Re: IS 240VAC two-phase - NO

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

Original poster: Harvey Norris <harvich-at-yahoo-dot-com> 


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: Ed Phillips <evp-at-pacbell-dot-net>
  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 --
I was quite amazed that quadrature phasing was not
developed. In that system 1.4 amps, (sq rt of 2) sent
out on the delivery line can split into two one amp
currents at the quadrature junction. Thus the shared
phase current lines, or the actual delivery lines have
40% extra current, then exists on the phases
themselves. In contrast with the three phase system it
takes 1.7 amps (sq rt of 3) on the delivery lines to
make two one amp conductions past the delta junction,
so for these cases where it is assumed that the phases
are balanced, the three phase system uses 70% more
current on the delivery lines then exists on the
phases themselves. In the early days of polyphase AC
the losses on the transmission lines became the issue
of the superiority of AC to DC, and here we seem to
have the issue that these losses were further
diminished by going to the polyphase system. If we go
to the phase angle where these  delivery line losses
are minimized to the greatest degree, we find that to
be a 90 degree phase angle. Does this not mean that
the quadrature phasing system has 82%, (1.4/1.7) less
delivery loss then the 3 phase system? If we can show
an advantage here, where is the inherent disadvantage
at? Would it be because 4 delivery lines need to be
used rather then three? More capital expenditure for
the power CO.s infrastructure to deliver power?

Sincerely HDN

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