Re: FW: Re: Tesla Coil Efficiency Test

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

Original poster: "D.C. Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <DR.RESONANCE-at-next-wave-dot-net>


You could take a good storage scope "snapshot" of the secondary ringing and
then use differential calculus techniques to find the total stored energy in
the sec. circuit.  Using this same technique for the pri. will give you the
total actual stored energy in the pri. circuit.  From this data you can
calculate efficiency.

I never said it would be "easy".

Best regards,

Dr. Resonance

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, July 06, 2002 1:00 PM
Subject: RE: FW: Re: Tesla Coil Efficiency Test


> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
>
>
> Paul -
>
> How the loss of energy is determined when the energy is transfered between
> the secondary coil and the lamp is a problem that will have to be solved
for
> this test. One possible test is to use the coupling test I show in the TC
> Construction Guide. The coupling factor is found by
>         K = sqrt(1-(Fo/Fs))
>
> With the pickup coil wire wound tightly around the bottom of the secondary
> coil the coupling would be high, something like 0.6 or higher. The wattage
> output found by the lamp test could then be divided by this coupling
giving
> a new larger wattage output. This could give the true overall TC
efficiency.
> However, this would be a secondary coil to load loss only for a particular
> type of lamp load.
>
> The problem that you mentioned regarding how the lamp load can be made to
> represent the streamer load may be even more difficult to resolve. How do
> you make a continuous constant electrical load represent an intermittent
> spark load? For example at 120 BPS does dividing the total watts of the
lamp
> load by 120 to represent a spark output make sense?
>
> There is still another problem that will have to be solved. How to find
the
> optimum test lamp voltage and wattage as the Tesla coil becomes larger. I
> tried to estimate this voltage and wattage in my original meager research
> but things got complicated and I ran out of time. In general I found the
> larger the TC the higher the lamp voltage and wattage that was needed.
>
> I agree it appears that we can define a measurable "efficiency" of a TC
> provided we make clear what type of output we are using, such as lamp
> output, spark discharge, ringdown, etc.
>
> John Couture
>
> -------------------------------
>
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Friday, July 05, 2002 11:48 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: FW: Re: Tesla Coil Efficiency Test
>
>
> Original poster: "Paul Nicholson by way of Terry Fritz
<twftesla-at-qwest-dot-net>"
> <paul-at-abelian.demon.co.uk>
>
> John Couture wrote:
>
> > Keep in mind that the lamp test is not dependent on the
> > charateristics of the lamp.
>
> It's appreciated that the single level comparison avoids
> calibration or linearity issues.
>
> However, the problem with the lamp test is that the number it
> produces refers to the efficiency of energy transfer to that
> particular lamp with that particular degree of coupling to the
> secondary coil.
>
> If you run the test with the lamp fairly loosely coupled to
> the coil, you'll get a smaller value for the apparent efficiency
> than you would if the lamp was coupled more tightly.
>
> For the lamp test to be a viable method for assessing the
> efficiency of the coil when operating into a streamer loading,
> then somehow you will have to adjust the coupling of the lamp
> so that it dissipates the same fraction of stored energy per
> cycle (on average) as does the streamer load during operation.
>
> > Malcolm's transfer method for finding the TC efficiency does
> > have merit.  However, it must be understood that this represents
> > only the efficiency of a part of the TC system and some losses
> > sre left out.
>
> Yes, I agree. We only get the efficiency of the RF parts of the
> system by using methods based on ringdown.  Losses in supply
> transformers, ballasts, PFC, etc are invisible.  The lamp test
> does give an overall efficiency, rather than just an RF efficiency.
>
> I don't see any fundamental problem with defining a measurable
> 'efficiency' of a TC, providing you are clear on what you consider
> the 'output' to be.  For example, if you choose the streamers to
> be the output (as opposed to spark discharges to ground, or energy
> coupled to a receiver coil), then by measuring the ringdown times
> at just above and just below breakout, and treating these as loaded
> and unloaded Q factors respectively, the RF efficiency can be
> calculated in the normal way just as you would for any other tank
> circuit.  As another example, if you were wanting to transfer
> power to a wireless load, for example an inductively coupled lamp,
> then you would measure the ringdown times with and without the
> lamp circuit closed to obtain the RF efficiency of coupling to the
> lamp.   Similarly for other loads which give a meaningful
> average decay rate to the stored energy.  Spark discharges to
> earth don't meet this qualification and a modification to the
> ringdown test is required for this, but the RF efficiency is still
> obtainable.
>
> > The decay rate of the secondary base current sounds interesting.
> > How would you do the metering to find the energies?
>
> The RF efficiency obtained by ringdown tests must be qualified by
> an input power measurement, the BPS, and either a firing voltage or
> a peak primary current measurement in order to obtain the energies
> and an overall efficiency figure
>
> All in all, the lamp test would be a much simpler and more
> accessible method, if some way could be found to ensure that the
> lamp loaded the resonator down to the same Q (and same Fres for
> that matter) as the operational streamer load (or some other
> definition of output) does.
> --
> Paul Nicholson
> --
>
>
>
>
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