Re: 3 phase 240v

[<davidmcalister@mindspring.com>]

If the generator puts out 240 VAC, 3 phase, there probably will not be a
neutral.  If there were, hooking from line to neutral *_will not_* give 120
VAC.  The voltage would be 138 V.  This might be OK for some 120 VAC
applications, but it is really too high.  What Sharkey is thinking about is
240 VAC, 3 phase with a stinger.  This has a neutral that is a tap at half
of one of the 240 VAC legs to give normal household 120 from either of 2
lines to neutral.  Beware as Sharkey said.  The other leg is 180 to neutral
(it may be B or it may not).

Bottom line, talk to the generator folks and find out what kind of
connection it has.

----- Original Message -----
From: "Sharkey" <sharkey@mrsharkey.com>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, June 26, 2002 7:04 PM
Subject: Re: 3 phase 240v


> Addressing the theory behind obtaining 120/240 from a three-phase source
> such as a generator:
>
> Connecting between any two "Hot" phases will give the equivalent of 240
> single phase power.
>
> Connecting from any one "Hot" phase to neutral will give 120 volt single
> phase. *CAUTION*: depending on the connection of the winding inside the
> generator (or utility step-down transformer), the "B" phase may be a
"wild"
> leg, with 180 volts-to-neutral. When connecting to any three-phase supply
> to obtain 120 volt single phase branch circuits, ***be sure to measure the
> RMS voltage before connecting equipment***
>
> Break-out "spider" boxes supplied with rented generators generally will be
> connected properly to supply the correct 120 and 240 volt power needed by
> contractors, stage lighting and PA sound reenforcement equipment, meaning
> it will also be safe for charging your EV.
>
> -S
>