SpudFiles

Hey guys, back again

I was recently able to acquire an old AC compressor, the big scroll kind. It's a Copeland and apparently its real expensive new... but anyway, I'm wondering if anyone has ever used them successfully as air compressors. Doing google searches really only turns up car AC compressors.

The only downside is that this is a 230 volt compressor and it is missing the starting cap circuit... But if it's worth converting I may just shell out for the necessary electronics and find a way to give it 230 volts. I'm sure there's a 230 volt outlet somewhere at my house.

Appreciate any input! Thanks

As far as I know, most refrigerant compressors are scroll compressors, if that answers your question.

Your house should have at least one 220v outlet. If not: http://www.askmediy.com/how-to-install- ... lt-outlet/

Interesting, I was under the impression that fridge compressors were single acting piston compressors... Thanks for the info though, hopefully I already have one somewhere!

I think the ratio of scroll vs reciprocating compressors comes down to number of fridges vs number of heat-pump/air con units.
Scrolls are used in heat-pumps/air-conditioning units where the temperatures don't need to be dropped as far in refrigerators. Refrigerators use reciprocating piston compressors to achieve the higher pressures required. As always, I'm sure there are exceptions. Both will be fine at pumping air though.

I have a small scroll compressor out of a heat pump dryer, but it has a capacitor that is a bit too small for it.

Comparing my scroll to my reciprocating, the scroll has a more steady and higher air flow rate and it feels like it draws a stronger vacuum. Above 100psi there is a noticeable decrease in the rate of pressure increase in whatever is being filled, maybe due to the capacitor? But this lines up with what I understand from industry.

My findings could be specific to the examples I have, best of luck getting yours working.

I actually have used a 240v compressor from a central air unit for filling my large cannon. With 120 psi going in it will put out 300psi at a pretty high flow and be under the current rating. Im sure you could produce higher pressures especially for short periods. Mine has no seperate start cap, it has one cap that stays in the circuit all the time for starting and running. If you can find what size cap to use and don't need that high of a pressure they seem to work well and provide much more flow than a fridge compressor. As far as the 240 just get a dryer cord, and fused switch and put some probably 10a fuses in it.

Thanks for that! I'll have to look up a spec sheet for it an find out what cap to use. Dryer cord sounds pretty simple as well! Cheers :occasion5:

I've always had success with any old start cap I find, starting under no load it's really non critical.

If you can find the current or wattage, you can usually eyeball what cap you need.

Need the high pressure for a new hybrid eh?

wdr0 wrote:As far as the 240 just get a dryer cord, and fused switch and put some probably 10a fuses in it.

And remember that in a 240V circuit both wires are hot.

If you find the spec sheet for the compressor it will say if it needs a start or a run capacitor. If running for a long time on a wrong sized run capacitor I think you run the risk of burning out the windings.

Zeus wrote:Need the high pressure for a new hybrid eh?

Not quite

Thank you all for the input, once I get it home during a break I definitely want to try it out!