Re: Single vs Twin TCs

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Original poster: "Nicholas Field by way of Terry Fritz <twftesla-at-qwest-dot-net>" <nick.field-at-hvfx.co.uk>

> Hi list,
>
> A twin TC is alleged to be more efficient than a single TC.  That is, for
> the same power, a twin allegedly can develop a longer streamer between the
> toroids than a single coil can to the air or ground.  Can someone explain
> exactly why?  Is it more than the idea that two smaller diameter primaries

Sure - consider a coil of y power input producing spark x.  John's square
law tells us that to increase the spark length to 2x (assuming the coil can
physically cope with this) with require the power input to increase to 4x.
With a twin you dodge this by producing two sparks, each of length x, which
connect in the middle.  Therefore the power required is only 2y, twice the
efficiency compared to a monopolar coil.

I also have quite a bit of personal empirical evidence for twin's superior
efficiency.  My first twin, built a couple of years ago, hit a max spark of
52" using only a 10kV 50mA neon as power supply.  'Isis' the twin we
developed for rental use manages 8 feet from 2.7kVA input, in conservative
please-don't-break rental setup and about 10 feet from 3.5kVA, in
'overdrive' mode.

Nick

_______________
Nicholas Field
Director,  HVFX
www.hvfx.co.uk