On Fri, 22 Feb 2002 08:17:03 -0800, Bob Ammerman wrote:

>Yes, quite a few places operate under the premise that the supply =
voltage
>(ie: the secondary of distribution transformers) is completely or nearly
>floating.
>
>This has the advantage that a single fault will not cause a problem.
>
>One example I know of where this was used was in a factory that used a =
lot
>of power. Rather than ground one side of everything it was all kept
>floating, and a light bulb was connected from each phase to ground. =
Under
>normal circumstances the three bulbs would all burn dimly.=20

When I was in the Navy (late 60's to early 70's), we had a floating 50
volt relay supply system that was run all over the ship. I don't know
if they still do this anymore but it seemed to me that every system on
the ship used that supply.

If either side of the supply got shorted to ground (and there are LOTS
of grounds on a metal ship), our systems would still work unless a
second fault grounded the other side of the supply. I spent quite a
bit of my time running down and eliminating 50-volt grounds. :=3D)

IIRC, the supply itself was a 100 or so amp brute located way down in
one of the snipe spaces.


Regards, Bob

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