Re: IS 240VAC two-phase - NO

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Bert Hickman <bert.hickman-at-aquila-dot-net> 

Allan,

Well, I've got to disagree with you. There are two schools of thought here 
regarding electrical power, and you'll find that even some experienced 
power engineers may argue over this.

However, I would think that the most meaningful answer comes by looking at 
how multiphase power is actually generated. A single phase generator has 
one pair of windings located at 0 and 180 degrees. A two phase generator 
has 2 pairs of windings, one pair at 0 and 180 degrees and the other at 90 
and 270 degrees. Similarly, a three phase alternator will have three pairs 
located at 0 and 180, 60 and 240, and 120 and 300 degrees respectively.

I cannot agree that, by applying single phase AC to a centertapped 
transformer, you'll get two phases at the transformer outputs - they are 
still single phase, but one is in phase opposition (180 degrees) to the 
other. Tesla's initial polyphase motors and alternators had two phases - 
separated by 90 degrees. And early AC polyphase power distribution systems 
had only two phases, again separated by 90 degrees.

Best regards,

-- Bert --
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Tesla list wrote:
>Original poster: dhmccauley-at-spacecatlighting-dot-com
>240VAC is correctly denoted as SPLIT single phase.  It is NOT two phase.
>It is simply a centertapped, 240VAC single phase line from a single phase
>transformer.
 >

>Dan
>
>Two phase denotes a phase angle difference of 180 degrees. The sum of all
>phases in any system must always equal 360 degrees. The standard home
>electrical system in the US is two phase, 180 degree difference( two times
>180 equals 360). Each phase is 125 volts RMS to neutral, and 250 volts RMS
>from phase to phase.
>allan
>
>.