Re: Single vs Two Phase (was - Spark gap erosion resistance)

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Clearspring1-at-aol-dot-com>

Terry,

A lucid explanation, and I thank you.

Regards,

Michael Tandy

> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>  
>  Hi Michael,
>  
>  The reason for the "controversy" is that the true electrical engineering
>  definition says that the number of phases is related to the armature
>  construction of an alternator.  One winding gives single phase AC.  It
>  "does not matter if you take the center as ground", it is still single 
phase.
>   
>  
>  Two windings give two phases at 90 degrees (pictures are more clear) and
>  three windings give three phase at 120 degrees apart.  It goes on for four,
>  and six for "odd" machines...  The 120 VAC in our houses is actually 1/2 of
>  a single phase (one side is neutral).  The 240 VAC for the oven and dryer
>  just uses the full phase.  Of course, this one phase to our houses is just
>  one leg of the original three phases from the "alternating plant" (in this
>  case, we won't give Edison the pleasure of referring to it is a generating
>  plant which is "supposed" to imply DC :-)))
>  
>  If you were to really look hard, you would see that the common 120VAC in
>  homes actually has six variations around town that are 60 degrees apart.
>  This is done with the three phase transformers, pole transformers, and
>  grounding to split it all up.  However, it is not uncommon to refer to the
>  two 120VAC components to the house as phases even though it is not
>  technically correct.  That's what "I" did that got this mess started =:-O
>  
>  If one figures all this out and adds in the delta and wye configurations,
>  you have "arrived"...  But for those that just see the wires and think they
>  are all "phases", "I" will "understand" and forgive them for not getting
>  into the messy details.  *:o)  We won't even touch the folks that refer to
>  the "neutral phase" and "ground phase" :o)))
>  
>  If one takes the output of a three phase alternator and thinks off ALL the
>  ways to hook transformers and grounds together, you will see how complex it
>  can get.  EVERY one of those variations is in common use...  That's why we
>  have electricians and/or engineers to figure it all out for us.  ;-))  
>  
>  This is what happens to something "simple" after engineers have 100 years
>  to work on it :o)))
>  
>  Cheers,
>  
>   Terry
>   
>