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Re: An Interesting Problem
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Monday, October 27, 1997 3:53 PM
To: Tesla List
Subject: Re: An Interesting Problem
Hello John,
Glad you got the oscillograms OK. Thanks again to
Richard.
> From: John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
> Sent: Saturday, October 25, 1997 10:39 PM
> To: Tesla List
> Subject: Re: An Interesting Problem
>
<snip>
> Malcolm -
>
> I have delayed an answer to this post until I received the waveform photos
> that you sent to Richard Hull. Thank you for making these photos available
> to coilers in the USA. I am referring below to photo #3 which Richard said
> was the waveform you used to calculate the transfer efficiency.
>
> The transfer efficiency you refer to cannot be measured as you suggest.
> This transfer of energy from the TC primary coil to the secondary coil is by
> induction and is always a complete transfer (100%). That is the amount of
> electrical energy leaving the primary coil is always completely transferred
> to the secondary coil. None of this energy is lost in the transfer. The only
> factor affecting this TC transfer is the coupling. Reducing the coupling
> will increase the time to transfer the energy from the TC primary coil to
> the secondary coil.
Energy is being lost the whole time in circuit resistances. That is a
given. The longer it takes to effect transfer, the more will be lost
during that period. Also a given.
> However, do not confuse this with the losses that occur independently in
> the primary and secondary coils. These losses cause the reduction of the
> amplitude in the waveform to which you refer. These losses have to do with
> the log decrement, Q factor, and effective resistance (R) in the following
> equations.
Agreed. However, the log dec equeation does not apply to the primary.
Note the linear envelope caused by the non-linear gap (which
incidentally dominates all other losses).
> Q = Xl/R Log Dec = ln(a1/a3) Q = 3.1459 /Log Dec
>
> If the reduction of the waveform amplitude is about 80% as you suggest the
> log dec is .223 and the Q factor is 14. The resistances (R) would depend
> upon the Xl of the primary and secondary coils. A similar example is shown
> in my Tesla Coil Notebook.
Between one secondary peak and the next at the highest amplitude, the
the reduction was a lot less than 80% (around 20% at the most). I
have yet to see a substantive argument that shows my analysis of the
*relative* amounts of energy in the secondary between two successive
beats (at highest amplitude) to be incorrect.
Malcolm
> Also, do not confuse the above with the amount of energy that leaves the
> primary coil. This can be anything from zero to 100%. Regardless of the
> amount of energy in the primary this amount is what is transferred to the
> secondary coil with no losses. In this way the law of conservation of energy
> is satisfied. Many coilers and people working in electronics have trouble
> understanding this interesting application of the energy law. Why is it that
> this cannot be called perpetual motion ?
>
> There is much more to Tesla coil operation.
>
> Comments welcomed.
>
> John Couture
<snip>