On Monday, November 25, 2013 4:26:14 PM UTC-5, Ralph Mowery wrote:
wrote in message

...



First of all, in North America, the typical p[ower supply is NOT 2

phase. It is center tapped single phase. You have a line1, a line2 and

a neutral - the neutral being shared between the two lines. If the

load is ballanced between the 2 "sides" there is no current in the

neutral. The neutral is regerenced to ground for safety reasons.



In early reural electrification in the USA, single wire distribution

was used - using "earth return" It worked, but was fraught with

problems, and is virtually unheard of today..





You might as well forget trying to explain that in most of the US the power

comes in to the house as a split single phase.


I don't see anyone here denying that it's called "split-phase". The
transformer splits a single PRIMARY phase.
What generally happens when you split something? Do you still have
just one? What's at issue is that you have two legs that are
180 degrees out of phase with each other. That simple true statement
is where all the diagreement began. You can see two voltage waveforms
180 deg out of phase on a scope.
If they were not out of phase by 180 deg, you would not get 240V.
Here, from two electrical eqpt manufacturers that talk about two
phases, 180 deg out of phase:

http://www.samlexamerica.com/support...Circuit s.pdf

http://www.behlman.com/applications/AC%20basics.pdf


And the IEEE clearly agrees that there are in fact two phases present.
From a paper presented at a recent IEEE power engineering conference:

http://ieeexplore.ieee.org/xpl/artic...number=4520128

"Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees."


Are IEEE power engineers and electrical eqpt manufacturers wrong?

I'm still waiting for someone on the other side of this to give
their definition of "phase" and why if one can see two phases on a
scope, there are not in fact two phases present.