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[Amps] My new Toy. Off Topic & Zippers. Final.

To: <amps@contesting.com>
Subject: [Amps] My new Toy. Off Topic & Zippers. Final.
From: W8JI@contesting.com (Tom Rauch)
Date: Thu, 11 Jul 2002 06:06:58 -0400
Hi Alex,

> I will remind you for the "n" th. time that these words have been used
> as a comparative point for those that do not understand the process of
> nullifying a reactance with one with an opposite sign.
> 
> To be more concise and to clarify this issue once and for all:
> 
> Any device, including a power transformer has a definite and
> measurable reactance at it's operating frequency. In the case of an
> 220VAC transformer this reactance has two components, one inductive -
> from the winding it self - and one capacitative created form the
> internal inter-thread and coil to core capacitance. All losses in a
> transformer, including leakage, are related to these rectances. A good
> engineer will always attempt to reduce them as it ultimately
> translates in heat.


That's where you are incorrect Alex. You are confusing power factor 
correction or resonance with conjugate matching. They are two very 
different things!!

To achieve resonance or correct power factor, we simply add a 
reactance of the opposite sign either in series or in parallel with 
the system reactance. This brings voltage and current into phase, and 
corrects any VAR power problems outside the resonant system.

The equation involves only -j and +j terms.   
That is what you incorrectly are calling "conjugate match".
   
Conjugate matching by definition includes an R term. A conjugate 
match is when R+jx is complemented with an equal but opposite R-jx.

If you conjugately matched a power supply to the power mains, as you 
claim, current would be phenomenal! That is because the source 
resistance of the power mains is VERY very low.

We do conjugately match antenna systems, and can use matching stubs 
to insure a conjugate match, but that is only because we are dealing 
with power limited sources that have a lot of dissipative or non-
dissipative source resistance. I'm afraid if someone conjugately 
matched a power transformer to the power lines, they would blow the 
breakers or start a large fire.

If you look at any engineering text, you will see conjugately 
matching always involves R and X terms, while the effect you call 
conjugate matching is actually just resonance or power factor correct 
at best.

73, Tom W8JI
W8JI@contesting.com 


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