RE: TC efficiency, was Math help...

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

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


Matt -

How would you measure the efficiency of a Tesla coil?

John Couture

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-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, July 18, 2001 12:02 PM
To: tesla-at-pupman-dot-com
Subject: Re: TC efficiency, was Math help...


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

Hi All,

> The input power for a foot of spark always is larger for larger coils
> compared to small coils. This is an indication that larger Tesla coils are
> less efficient than small coils. I think Tesla mentioned this in the CS
> Notes. The reason is that large coils have much heigher voltages than
small
> coils and this increases the corona, etc, losses per unit of output/input.

        I think that part of the "efficiency problem" is the careless misuse
of terms. Efficiency is a dimensionless number. Therefore any legitimate use
of the term MUST have the same units on both sides of the equation (e.g.,
power in/power out,
energy in/energy out, etc.) feet per kW cannot therefore be a measure of
efficiency. It is a measure of something else which may be desirable.
        Another thing that seems to be totally overlooked is that a Tesla
coil is NOT a one dimensional object. It operates by influencing the
contents
of a VOLUME of space. The volume of air ionized is a D^3 phenomenon. Effects
at a certain distance are surface AREA phenomena, i.e., D^2. Extrapolating a
sqrt measure like length per watt quickly shows that the most efficient
Tesla
coils are those with zero output and zero input since limit(dl/dw)=1 only as
w tends to zero. Trying to define efficiency in terms of a linear measure is
therefore silly^2 or silly^3.
        (This implies that the power/streamer length relationship may be a
fractal with Hausdorff dimension between 2 and 3.)

Matt D.