Re: Scott T - Re: IS 240VAC two-phase - NO

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

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 >  >
 >  > Tesla's writings on polyphase waveforms are a classic of beautiful
 >  > exposition and lucidity, and anyone interested in the subject should
 >  > look them up and read them.  That was from Tesla the man, of course.  As
 >  > for Tesla the deity, less said the better on this list.
 >  >
 >  > For anyone who isn't familiar with the scheme, it's possible to go from
 >  > three phase to two phase with a static "Scott T" transformer
 >  > arrangement.  Other transformer schemes can give  six phase, twelve
 >  > phase, etc.  Can't see any reason for TC nuts to be interested.
 >  >
 >  > Ed
 >
 > Does anyone have a design or textbook reference on this sort of thing:
 > Scott-Ts, etc.  I've found a fair amount of qualitative stuff essentially
 > saying what Ed did, but not much on exactly how it's done. I assume that by
 > picking winding ratios correctly, one can sum the I and Q to produce any
 > phase, but, I was looking for  more detail on practical application,
 > particularly with reactive loads.

	Look in any EE handbook.  I just did a Google search and found a lot of
people making transformers but no really good description with a
schematic diagram.  Best was from the URL:

	www.marelco-dot-com/faq.htm#23

Hope I typed that correctly.  It's essentially a system using two tapped
transformers to add up polyphase voltages.  Since the transformers can
be tightly coupled the device is in principle lossless and load
reactance doesn't affect anything.  The analogy to I and Q and
appropriate summing to yield any desired phase is just about perfect if
you remember the process works both ways.

Ed