'Nuther Air Compressor Question

[Doppleganger]

Ok, without going into details as to how this occurred....here it is: I was going to run my compressor off my generator (still might but for a number of reasons wont if I dont have to) for 220 that my garage doesn't have. There is a generator receptacle on the side of the house that I use for back feeding the generator and running the house when the power goes out. I had an idea of how to run my compressor off of that receptacle from the house. I wired a 220 plug in the garage with a twist lock receptacle, so that instead of plugging the extension cord into the generator to back feed the house, I plugged it into the plug in the garage and got 220 FROM the house. Neighbor down the street does this with a welder.

So I try it out and it seems to run fine, except after about 10 min the compressor motor (I think) wants to stall, so I turn it off immediately. Trying it again with a meter (it will run fine for about 5-10 min) it shows the power at the motor drops from 220v to about 200v. My guess is the 10ga wire run (100-120ft) is too long for the amp draw of a 5 HP compressor. NEMA shows 150ft as doable for stoves, heaters, etc but never mentions an air compressor.

Plan B thought: I have a 30 gal compressor that is 110v, half as loud and works great. Was thinking of plumbing it into my 80 gal tank and pressurizing it with the the 30gal compressor. Or, maybe just using the 80 gal as a storage tank for the 30?

Just thinking out loud - was hoping someone who had BTDT would chime in. I need to get my cab into primer and am running out of time and ideas. Heck, just the 30gal might be fine for that.

Thx

 

[Grit dog]

My 5hp single phase 220v belt drive compressor has been running for years on a couple hundred ft of 10ga and a 30A breaker in the sub panel.
I think there’s something wrong with your setup and won’t even comment on the janky “back feed the house during power outages” setup.
Presume you’ve proven that this condition doesn’t happen when running the compressor off of the genny and a short cord?

 

[Doppleganger]

My 5hp single phase 220v belt drive compressor has been running for years on a couple hundred ft of 10ga and a 30A breaker in the sub panel.
I think there’s something wrong with your setup and won’t even comment on the janky “back feed the house during power outages” setup.
Presume you’ve proven that this condition doesn’t happen when running the compressor off of the genny and a short cord?

When I tried if off the generator with a 40ft cord it ran fine. Would be easier and much more quiet to run it off the house though.

And the 'janky' setup includes a transfer switch on the box inside. Transfer switch on = feed from the gen. Switch off = 220 circuit (initially ran for central AC that was never installed). When/if it ever is, the transfer switch and outside receptacle will go away.

 

[Grit dog]

Ok my apologies then, you didn’t mention that you had it hooked thru a transfer switch. Thats mo’ safer.
Here’s an idea, presuming you’re planning on running power to the shop at some point.
If you’ve calculated the voltage loss and it makes sense with what you’re seeing (You don’t say, but is your 10ga “extension” stranded wire like an extension cord or solid wire? Solid carry’s more amps for the same gauge), then maybe buy the wire you need for the shop, make up suitable plugs on either end and use it (6 or 8 ga). Then store it out of the sunlight until you’re gonna use it for permanent install.

 

[Ricko1966]

Using the 30 gallon to fill the 80 gallon is a decent idea. I have a similiar setup for when I need lots of stored air. Only problem is recovery time. I actually stole the idea from roofers. Look up air pig. They run the compressor hose to the air pig, then they plug their tools into the air pig. I have a 60 gallon 5hp and an 80 gallon air pig. Found you a pic

 

[Doppleganger]

Thanks @Ricko1966 - DL'd those pics for future use. A friend of mine has a 110 gallon spare air tank in his garage (unused). If I ever get a place with a shop I'm going to try and pry him out of it. lol

@Grit dog - this was solid core wire - no reason why it wouldn't work, unless the run was too long....which your setup alone proves that not the case.

HOWEVER....think we found the issue. A buddy's SIL is a commercial electrician - got him to stop by and do some finagling. Seems I have a bad pressure switch - only thing I never replaced. Not only did it leak but was taking 233V and turning it into 189-201v. wtf?

Thanks much fellas!

 

[Ricko1966]

Thanks @Ricko1966 - DL'd those pics for future use. A friend of mine has a 110 gallon spare air tank in his garage (unused). If I ever get a place with a shop I'm going to try and pry him out of it. lol

@Grit dog - this was solid core wire - no reason why it wouldn't work, unless the run was too long....which your setup alone proves that not the case.

HOWEVER....think we found the issue. A buddy's SIL is a commercial electrician - got him to stop by and do some finagling. Seems I have a bad pressure switch - only thing I never replaced. Not only did it leak but was taking 233V and turning it into 189-201v. wtf?

Thanks much fellas!

It was about to turn 233volts into fire.

 

[Doppleganger]

Anyone know a GOOD pressure switch brand?

I have heard the 80 gal cutoff at 150psi - think my 30gal cuts out at 130psi.

 

[squaredeal91]

Using the 30 gallon to fill the 80 gallon is a decent idea. I have a similiar setup for when I need lots of stored air. Only problem is recovery time. I actually stole the idea from roofers. Look up air pig. They run the compressor hose to the air pig, then they plug their tools into the air pig. I have a 60 gallon 5hp and an 80 gallon air pig. Found you a pic

I have a setup like this I made from an old c&h compressor. Took off pump and motor and it goes to my emglo gas compressor I use with sandblasting and other outdoor things.