Re: NST power rating [non] con

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

Original poster: davep <davep-at-quik-dot-com> 


>  > I don't believe this is a verification of the
>  > maximum power transfer
>  > principle. The tests indicate that the maximum power
>  > available from a NST is
>  > only about one quarter not one half of the nameplate
>  > rating.

         Nameplate ratings must fir on the nameplate.
         Sometimes, they have nonobvious meanings, which
         will be found in the manual/data sheet/ or 'craft
         knowledge' for the intended application.

>I was not arguing the point that the transformer
>should deliver its stated short circuit amperage ALSO
>AT its stated voltage rating.  To me this sounds
>nonsensible.  A 24 inch neon placed across my 15,000
>volt rated NST will only show about 500-600 volts
>across it,

         That's the nature of neon lamps.

>and also at less then the short circuit
>current rating.

         Current drawn depends on load, among other
         things.  If the lamp doesn't draw it, that's to
         do with the lamp..


>You had stated;
>The maximum secondary watts output  was 59.3 watts,
>3900  volts, 15.2 ma.
>  >From this comment I had deduced that you tried a
>variety of combinations, and it was this one that gave
>the best results. It was from that standpoint that I
>made the comment that this sounds like the principle
>of maximum power transfer.
>Here is some background info on the principle;
>I will cite from Herbert W Jackson's Introduction to
>Electric Circuits.(3rd edition) I have found his
>descriptions very consise, and here he gives 4
>statements concerning the matter of how internal
>resistance of a stator emf influences the conductions
>on the load.

>1. Maximum power output (into the load) occurs when
>R(L) = R(int)
>Also when R(L) is selected for maximum load power
>I = 1/2 I (short circuit current)
>V(L) = 1/2 E (open circuit voltage)
>This is also 1/2 maximum efficiency
>Note that maximum power output does NOT coincide with
>maximum efficiency. When a load resistance is selected
>for maximum power input, there is an equal power
>dissipation inside the source of emf.

>2. If we want to increase the efficiency, a load
>resistance of from two to three times the internal
>resistance of the generator results in appreciable
>reduction in wasted power ( as heat in the generator)
>for only a small reduction in power output.

>3. A load resistance less than the internal resistance
>of the generator not only results in a reduction of
>power output, but also causes a very high dissipation
>within the generator. In practice, this condition of
>operation is termed OVERLOAD and must be avoided.

>4. If we are interested more in voltage output than
>power output (as in transistor and vacuum-tube
>amplifiers), the load resistance should be high in
>comparsion to the internal resistance of the source
>of emf.

>What I was doing here was to simply compare the NST
>secondary as if it were a generator source of emf.
>This may be a mistaken approach, but it seems apt.
         NSTs are designed to include current limiting,

         internally.

         'power transformers' are designed for max power
         out/maximum efficiency.
         NST's are designed to match the specific, negative
         resistance, characteristic of a gas discharge ('neon')
         lamp, and to protect that lamp by not over currenting it.

         best
         dwp

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