RE: The Tabletop Tesla Coil Showdown - OFFICIAL RULES and WEBSITE

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Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


John F. -

Let the contestant use any rep rate he desires. Now that would be a real TC
challenge. Low rep rates would give more spark only up to a certain point.
When that point is reached the losses would start to be greater than the
input and the spark length would remain the same or start to decrease in
length. This happens often with coilers who add input watts to their coil
but beyond a certain point the spark length remains the same length much to
the chagrin of the coiler.

A contest with these rules means that a coiler would have to build dozens of
coils of different configurations and inputs to find the optimum Tesla coil
that would have the greatest spark length percentage over your equation. My
estimate would be that the winner of this type of contest would have a coil
that has less than 1000 watts input. I base this on spark data from the
List. For example many 1000 watt coils give sparks over 4.5 ft, but there
are no coils under 10 KW input giving sparks over 14.2 ft. Larger coils are
even less spark efficient. Note that pole type transformers have an output
capability of over 10 times their nameplate rating when shorted. This means
that the watt input for a certain random spark length would have to be an
instantaneous type wattage. This type of metering is never done for pole
type or similar transformers.

John Couture

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-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Sunday, October 06, 2002 3:55 PM
To: tesla-at-pupman-dot-com
Subject: Re: The Tabletop Tesla Coil Showdown - OFFICIAL RULES and
WEBSITE


Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<FutureT-at-aol-dot-com>

John C,

I would say the opposite is true; that coils become more
efficient at high powers.  A lot more large coils beat my
formula than do small ones.

A 6" spark with 5 watts input?   It must have had a very low
rep rate.  At a low enough rep rate, one could get a 5 foot
spark with 5 watts.

John F.


>
> I agree with Malcolm. Beating John Freau's  1.7 sqrt(VA) is more of a
> challenge to coilers. That is the first rule required. The second rule
would
> cover the type of spark. Spark types have never been agreed upon by
coilers
> in the past for any kind of test. Because large coils are inefficient only
> small coils could be used. I believe it was R. Hull who said that he was
> able to get a 6 inch spark with 5 watts input. That is a 57% increase over
> the John F. equation. So the challenge is not an impossible goal.
>
> As the input VA of the Tesla coil is increased the overall efficiency
> decreases and the maximum spark length becomes much less than the John F.
> equation. It would be interesting to know the VA input that gives the
> optimum spark length. It looks like 5 VA is the winner at present.
>
> John Couture