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>


John F -

A well known characteristic of Tesla coils is that the watts per foot of
spark increases as the TC gets larger. This means losses increase and
efficiency decreases as the TC is made larger. The range is about 200 watts
per foot of spark for small coils to 2000 watts for large coils. This is
based on measurements that  coilers make every day. Have you made
measurements that would indicate the contrary?

John Couture

---------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, July 11, 2001 6:35 AM
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>"
<FutureT-at-aol-dot-com>

In a message dated 7/10/01 9:08:09 PM Eastern Daylight Time,
tesla-at-pupman-dot-com
writes:

> >
>  >When we say the TC efficiency can be about 90/95% what are the input and
>  >output conditions? Coilers talk about TC efficiencies but I have never
seen
>  >any published input/output calcs. In my TC Construction Guide page 14-4
I
>  >show a simple efficiency test I made with a small TC and the
input/output
>  >calcs were shown. Have any other coilers made these tests? The test
showed
>  >an overall efficiency of 56%. Larger coils have efficiencies much lower.
>  >What are the input and output calcs for the 90 to 95% efficiencies? How
do
>  >they relate to the overall efficiency? How do these 90/95% efficiencies
> vary
>  >with TC size?
>  >
>  >John Couture

John, all,

The 90 -95% figure is only for energy transfer from primary
to secondary for first notch quenching, not for overall TC efficiency.
Many coils quench on the 3rd notch, so the transfer efficiency may
be around 65% in that case.

Charging efficiency is often around 85% or so, and there's some
loss in the secondary.  This brings the overall efficiency down
to perhaps 50% for the overall TC for input vs output.  This is
ballpark.

This issue of efficiency for small vs. large coils has been discussed
previously on this list.  I would say that large coils are more
efficient than small ones, mainly because various transformer
% losses are lower in larger transformers.

John Freau