Hi, Kim.
208 is brownout conditions for a 230 volt motor. I saw another post
suggesting that the compressor won't be working as hard, but you also
must remember that at 9000 ft, the cooling ability of the air is down
as well. Don't do it would be my recommendation. The motor will
suffer from a very short life.
Possible solutions are a step-up transformer (lotsa bucks, lotsa
weight, lotsa loss); a 208 volt three-phase motor to suit (5 HP,
3-phase, 208-230/460V, TEFC, 3500 RPM motor, (for example) Grainger
stock #3N559 looks like about $250.) Hmmmm. That's all I can think
of unless you want to get a single-phase motor, which would be less
efficient and cost about the same initially (another Grainger example:
5 HP, 3450 RPM, 208-230V, single phase "Commercial light duty" air
compressor motor (# 4FG52) looks like about $200.) Oh. I see there
are two suppliers -- are their motors single-phase or three-phase.
Again, operating efficiency will be different.
Your system would be described as "three-phase 208-wye-120", commonly
used to provide a boatload of lighting/utility circuits in a
commercial (but not industrial) building. (The third leg of a three
phase delta 240 would never be used in such a building, so it's a
wasted wire!)
HTH,
Donald.
> From: "Kim Knapp" <kimknapp@vail.net>
> Date: Fri, 12 Oct 2001 22:59:56 -0600
>
>
> I didn't think my original question would create so many speculative
> answers! SO, I decided to trust noone and just measure what is coming into
> one of the panels. There are four BIG wires feeding the panel that I
> uncovered. One wire is Ground (neutral). The other three are each at 120v
> (almost exactly) from ground. Between any two of these three I measure ---
> you guessed it --- 208v.
> So, back to my original question which was; what does the group think about
> running a compressor rated for 230 on 208. Unfortunately, Ingersoll-Rand
> says no. Campbell Hausfield says no. Sears (FWIW) says no. Someone suggested
> looking at the motor plates. Last time I was at Loews I looked at the motor
> plates on the compressor they were selling (don't remember brand) and it
> said 230, not 208-230.
> So, I am now down to American IMC(Bel Aire) and Northstar (Northern Tool's
> brand?), which are specifically rated at 208 to 230. Anyone have experience
> with either of these? Efficiency is very important, since up here at 9000'
> we are already down by over 25%. I currently have an Emglo rated at about
> 13cfm delivered at 90psi and when run an 8 or 9 cfm tool the compressor runs
> continuously and pressure still drops!
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