Re: Q Factor and Overall Efficiency

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi John,

	Assuming an arc is 220K ohms plus 1 pF per foot of streamer.  One can make
a little resistor and capaictor to simulate this streamer load.  Simply
connecting a secondary to ground through this load allows one to measure a
secondary systems Q as it is with a load with a signal generator and scope
looking for the center frequency divided by bandwidth method.  Nothing too
dramatic will be found but sort of fun to do...

Cheers,

	Terry
 

At 05:46 PM 8/27/00 -0700, you wrote:
>
>The Q factor tests have been discussed many times in past List posts.
>However, these tests give the Q factor in a low voltage condition. This is
>not the TC operating Q factor. The operating Q factor would give the
>secondary voltage with the equation
>    Vs = Vp * Q
>where Vp is the primary peak voltage.
>
>To find the operating Q factor would require only a scope and the proper
>probe and the knowhow. To do the test find the half power points while the
>Tesla coil is operating. Then determine the Q factor with the equation
>    Q = Fr/(Fh - Fl)
>where Fr is the resonant frequency, Fh is the higher half power frequency,
>and Fl is the lower half power frequency. The Q factor would be the voltage
>gain from the TC input to the TC output. This gain could then be used to
>find the overall efficiency of the TC system. This would be done using the
>energy equation
>     Vs = sqrt(2J/Cs)
>Overall efficiency would be the Vs(half power) test volts divided by the
>Vs(energy) theory volts.
>
>This operating Q factor and TC overall efficiency may be a first in the
>design and engineering of Tesla coils. However, Terry Fritz may have already
>done this? Have other coilers done this?
>
>John Couture
>
>---------------------------
>