Re: Coiling myths

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>



A great post with valuable information.  Keep thinking Paul!

Dr. Resonance




> Original poster: Paul Nicholson <paul@xxxxxxxxxxxxxxxxxxx>
>
> While I'm in the mood for summarising things, I thought I'd list
> some of the theoretical myths that seem to keep cropping up in
> Tesla coiling:-
>
> * Myth: Signals travel through a coil as if they were moving at
>          light speed through the wire.
>
> (They don't.  The effective velocity 'along the wire' of a solenoid
>   is given to within a few percent by ln(h/d)*0.39 + 1.19 times c.)
>
> * Myth: Lumped operation is a different thing from distributed
>          operation.
>
> (These are just two levels of detail in the mathematical modelling
>   of coil resonance.)
>
> * Myth: Voltage magnification is much higher than the turns ratio
>          of secondary to primary, attributed to 'resonant rise'.
>
> (The voltage ratio is rather less than the turns ratio due to the
>   limited coupling between the two coils.)
>
> * Myth: Current in the wire offers a different mechanism for energy
>          transfer to the E and H fields.
>
> (It doesn't.  Fields and currents are bound together, and a given
>   energy flow (along a coil, say) can be described equivalently
>   using either set of terms.)
>
> * Myth: The low frequency inductance, Ldc, as measured by an LCR
>          meter or estimated by Wheeler, is the effective resonating
>          inductance.
>
> (It isn't. It doesn't correctly represent either the stored energy or
>   the ratio of top volts to base current, because it doesn't allow for
>   the non-uniform current.)
>
> * Myth: The bulk capacitance of the coil, Cdc, (measured at uniform
>          voltage by an LCR meter) is the effective resonating
>          capacitance.
>
> (It isn't.  It has the same defects as Ldc because it doesn't allow
>   for the non-uniform voltage in the resonating coil.)
>
> * Myth: High Q factor is important for secondary coils fired from an
>          initial charged primary cap.
>
> (Only a modest Q is required.  Output voltage is not proportional to
>   Q as some suggest, but is limited by energy conservation.)
>
> I've only listed the myths that I feel confident to discuss and
> refute.  Perhaps others can add to the list from their fields of
> expertise?  Let's not bother with the numerous myths about
> Tesla Himself, nor the inane core beliefs of the many modern techno-
> superstitions.
> --
> Paul Nicholson
> --
>
>
>
>