Re: Explain 3 Phase

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

Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>




>	(on the 'phase' of the 110/240v:
>		This seems to ALWAYS lead to confusion, usually
>		due to semantics, rather than facts.
>
>		FACT:
>			The two legs are in phase.
>			(think about it:  If they were not, there
>			would be 0v, not 220v, across the outside...

then why is it that in Op-Amps they use the term "common mode rejection"
to refer to the "[difference from the expected] zero output voltage" from
two inputs that are "common" IE "have the same phase" IE "in phase". 

We coilers also use "in phase" to refer to two (or more) NSTs connected
in parallel such that the voltage between outputs of any two of them is ZERO
(not the two output terminals of one NST, rather two output terminals of
different NSTs that you are about to tie together to parallel the NSTs). 

You seem to have it backwards from the common use of the term "in phase".

What the two legs have in common is 60-Hz, other than that they are 180-
degrees out of phase. I think you are confusing frequency with phase.


>
>		Commonly it is said they are 'out of phase', this results,
>		usually, from hooking a scope up ab looking.  Scope doesn't
>		lie, right?
>		BUT:
>		It IS connected to a center point.  This MAKES ends
>		LOOK OUT OF PHASE.  It's an artifact of the hookup...
>	
>		If 4 probes, & four channels, are available, set up two
>		differential channels, taking due care of which channels
>		are inverting....
>
>	best
>	dwp

Peter Lawrence.