Re: TC efficiency, was Math help...

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

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.