# Re: How should we measure coil efficiency, was neon vs. potenti

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From: 	John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
Sent: 	Saturday, August 02, 1997 8:50 PM
To: 	Tesla List
Subject: 	Re: How should we measure coil efficiency, was neon vs. potenti

At 09:23 PM 8/2/97 +0000, you wrote:
>
>From: 	Esondrmn-at-aol-dot-com[SMTP:Esondrmn-at-aol-dot-com]
>Sent: 	Friday, August 01, 1997 7:12 AM
>To: 	tesla-at-pupman-dot-com
>Subject: 	Re: TC  Optimum Design -  was ( How should we measure coil
efficiency, was neon vs. potenti
>
>In a message dated 97-08-01 05:51:06 EDT, you write:
>
----------------------------------------------------------    big snip

>John,
>
>You have lost me here somewhere.  Are you saying that for a given secondary
>and toroid combination that is self resonant at frequency x - that there is a
>different frequency for this coil that will be more efficient???
>
>Ed Sonderman
>
>-------------------------------------------------------------------------------

Ed -

The secondary coil and toroid tuned to the resonant frequency is the best
you can do at that operating frequency. The problem is the design frequency
may be wrong for that size of coil. Because all TCs do not operate at the
same frequency there appears to be an optimum frequency for each size of
coil. When the input wattage is larger the frequency is lower and when  the
input wattage is smaller  the frequency is higher. This means there is an
optimum frequency for each wattage input.

At present the operating frequency is determined by the pri and sec
circuits that are made big for large wattage and small for low wattage with
no regard to a possible optimum operating frequency.

A possible equation for the optimum operating frequency is -

KHZ = 3032.5 x W^-.2767 - 96.4       KHZ  = Kilohertz       W =
Watts input

This equation is based on successful coils of the past which may or may
not be ideal.

For example, if your coil is operating with 2000 watts input, the optimum
frequency is 274 KHZ.

If your coil is operating at 150 KHZ the output could be improved if the
frequency is increased to 274 KHZ if no other changes are made. The
frequency could be increased by retuning the primary  and secondary provided
you made the design with enough tuning range.  Also, if your coil is
operating at 350 KHZ and the optimum is 274 the output could be increased if
the frequency is lowered to 274.

You would have to design your coil with sufficient adjustment for a wider
than normal range. The optimum frequency may be the reason that the present
musical toroid  game is being played.

It should also be noted that you would only get more output if your input
source was capable of providing more input. This means that the input
wattage source should be matched to the possible optimum output. There are
several optimizing conditions in the design of TCs that I believe are being
presently ignored.

John Couture

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