from the check valve and away she went putting out a good volume of air. From the top of the head I could see the reed valves working away so those appear to be intact. I pulled the check valve and it appears to be blocked in both directions? I'll source a replacement tomorrow. If a 2 HP motor makes for 150 PSI one would think a 3/4 HP should at least put 50 PSI in the tank? If that proves out, I'll consider mounting my 2 HP motor on it.

Craig
Click to expand...
I’m out of town until Saturday. I had to repair the leaking check valve on mine A replacement costs more than the compressor is worth

YMMV
 
A check valve shouldn’t be that hard to fix or make try cleaning it out and reseat the ball.
 
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