# How to rise the secondary?

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-----Original Message-----
From: John H. Couture <couturejh-at-worldnet.att-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Date: Wednesday, July 01, 1998 2:58 PM
Subject: How to rise the secondary?

To Ed, Antonio, Bert, and Malcolm -

Many thanks for all the information regarding the raising of the
secondary. It is gratifying to know that with the Internet and Tesla List it
is possible to ask technical questions of this nature and be able to receive
immediate replies from around the world. Coilers of only a few years ago
were at a tremendous disadvantage without this type of resource.

As is typical with TC design, answers to a technical question sometimes
brings up more questions.

1. Doesn't changing the coupling (K) only change the time of energy
transfer for a tuned TC system regardless of frequency? For example with K =
.20 the energy will transfer for all coils and operating frequency:
Transfer time = 1/K = 1/.20 = 5 half cycles.

2. The total amount of energy transferred will occur when the TC system is
in tune.
That is when  LpCp = LsCs
What are the equations relating the amount of energy transferred to
special coupling coefficients?

3. If the primary is designed with enough clearance to prevent sparkovers
between the pri and sec coils, raising the secondary would be unnecessary?
In other words the coupling is determined only by the sparkover clearance
limitation. Using insulation instead of air to separate the pri/sec coils
could be used to reduce the clearance and increase the coupling. But this
would not change the amount of energy transfer or the length of sec term
spark.

4. What are the equations relating the quenching characteristics to
coupling and output spark lengths?

5. In #1 above the number of half cycles required to transfer all of the
energy of a tuned TC from pri to sec coils can be found. However, how many
half cycles are required to properly charge a suitable sec terminal so there
will be a sec output spark and quenching time is not important?

6. The point of over/under coupling (critical coupling) is determined when
Rp = Rs  How are these two parameters calculated at the time of
design?
The equation  R = Xl/Q   cannot be solved because both  R and Q  at
high voltage operation are unknowns at time of design.

John Couture

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