Re: triping circuit breaker

"Bruce L. Bergman" wrote:

On Sun, 08 Jul 2007 22:11:02 GMT, "Karl Townsend"
<karltownsend.NOT@xxxxxxxxxxxxxx> wrote:

Your friendly neighborhood power company will gladly install a
separate 3-phase service for you if you have a legit need for one
where single-phase won't cut it - and a "Well Service" certainly
qualifies. Might even get a better power rate for that service.

i WISH i could get real three phase. The closest three phase power line is
three miles away. Other shops around here have had estimates of $20K per
mile to pipe it in. Not going to happen.

Don't go defeatist on me yet - you haven't really tried. ;-P
As the Old Philosopher said "Never give up, Never Give Up that Ship!"

http://www.search.com/reference/Eddie_Lawrence

When the mere mention of your name in the Power Company executive
board room is met with curses and derision, THEN you can say you've
tried. You have reached the people with the power to say Yes and make
it happen, and if they still said No you made life uncomfortable for
them for a while. And yes, now they know your name.

Is the VFD option with single phase input also not workable?

You can do it that way, but the extra conversion losses in the VFD
are going to cost you. The only way a VFD would make sense is if you
were going to vary the pump RPM to match the water flow and pressure
you need, and save power making extra pressure you don't need. Could
be done, but it violates the 'Rule of KISS.'

Not to mention the well pump motors have to be designed and
nameplate rated for "Inverter Duty", and for submersible pumps that
aren't normally run on a VFD I doubt they're available. Though
stranger things have happened...

Three phase submersible pumps running on inverter drives are pretty
common actually, particularly in solar pumping setups.


Three phase motors are the most efficient way of converting
electricity to rotational work performed, period. But if you have to
manufacture that 3-phase with a RPC or VFD, there goes your
efficiency.

I think in this case, reliability trumps absolute efficiency and if the
efficiency gains of a three phase pump are canceled by inverter losses
it's a wash. I still think three smaller three phase pumps running on
three smaller VFDs is the way to go. Should be able to fit three 5HP
down the same hole as one 15HP and get triple redundancy and the ability
to drop units off-line entirely when water demand is lower.


And for some uses, 3-Ph is a necessity - I have never seen a 1-Ph
passenger elevator pump motor yet, real bad things happen if the pump
starts backward and (though rare) it can happen on a 1-Ph motor.

I'll check every irrigation well outfit to see if I can get another 15 horse
1 phase pump or get the one I own rebuilt.

Time to start rattling some doorknobs and making a little noise,
which might include filing a complaint with the state Public Utilities
Commission, or whatever they call the regulation/oversight body. The
utility not supplying you with what you need is silly.

Have you ever seen any behavior from a utility that wasn't silly?


Gee, that's precisely why the Rural Electrification Administration
(now the USDA-RUS) was formed, because the for-profit utilities
wouldn't invest in the outside plant to get the power you need to
where it's needed. Find the local office, they might be interested in
this problem, too - especially if they financed the line that heads to
your farm now with an REA Loan...

http://www.usda.gov/rus/

You are running a business and you need 3-Phase to run heavy motor
loads like the well pump properly, and the utility is only fooling
themselves if they think they don't have to run that third leg to your
site. (One more leg if you are connected Delta - they need two more
legs if you are hooked up Wye to ground.)

And if you have other neighbors with shops and farms that also need
3-Ph power for their wells and equipment, go document it. A list of
names and expected loads - let the utility break it down into dollars.

They tried asking as individuals over the years, and were turned
away - now you need to ask again, but as a proven group of willing
buyers. It will strengthen your hand if you can prove enough load
exists at the end of that leg to make it worth their while to run it,
the power revenue will pay back the cabling investment.

If the utility tries to stonewall or charge a small fortune for the
line extension after you prove there's a valid need, that's the time
to have a consultation with a lawyer who is familiar with your state's
utility laws and processes, state and county regulatory bodies, and
the REA/RUS federal policies. Call the state bar, they can find him.

Sometimes all you have to do is call the utility to talk to someone
in the President's Office and drop a name to prove you are serious
about this ("I'm talking to Joe Lawyer about this tomorrow...") and
they'll stop BSing you and shift to "Git 'Er Done" mode.

Sometimes finding a politician who needs a few PR points with the locals
for their pending re-election can help.


Even if you get them moving on it right away it will take them a few
weeks to do the engineering, order materials, schedule the crews,
upgrade the poles and cross-arms where needed, and string the extra
wires.... And it'll take you about the same time to get the new
service panels ordered, installed and inspected, order the new pump
and panel, and have the well guys trip the old pump out and the new
pump in.

--<< Bruce >>--
.

Relevant Pages

  • Re: 1 VFD--2 Motors can it be done?
    ... the use is intermittent I want to power my drill press as well. ... the vfd and twist lock plugs to the DP and Blower fan. ... which motor it drives as long as its within its capacity, ... I'm also not sure how the torque drops off when you ...
    (rec.crafts.metalworking)
  • Re: Almost got lucky with the VFD...
    ... power, not just 3 phase. ... You'll shorten it's life and end up with a nfg VFD, ... Hurco manual says this is a 4HP motor, not a 3HP as some have indicated.) ... I use a 10HP VFD single phase on my 7-1/2HP lathe motor. ...
    (rec.crafts.metalworking)
  • Re: How to set up VFD to properly control KBC bench mill.
    ... with all three legs going to the motor.. ... Maybe even as much a second or two; see what the VFD Fine Manual ... could keep it running for a second or so after the power line is cut. ... The 3 wire interface is an industry standard motor control interface. ...
    (rec.crafts.metalworking)
  • Re: How to set up VFD to properly control KBC bench mill.
    ... with all three legs going to the motor.. ... Maybe even as much a second or two; see what the VFD Fine Manual ... could keep it running for a second or so after the power line is cut. ... The 3 wire interface is an industry standard motor control interface. ...
    (rec.crafts.metalworking)
  • Re: Best practice for mill VFD control wiring
    ... E-stop circuit killing power after the drive to the motor, ... contacts on the contactor between VFD and motor go to drive enable. ...
    (rec.crafts.metalworking)