Re: [CAD_CAM_EDM_DRO] 3-Phase motor running from Single Phase Supply ?

In a message dated 01-Jan-01 05:34:16 Central Standard Time,
chris@... writes:

> Here in NZ, it is common, although not universally standard, to have 3 phase
> everywhere, all of the street mains is 3 phase, and every third house gets
> the same phase.
>
> >All that said, I know of lots of machine shops in houses (mostly small
> >commercial job shops ;) ). They "get away with it" by keeping a low
>
> We have zoning restrictions etc here as well, although not as draconian
> sounding as yours... The "home business" scenario is pretty much open
> slather unless you have excessive traffic, noise or discharge (light, sound,
>

Chris: Surely some reading this will scream and holler, and disagree with
other untoward forms of protest, but know this: Here in the U.S., there are
regions where the "local government" details are draconian and 19th-Centurish
(see Bahstan, MA, etc.); but here in good ol' Texas (where the buffalo and
cowboys roam), in some "city areas" where there are "zoning restrictions",
you might have to watch your behavior, and it is possible that some
bureacrat-inspector who have moved down here from a "north-eastern State,
with a chip on his shoulder" would make trouble, even for a clean and silent
home-shop with only tiny "hobby machines", used on Saturdays between 11:00
and 16:00. But some of us have the fortune to live in Houston, or perhaps
better-yet, "outside the city-limits", where there are no such silly rules
(well, OK, maybe "deed restrictions" in hotsy-totsy "rich-boy
neighborhoods!), and a person can quietly do his machine-building, and export
to countries across the sea (Have! And will, any time someone wants summin!)
with NO problem! Three phase? Here, three phases "run around" near some
residential areas, but usually only along "main thoroughfares", and only
single phases "down the easements", behind rows of houses. I was lucky in
moving here, as my home-shop is back-to-back with a private school with
three-phase (they have tons of air-conditioning, a necessity, here!) so, I
only had to pay the utility to increase the size of the "pole pots" (that's
utility-personnel lingo for "transformers up the power-pole") so they could
handle the school and my 5KVA "worst-case load", and they did that in an
afternoon, and I have had "real" three-phase ever since. I have heard,
since, that the local power-company will not do this, any longer (supply
3-phase to a residence), even for money! But I have no confirmation, nor
real reason to believe it.

As someone in a musical once said, "It is a pondrement!"

Oh, no, the "stringing" of only 110 V. to houses, while perhaps occasionally
done 50 years back in rural areas, is not now done. Houses, even those with
only lights and an electric fan or so, are supplied with "center-tapped" 240
VAC, that center-tap being "neutral", also usually "grounded" ("earthed" in
English English). Then, "either side" is 120 VAC, for lighting, etc.
Kitchen stoves and most single-phase air-conditioning macines are 240 VAC
single-phase. 110 V. is no longer "nominal" in the USA, but 120 V. is. It
actually varies from 95 to 130, depending upon the season, phases of the
moon, how far one is "from the pole", how tight (the installer was when he
didn't tighten) the connectors, etc. I have a "line meter" in my office,
here, and that varies from 108 to 125 VAC, depending upon the season and
whether the AC is running, or at rest. It is nearly amusing to think about
it!




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