I’m in need of more air for my shop… I have one compressor plumbed in now, and another in the shed not in use. I’m wondering if I cant just hook them up in parallel to create more volume. Anyone see any problem with this? Will
I damage them by possibly allowing air to flow into the tanks rather than out? Any suggestions?
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There's only one problem connecting two compressors together. If the bottom settings aren't precisely the same, one compressor will always be doing the work to recharge - think about it.
There is no problem reversing air flow - makes no difference.
Now even though connecting the compressors will result in only one pump recharging the system, you will benifit from a larger volumn of air. I have an old tank (pump died) that I tie in-line with my shop compressor. It serves as extra volumn so when I spray or use air ratchets, I have plenty of reserve air.
Essentially by coupling two compressors you'll end up with a system like I have.
MG
PS, you don't have to do a fancy pipe job. All you need it to couple the additional tank/compressor is a 'T' anywhere along the incoming line. The pressure will equalize. Just one pipe too - no in-and-out sequence of pipes.
There's only one problem connecting two compressors together. If the bottom settings aren't precisely the same, one compressor will always be doing the work to recharge - think about it."
Mike,
If one compressor is not keeping up, the second will kick in as demand requires, otherwise why would one need a second? Lots of shops have dual compressors set to kick in and out at differing PSI's. IMO, it would be bad from a voltage drop perspective to have them both kick in at once.
Now if this is a one or two man show, a good single TWO STAGE compressor should be more than able to supply all the air one needs WAY MORE efficiently that two single stage compressors running in tandem. So IMO, sell the undersized unit and get what you really need, or keep the old one as an unattached back-up.
WSJ
Edited 11/20/2004 11:21 am ET by WorkshopJon
I suggest putting each compressor on a different circuit breaker. I have three small compressors and have toyed with the idea of doing this for some time, using three compressors to keep ahead of a crew. Since I started working alone, I have not needed the extra capacity.Les Barrett Quality Construction
You are right. Good point. I guess when I've set up dual compressors I really didn't tap the output of the primary so the secondary never kicked it. So much for my limited experience.MG
Either on different breakers or on one that can handle both. Then wire both compressors to a single pressure switch on one of the machines.
Gary
http://gwwoodworking.com/
Then wire both compressors to a single pressure switch on one of the machines."
Gary,
How does that elliminate the voltage drop? The two breakers still feed off the same main.
WSJ
My electrical contractor friend says, "Unless the compressors are 'huge,' or the service main is small, then there shouldn't be an excessive, damaging voltage drop if both start at the same time. But why can't you put one on a 5-second delay?"
My 3-phase, 7.5-hp saw and 1-phase, 3-hp dust collector start simultaneously, and have for years, without any apparent problem or damage. They are, of course, on different circuits and two different and fairly large main services. Are you running on a single service drop?Gary
http://gwwoodworking.com/
My 3-phase, 7.5-hp saw and 1-phase, 3-hp dust collector start simultaneously, and have for years, without any apparent problem or damage."
Gary,
Your saw doesn't have a board in it attempting to be cut when it starts up does it? Most very large air compressors have a blead off or even a clutch so that they don't draw full amps till they spool up. The smaller ones don't, and draw the most AT start up.
WSJ
I wouldn't want both compressors kicking in at the same time. This would be a heavy startup load for the circuit and it would be hard on the motors as they would unnecessarily be starting up at a lower voltage.Les Barrett Quality Construction
ian,
We have had two compressors hooked up like that at my business for 15 years. Never have had a problem. The presssure switches are close enough that they always both come on within a matter of maybe 20 second of each other and cut off at almost the same time also. We have a glass bead booth that uses a LOT of air and that was the easiest solution at the time. Has worked real well for us. The two compressors are next to eachother and are tee'd together.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
I guess I could clarify my situation.... This is NOT a production shop. I build a few cabinets now and then, build stuff for my personal use, and work on my cars. The main reason for more capacity is running air grinders which consume alot of air, and my current compressor cant keep up. I dont do this very often, so I'm not sure an investment in a new compressor is justified.
What's the difference between a single and two stage compressor?
It sounds like I'd be fine running these together with the backup compressor set a bit lower kick in point (and I certainly will run them on separate dedicated cucuits.) I think you could avoid excessive voltage drop by running the circuits on opposite legs in the panel, even if they did come on at the same time, and this would also balance the electrical load.
Thanks for all the excellent input. I've just started using this site in the last couple weeks, and feel more educated already (I'm sure the abuse will start any day now.)
What's the difference between a single and two stage compressor?"
Ian,
The mechanics aside, two stage compressors operate much more efficiently as pressure builds. Single stage ones bog down and consume lots of power for the amount of air they are moving as tank PSI's increase.
A good two stage of equal HP can often supply double the amount of air at a given PSI than a single stage can AND consume less power doing it. They just cost more upfront. A bonus is that for a given size tank, they hold quite a bit more air, usually 175PSI
WSJ