In article ,
Randy or Sherry Guttery wrote:

John Byrns wrote:

NO, assuming there is no saturation in the core and the coupling is
perfect the reactance of the two windings connected to "buck" would be
very low and the light would be bright, if they are connected to aid
then the total reactance would be four times the reactance of a single
winding and the light would be dim. When we are talking about "perfect"
coupling we are simply talking about a choke with two windings and
considering what the reactance the two series connected windings would
be with the two possible phasing connections.

Now you've lost me - if there is no saturation - then reactance is max -
regardless of "phasing"... particularly in a three-legged config. (where
coupling is insignificant). The only effect phasing would have would be
symmetrical control - and particularly with an E config. cancellation of
the induced AC field before it combines with (to aid or buck) the
control field.

What am I missing?????

Notice I said "When we are talking about 'perfect' coupling we are
simply talking about a choke with two windings and considering what the
reactance the two series connected windings would be with the two
possible phasing connections." The "perfect" coupling in this example
implies that all three windings are are on the center leg of the core,
and with the primary disconnected we have a simple choke with two equal
windings. Assuming the choke is perfect, the inductance is zero when
the two coils are connected in the series "bucking" configuration, and
is four times the inductance of one winding when they are connected in
series aiding. You can prove this by either measuring a two winding
choke, or by writing the loop voltage equations for both configurations.


Regards,

John Byrns

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