Re: Math help...

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

Original poster: "Brent Turner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bturner-at-apc-dot-net>

John -

Then where does the energy used up in eddy current losses in
transformers (magnetic circuits) come from??? When I hook my 5KVa
isolation transformer up and not pull any load on the other side, the
core does still get slightly warm after a while -- heat indicates
energy, in this case a loss.

- brent



Tesla list wrote:
> 
> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-worldnet.att-dot-net>
> 
> Bert -
> 
> I agree with your excellent comments below, however, I believe it should be
> pointed out that the energy transfer in all magnetic circuits is 100%
> because there are no losses in magnetic circuits. Electric losses are only
> in electric circuits and the efficiency is the ratio of output/input. This
> means that when reffering to electrical efficiency the input and output
> calcs should be shown. This can be a difficult task when talking about Tesla
> coils.
> 
> I understand the voltage can be used to find the joules (energy) in the
> primary capacitor but how do you determine the energy in the secondary
> circuit when the secondary voltage of an operating TC is an unknown? I
> avoided this problem by using a light bulb for the secondary load in my
> test.
> 
> 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
> 
> ----------------------------
> 
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Sunday, July 08, 2001 9:02 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Math help...
> 
> Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <bert.hickman-at-aquila-dot-net>
> 
> Josh and all,
> 
> That's an excellent question, Josh - and it goes to show that very few
> things are truly simple in coiling... :^)
> 
> Malcolm is correct. Previous experiments have measured primary tank
> capacitor voltage during a complete primary-secondary-primary energy
> transfer cycle. These have shown that the efficiency of the first
> primary-to-secondary transfer (from an initially charged tank capacitor to
> a fully resonating secondary) can indeed exceed 90%. However, this makes no
> statement regarding how efficiently we were able to charge the tank cap
> from the mains supply in the first place. For that, we need to talk a bit
> more about capacitor charging circuits...
> 
> -------------------   snip