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RE: NST power rating con



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


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "John H. Couture"
 > <couturejh-at-mgte-dot-com>
 >
 >
 > Tom -
 >
 > There is only one test to find the maximum watts
 > output of your NST. You
 > need a HV voltmeter, ma meter, and a bunch of
 > "power" resistors. Then make a
 > graph of output watts vs the resistive load. I did
 > this with a 7500 V, 30
 > ma, 225 watt NST. The maximum secondary watts output
 > was 59.3 watts, 3900
 > volts, 15.2 ma. The input was 120 volts, 1.45 amps,
 > 174 VA, 60 watts, 34.5%
 > PF. The NST overall efficiency was 98.8% at maximum
 > output!! The efficiency
 > drops to 22% with an 8.0 Kohms load.
 >
 >     Overall efficiency % = 59.3/60 = 98.8%
This sounds like a verification of the maximum power
transfer principle, which occurs when R(int) = R
(load)
When this occurs the voltage that developes across the
load will be ~ half the voltage found at open circuit.
(3900 volts with load vs 7500 volts open circuit)
Since a shorted NST represents only R(int) as that
load, if R(load) = R (int): this is twice the
impedance, (or more properly resistance), on the total
current loop, so we should expect ~ half of the
measured short circuit current to exist.
( 15 .2 ma loaded current vs 30 ma short circuit
current)

Problematic with these definitions is how we define
R(int). Things seem to make sense if we define it as
the inherent impedance of the secondary, not merely
its resistance. The limitations involved with
ferromagnetic resonance are also shown by giving the
secondary an equal capacitive reactance to R(int)'s
reactance. A current equal to what would develope by
ohms law never actually developes, and what does
develope is only a small % of that value. Applying the
same "maximum power transfer" principle to just
reactances would mean that perhaps we should only
expect HALF the current that would be found with ohms
law to develope. I doubt if it even goes close to
that. The limitations of what a "resonance" should
yeild by book value calculations as an "ideal"
component vs what it delivers as a "real" component
seems to be quite a vast difference. A 1000 ohm
multiturn 60 henry air core coil put into 60 hz
resonanace only delivers 75-80% of its possible
resonance. The same coil placed with 480 hz alternator
inputs only delivers 5% of its possible resonance.
This figure can be doubled  to 10% by allowing another
magnetic field to exist in magnetic opposition to that
coil. It is thought that internal capacity brought on
by interwinding capacity is the culprit that limits
the available amount of resonance. This also seems
comparable since at 8 times the frequency, the
limitations have been increased 8 fold for the best
possible resonance obtainable for the input
conditions.
 >
 > Many other tests (1980's) gave surprising results.
 > With certain combination
 > loads of resistors and capacitors it was possible to
 > make graphs with VA
 > output greater than VA input!
This happens to a great degree with certain alternator
source frequency air core transformer resonant
circuits. An ending load can have 10 times the
resistance vs what is inputed as a primary input, and
on the secondary side a 10 fold voltage rise can be
obtained. With ordinary transformer principles we
might expect an accompanying 10 fold reduction from
the secondary currents, since the output voltage has
risen 10 fold. Yet we can obtain the same amount of
current on the secondary ending circuit as that
inputed to the primary. The VA input vs VA output has
increased 10 fold, even with the the loads having a 10
fold difference in resistance!

HDN