RE: FW: Re: Tesla Coil Efficiency Test

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

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


Bart -

The reason the Hi-Voltage Lab, University, and Commercial coilers avoid the
TC efficiency issue is because there is not a good reason for building TC's
like going to the moon so there will not be millions of dollars available
for TC research.

I do not agree that TC efficiency is subjective if tests like the lamp tests
are used. For these tests you only have to be able to read meters correctly
and that can be objective. However, there are a lot of problems when spark
outputs are used and this can be subjective. This is why there is no
agreement on this method amongst coilers. However, there is agreement on the
definition of TC efficiency. It is
      TC eff = energy out/energy in

Why not utilize the TC data we already have available to come up with a
resonable approach to TC efficiency. We can then verify this procedure with
additional testing. Our tests to date indicate that a well designed TC will
give a range of sparks 1 to 40 ft with a 200 watt to 48000 watt input. With
this start we can use this equation.
     Spark output ft = (watt in)^.67/34.8

With these spark outputs we can then find the range of
watts in/ft of spark. This gives us a range of about 200 to 1200 watts/ft of
spark for the 200 to 48000 watts input. With this information we can then
estimate the TC efficiency. We can start with this equation
      TC eff = 7.1/sqrt(watt in/ft spark)

The current in the spark channel increases as the watts input increases and
this equation allows for this current increase. This equation may have to be
changed to agree with new tests.

Note that I do not use bps. The equations above refer to total watts per sec
or energy per second which is needed to find the TC efficiency. Divide the
total watts per second by bps to find the energy in each break. Things like
air density, etc, are not involved with the lamp tests. However, these are
details of the spark tests that would require the spark data to be converted
to standard conditions. These details would probably change the data by
negligible ammounts for our purposes.

Keep in mind that this all comes from test data we have already obtained
except for the estimated efficiency. All we have to do now is to verify the
above by additional tests like the lamp test. The List will then have made
more progress towards finding the TC efficiency than any other person or
organization?

John Couture

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-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, July 02, 2002 6:13 AM
To: tesla-at-pupman-dot-com
Subject: Re: FW: Re: Tesla Coil Efficiency Test


Original poster: "Barton B. Anderson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi John,

I'm not sure that I agree with any of the efficiency thoughts floating
around. My biggest brain block
here are the sheer number of variables. For example looking at watt-sec. If
I increase bps, I increase
my losses during the watt-sec period. Efficiency is dependent on these
types of variables their
interaction. If we were to set parameters to compare by (bps, power,
method, etc..), this still cannot
tell us efficiency outside the window of parameters.

I know I sound pessimistic. I guess I don't realize the usefulness. There
are many coilers who just
love to run at high bps (I'm not one of them). I would guess their losses
are high in comparison over
the watt-sec, but they also switch a lot of power over that same time
period and can take advantage of
streamer and air density relationships. These are all variables that
efficiency tests just can't
recognize.

Efficiency is a very subjective subject, and that in itself is half the
battle. Tesla Coils make
sparks. If we want to design an "efficient" coil as it pertains to spark
length, then we want to
design the greatest spark length for the least amount of input power. That
identifies a comparison of
spark length and input power and will consider all variables involved. If
we want one spark channel or
10, then we need to compare input power to those outputs. I just can't see
any other tests identifying
all the tid-bits, and in the controlled-chaos of coiling, an efficient
design is when experienced
coilers tell their tale and the builder applies the knowledge to their own
set of parameters. Heck, I
would just like to see coilers agree on the what defines effiency.
Typically, spark lengths, but not
always.

Take care,
Bart