Re: Quincy compressor/3-phase redux
- From: Bruce L. Bergman <blnospambergman@xxxxxxxxxxxxxxxxx>
- Date: Wed, 21 Nov 2007 23:51:55 -0800
On Wed, 21 Nov 2007 19:25:34 +0000 (UTC), Todd Rich <torin@xxxxxxxxx>
wrote:
Well, people were so nice here helping me through my compressor/power
woes, I figured I would let you know how it turned out.
After over a month of waiting for word from the power company as to what
their decision was going to be on my being able to get 3-phase, they
called me back yesterday.
They are willing to supply me with 3-phase power, but since they will need
to put a transformer on the pole, they want me to put a deposit down to
guarantee 5 years of service from them. Over the course of 5 years, they
will credit me for the distribution part of my power bill and at the end
of that time, they will pay me back the portion of the deposit that
actually used. As in if the bill was $200 for one month, about $75 of
that would be the distribution charge. After 5 years, I could get the $75
portion back. And yes, that is what I would have to use each month to get
back the $4500 deposit they wanted.
Actually, a separate 200A or 400A 120/240V 3-Ph Open Delta feed for
the shop doesn't sound like that bad of a deal, especially if you have
other 3-phase equipment in the shop like a lathe or mill that you'll
be running.
One thing that may affect your decision to install real 3-Ph is if
they will charge a lot more per KWH because it's a "commercial
service" with a demand charge adder - find out the rates first. If
you are doing work for hire that doesn't matter as much, plus your
accountant will like the separate meter since the power is an overhead
expense to itemize and write off.
Either way it is far better to have the shop on a separate meter and
feed, and even a totally separate transformer bank if you can. The
surges and dips will get back to the house and can mess up computers,
and both the neighbors and your wife will not be amused.
Even with the house main upgraded to 200A, starting up 15-HP motors
is going to blink the house. And if you are in the shop running a
plasma cutter or a big welder and the compressor kicks while the AC
and a lot of lights are on at the house, you seriously risk tripping
out the main.
So, while I was thinking about it, I looked on ebay and found this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=42922&item=290181630805
The 10-17HP seemed weird, so I called Baldor up. Turns out it is a custom
built motor, and from the data package they sent me, it appears that it
actually just a 15 HP single phase motor with long leads and a funny way
of stating it. But it should be able to run continuously at 15 HP, which
is what I need to run the compressor. (For those that weren't paying
attention, my compressor is actually a 20 HP model, but the motor was
replaced with a 15 HP one, which Quincy says will work, but a 10 HP motor
will not.)
It worries me that you didn't say what the duty ratings were for
that motor. A compressor needs a high torque start to get up to speed
before the unloader lets the compressor start pumping - a fan duty
motor isn't going to reliably start a compressor.
Well, for $107.50 + shipping (probably about $200), that seemed a much
better deal than $4500, so I went for it.
I'll have to make some adaptions to fit it, since it is a slightly
different frame and shaft size, but it looks doable.
Well, give it a try - if it works, great. If it works but you start
tripping out the house main, you may still end up putting in a new
dedicated service for the shop. (And buying SWMBO something big and
sparkly and really expensive for Christmas in atonement.)
--<< Bruce >>--
.
- References:
- Quincy compressor/3-phase redux
- From: Todd Rich
- Quincy compressor/3-phase redux
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