3 May
2004
3 May
'04
4:14 p.m.
On Mon, 3 May 2004, Patrick Finnegan wrote:
On Monday 03 May 2004 22:14, Tony Duell wrote:
Tony is right here. At least in Indiana, Illinois, and the Code Book,
208 three-phase is a "Y" setup with 120V from each phase to neutral,
and 208V from phase to phase. 240V three-phase is a delta setup, with
the neutral half-tapped between two phases, giving 240V phase-to-phase,
Wait a minute! By definition, a delta configuration can have no
neutral. Else it is no longer delta.
- don
208 is
really a 240 volt 3 phase system measured in a star
Is it? I'd assumed it was 120V neutral-phase, which is then 208V
phase-phase. 120V phase-to-neutral on two of the phases, and 208V
phase-to-neutral
on the third one. It's important to realize when wiring a system like
this that the third phase is NOT 120V to neutral like the other two,
I've heard of some people (idiots) ignoring that, and having issues
when they tried to turn on their 120V lamps they just wired. : )
Agreed.
Pat
--
Purdue University ITAP/RCS --- http://www.itap.purdue.edu/rcs/
The Computer Refuge --- http://computer-refuge.org
I have
not looked at any 3 phase power supplies for computers, but
I would bet they are 240 volt 4 wire and don't bother with the
neutral at all, just 3 phases and a ground.
Not at all. A very few PSUs are genuinely 3-phase, and some large
disk drives have 3 phase motors. But in the case of DEC machines at
least, the individual PSUs are single-phase units run between a phase
and neutral (star connected). Of ocurse the load is approximately
balanced between the 3 phases (or it is if the machine is configured
properly).