Re: How should we measure coil efficiency
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Wednesday, July 23, 1997 2:00 AM
Subject: Re: How should we measure coil efficiency
Hello John, all,
You said in reply....
> From: FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
> Sent: Tuesday, July 22, 1997 2:58 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: How should we measure coil efficiency
> In a message dated 97-07-22 06:31:59 EDT, you write:
> << Forget the transformer type I say and forget transformer losses
> > in the gap. I know that this makes wallplug figures meaningless but
> > let's face it, they are largely meaningless anyway. If we are to
> > extract any meaningful figure of merit for different coils we simply
> > have to know as accurately as possible just how much power is going
> > into the primary. Failure to do this in the past has led to rules of
> > thumb for power vs length that have been counterclaimed one after the
> > other by actual working coil designs.
> It seems like you're saying that we need to "separate" the different
> parts of our TCs for measurement purposes, otherwise we won't know
> the efficiency of each section...the greater efficiency of let's say the
> power supply in a TC may be compensating for the lower efficiency of
> the RF section in a particular coil...or the opposite may happen in a
> different coil, so we won't know where our efficiency or lack thereof
> actually lies. Well, I agree, we should know which sections of our coils
> are efficient or inefficient and how much...my original suggestion of
> using only power in vs. spark length ignores the question of the
> relative efficiency of various coil sections. But I'm not sure why you
> suggest that transformer losses are unimportant?
Sorry, I didn't mean to convey that impression at all. But I am
suggesting that trying to compare various secondaries for example
(e.g. different inductances for the same Cself) in a performance
comparison would be a lot more meaningful if we knew the primary
power accurately. That means leaving consideration of transformer
losses aside for a moment.
Then we might wish to find out whether secondaries with
different h/d ratios but otherwise identical Lselfs and Cselfs
in the same primary with the same k cause different transformer
losses. What I really mean is that it seems to me that trying to
compare secondaries based purely on wallplug figures will not
necessarily give an accurate comparison. We have to start somewhere
in finding out what influences performance in different parts of the
circuit. I am hoping to do some key experiments in a couple of
months. I have scored use of a decent lab at last.
> Suppose we find
> (for example) that a high break rate makes the RF section of the TC
> more efficient, but makes the power supply less efficient, since this
> affects overall efficiency, don't we want to know about the power supply
> losses? It seems to me that we must monitor the efficiency of each
> TC section. Am I missing some point here?
No, I think you are spot-on. I did convey an erroneous impression.
Wallplug -> primary losses certainly are a major concern. I would
also like to know what the best L/C ratio in the secondary is for
longest sparks, given a particular terminal, Ec, BPS and k. That
might be extremely difficult to determine if the system remains
coupled during spark production (as I suspect it does) in which
case primary L/C figures in the mix as well.
I refuse to believe that we cannot make progress in answering
some of these questions. It is not in my nature to throw my hands up
and walk away from a difficult problem. I am certainly thinking hard
about it while crafting experiments and finding a place to do them.