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Re: 50%



At 03:25 PM 11/4/96 +0000, you wrote:
>From MALCOLM-at-directorate.wnp.ac.nzMon Nov  4 06:44:55 1996
>Date: Mon, 4 Nov 1996 19:02:23 +1200
>From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
>To: tesla-at-pupman-dot-com
>Subject: Re: 50%
>
>Jack,
>         I'd like to comment on some of the points made in your post 
>to Bert
>
>> 1. The commonly accepted  limit of 50% transfer (efficiencies?) is for the
>> current and power and not for the energy transfer limitation. This is a
>> common mistake made by many people.
>
>Would you be able to make a clear distinction between the two please? 
>
>> 2. Energy cannot be transferred instantaneously so the amount of transfer
>> time is important and is determined by the coupling. The coupling must be
>> correct for the 100% transfer of energy.
> 
>Agree.
>
>> 3. The coupling does not take part in the energy transfer itself but is
>> important in determining the transfer time. Maximizing K should be to
>> coordinate the transfer time so 100% of the energy is transfered. 
>
>I have a problem with that. Maximizing k (i.e. k approaching 1) 
>certainly allows energy to get across in the quickest possible time. 
>But various values of k (0.6, 0.385, etc the magic numbers) _also_
>ensure that transfer runs to completion. 
>
>> 4. Critical coupling may not give the correct time for 100% energy transfer.
>
>Our coils are overcoupled, period. They all give a double-humped 
>unloaded response. When two circuits are critically coupled, it is 
>axiomatic that an equal amount of power is dissipated in the source 
>and load impedances. 
>
>> 5. Quenching the gap at the appropiate time is important so all of the
>> available energy is transfered. Proper quenching is also important for other
>> reasons not related to enrgy transfer.
>
>Agree
> 
>> 6. To obtain more output (spark length) with maggies compared to classical
>> coils would not require more efficient energy transfer for the primary to
>> secondary coils because it is already at 100%. However, it would require
>> less total loss in the system which appears to be possible. 
>
>Well consider that magnifiers are typically run with a higher k in 
>the pri-sec system than the typical 2-coil jobs. The magic there is 
>fewer gap conductions (=losses) in effecting a complete transfer.
>
>> I have never seen calculations of controlled tests that maggies do
>> produce longer sparls compared to a properly designed and adjusted
>> classical coil.
>
>I think it is possible at higher k's for the reason stated above.
>
>Comments?
>Malcolm
>
--------------------------------------

Malcolm - 

I am not certain I understand some of your questions but I will give it a try.

1. Current can be limited to 50% without limiting energy if the voltage,
etc., changes.

3. When Skilling said "coupling does not take part in the energy transfer"
I think he means that the energy is represented by a certain number of
dampened wave cycles that are controlled by other parameters (Cp, Lp) in the
primary circuit and not by coupling and the transfer is according to
Faraday's induction theory.

4. I agree that Tesla coils are overcoupled and give double humped unloaded
response. However, the distance between the humps varies on a scope
according to the coupling. This does not take a part in the energy transfer
but is a time function (difference in frequencies). This time is independent
of the amount of energy transferred. In other words too much time does not
mean over unity energy would be transferred which we usually assume.

6. I believe that magnifiers may have less loss in the third coil compared
to the secondary coil because it is outside the primary coil influence
(Tesla's Notes) . I have made preliminary tests with a small coil but the
spark length was about the same for both systems. I agree with Richard Hull
that magnifiers are apparently good only for large coils because small coils
are usually very efficient (for air core transformers).

Higher K's would be a factor with magnifiers but are not involved with
losses. The K should be selected for optimun transfer time. I am not certain
how the K factor equations should be optimized. Do you have any information
on this type of optimizing?

Jack C.