Re: TESLA COIL REVISED

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

Original poster: jimmy hynes <chunkyboy86-at-yahoo-dot-com> 

Resistance does go up as frequency increases, but a 50 turn coil should 
still have a lower
resistance. The Q may be lower, because the inductance is much lower.

The output voltage of SSTCs has little to do with the unloaded Q, because 
the streamers coming off
totally ruin the Q. It is also much easier to make a 100KHz SSTC driver 
than a 3.5MHz driver.
--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Trans-world" <jaro-at-surfside-dot-net>
 >
 > Gary,
 > and I thought that you are some kind of a Tesla coil expert. What you
 > said doesn't add up. Please see below.
 >
 > -----Original Message-----
 > From: Tesla list <tesla-at-pupman-dot-com>
 > To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
 > Date: Saturday, January 03, 2004 8:02 PM
 > Subject: RE: TESLA COIL REVISED
 >
 >
 >  >Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com>
 >  >
 >  >
 >  >I said no such thing.  A 50-turn secondary would result in a very high
 >  >resonant frequency.  Since AC resistance increases with frequency,
 > such
 >  >a coil would have a higher resistance than one operating at a lower
 >  >frequency.  The lower Q would probably result in inferior performance.
 >
 > NOT SO. Let's compare a 1000-turn 3" diam. thin wire secondary with a
 > 50-turn 12" diam. thick wire secondary. The 1000-turn coil has
 > inductance of about 9 mH, and the 50-turn one has 255 uh inductance.
 > And since that makes the inductance of the 50-turn coil, 35 times
 > LOWER, it will have THE SAME reactance at 3.5 MHz, as the 1000-turn
 > coil has at 100kHz.
 >
 > So you can see that the reactance of the 1000-turn coil is about 5600
 > ohms at 100kHz, and the reactance of the 50-turn coil is ALSO 5600 ohms
 > at its resonant frequency of 3.5 MHz.
 >
 > So what you said is a MYTH. The 50-turn coil resonates at higher
 > frequency, but it WOULD NOT have a higher resistance than one operating
 > at a lower frequency.
 >
 > Now, since the output voltage of CLASSIC TC depends on the L2/L1 ratio
 > instead of a resonant rise, this design wouldn't be good for classic TC
 > because the output voltage would be rather low. BUT, it WOULD be
 > perfect for a SOLID-STATE Tesla coil, because this coil produces
 > RESONANT RISE (as you yourself mentioned).
 >
 > So now that we know that a 50-turn secondary doesn't have higher losses
 > than a 1000-turn one, even though it resonates at much higher frequency
 > (several MHz), we can see that the 50-turn secondary is a superior
 > design when used in SOLID-STATE Tesla Coils.
 >
 > And that's because while the output voltage of 1000-turn coils is
 > limited by the L2/L1 ratio, the 50-turn solid-state TC has no such
 > limitations, and will build up the output voltage to ANY LEVEL that the
 > insulation will allow.
 >
 > Of course the higher frequency will result in shorter sparks, so this
 > coil would be more for people who want to experiment with very high
 > frequencies and perhaps experience beams or walls of light (brush-like
 > discharge), instead of the sparks. And that brush-like discharge would
 > probably be more plasma-like than the usual low-frequency sparks.
 >
 > Jaro
 >
 >  >
 >  >Regards, Gary Lau
 >  >MA, USA
 >  ><snip>
 >  >
 >  >
 >  >---
 >
 >


=====
Jimmy

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