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Who or what is Q [Length to Dia ratio]
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From: D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Sunday, August 23, 1998 9:48 AM
To: Tesla List
Subject: Re: Who or what is Q
to: Reinhard
While it is true that pi seems to be the optimum value for efficient energy
transfer and potential production, this value falls short of good design
criteria when the flashover potential of the secondary is considered. With
modern design parameters producing arc discharges of 2-3X the sec coil
length, this pi value ratio, if used, will only produce headaches and
burned sec coils. We have long ago standardized our commercial units to a
value of 4.5:1 and 5:1 which seems to be the optimum blend for both
potential generation and flashover protection. Consider 4.5:1 for all
small to medium coils and 5:1 for units running over 10 kva and you will
produce powerful discharges with minimum flashover problems. We have used
these design parameters in units producing spark lengths up to 76 ft
without additional problems. Our "Big Bruiser" which was displayed at our
fall open house last year uses a 5:1 ratio.
DR.RESONANCE-at-next-wave-dot-net
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From: Tesla List <tesla-at-pupman-dot-com>
To: 'Tesla List' <tesla-at-pupman-dot-com>
Subject: Who or what is Q
Date: Saturday, August 22, 1998 9:55 PM
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From: W Y Liu [SMTP:eenwyl-at-sun.leeds.ac.uk]
Sent: Saturday, August 22, 1998 10:06 PM
To: tesla-at-pupman-dot-com
Subject: Re: Who or what is Q
Given that there is an oscillator of Q=100, the time constant
of the turn-on transient for this oscillator is roughly 100
cycles of the oscillation frequency in length.
Louis
(non-coiler)
> From tesla-request-at-pupman-dot-com Sat Aug 22 22:40 BST 1998
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> Subject: Who or what is Q
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> ----------
> From: RWB355-at-aol-dot-com [SMTP:RWB355-at-aol-dot-com]
> Sent: Saturday, August 22, 1998 12:41 PM
> To: fwd
> Subject: Who or what is Q
>
> Hi all,
>
> There has been a lot of talk about "Q". Let me see if I can shed some
light on
> who or what Q is.
> NO Q isnīt that dude from Star Trek.
> Q is a ratio factor that describes the behavior of a circuit. Without
running
> a lot of math:
>
> w(omega) * L
> Q= ------------------ Lets simplify this as w=2* pi*F
> R.
> 2*pi*f*L
> = ------------------
> R
>
> So this means Q is the ratio of inductive reactance to (ohmical)
resistance.
> The higer your Q is (Read: high inductive part, low resistance part) the
> "sharper" your resonance curve is (if you plot it). A small Q (e.g.=1)
would
> give you a lazy curve like an upside down "U". A high Q (e.g. 1000) on
the
> other hand would give you a fast rise / fast drop curve with a real
needle
> point as the peak value. The "cut-off", if you will, is much harder.
Taking
> this and the transformer laws into account you can now see why a high Q
coil
> will be able to produce a longer and fatter spark. This also shows why
you
> canīt (like I first did, growl!!) just go to wire length calculations
for
your
> secondary. A small coil (high h/d ratio) will have a different
inductance
than
> a big coil (low h/d ratio) wound with the same length of wire. The big
coil
> (using thicker wire) has a better Q, so it will perform better. Of
course you
> need to adjust the input power for the bigger coil. The bigger coil will
need
> more juice. But if you connect your big ps to the smaller coil you will
get
> less output bang for your money. What I find very intersting is that the
> optimal h/d ratio turns out to be Pi (3.14159 etc), but it does make
sense if
> you look at several ac equations.
>
> coiler greetings,
> Reinhard
>
>
>
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