Good point. Also consider center-tapped -to-ground transformers and the
infamous hi-leg, while not quite as hazardous, these can also wreak havoc
for troubleshooting electricians and novice designers.
Since we have these scattered around the more remote parts of Florida,
Russia must have all of the above, and then some..

Chris

ps:

What's up with your mime headers, Lawrence? Interesting how yours starts a
trail of mails without 'em....

c

> There is still a lot of so-called corner grounded Delta in
> St. Louis, Mo and
> other older sections of some other towns.  This arrangement
> causes havoc
> with all kinds of things, from computer equipment to
> remodeling and adding
> juice, because it is obsolete.  You probably won't see corner
> grounded delta
> in a new system ever.
>
> Modern systems do run a specifically grounded wire with the
> phase wires, but
> some of these WWII relic corner grounded delta systems didn't.  If the
> connection of one phase to ground fails, the whole system can
> begin to float
> up to high voltage, say from leakage from a high voltage
> transformer or even
> static. Often this ground connection is just a slim chunk of
> thin wire to a
> ground rod. You could literally have 440V in a plant, but each leg is
> several thousand volts to ground.  Eventually a motor or two fails on
> insulation, and the whole thing goes up in smoke without ever
> blowing a
> breaker, or motor cases become live at 4000 volts without
> shorting to ground
> because all the conduit is rusty and there is no ground
> cable.  Meanwhile,
> the electrician trying to work on it thinks it is normal
> 440V, and fries his
> brains out because he shoulda been using a hotstick.  Nobody
> likes corner
> grounded delta, but they are still around causing trouble.
> This nightmare
> schenario is why these things were owtlawed before I was born.
>
> --Lawrence
>
>
> ----- Original Message -----
> From: "Anthony Bussan" <TBUSSA@WOODWARD.COM>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Tuesday, June 18, 2002 1:56 PM
> Subject: Re: [EE]: Russia 380VAC three phase power Delta or Wye?
>
>
> > Wye doesn't have to have a center tap to neutral if the
> phases are loaded
> > correctly.  With Delta, I don't know what you mean by
> "center tap of one
> > phase."  And I definitely wouldn't connect any phase to
> neutral on delta
> > unless you like to see a lot of sparks.  A direct
> connection to ground
> like
> > that will probably blow apart your whole fuse box and take
> you with it.
> >
> > Anyway have fun,
> > Tony
> >
> > -----Original Message-----
> > From: Bob Blick [mailto:bblick@SONIC.NET]
> > Sent: Tuesday, June 18, 2002 1:40 PM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: [EE]: Russia 380VAC three phase power Delta or Wye?
> >
> >
> > > Just courious, what is 'wye' ?
> >
> > Hi Tal,
> >
> > Wye takes one leg of each phase and connects to neutral, so
> you have three
> > "hot" legs and one neutral in the center. Sort of like the
> letter "Y".
> >
> > Delta connects the three phases in a loop. Neutral is
> usually the center
> > tap of one phase, or one corner sometimes.
> >
> > Cheers,
> >
> > Bob
> >
> > --
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