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RE: TC efficiency, was Math help...



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


John F. -

With a small coil the input watts would be about 200 watts per foot of
spark. A larger coil would require more than 200 watts for the same length
of spark. This means the losses are greater and more watts are required for
the larger coil. The efficiency is, therefore, less for the larger coil. The
greater losses for the larger coil is usually in the spark gap and corona.

I agree a loose coupling will appear to increase losses but note that there
are no equations to relate coupling with efficiency.

John Couture

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


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Monday, July 16, 2001 10:16 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 7/16/01 9:49:40 AM Eastern Daylight Time,
tesla-at-pupman-dot-com
writes:

> 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.

John,

The first sentence above is correct, the second is not, in my
opinion, because the the second sentence is not a correct
logical result following from the first sentence.

>  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 often see a lot less corona on a large coil.  In any case, Tesla
made plenty of mistakes, even though he was a genius and a good guy.
>
>  Note that coupling is not involved with efficiency, only with the
>  Coefficient of Leakage which is an interesting magnetic circuit
limitation
>  for Tesla coils.

Coupling is indeed involved with efficiency, but indirectly.  If the
coupling is too low, the energy stays in the primary too long, and
gap and primary losses increase.

>
>  I agree we have a lot to learn about Tesla coils before we can design
them
>  with a minimum of guestimating.

I can a agree with that.

JOhn Freau
--
>
>  John Couture