Re: curious TC questions on Freq. limits

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

Tesla list wrote:

> Original poster: "Jan Wagner by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jwagner-at-cc.hut.fi>
> Hi,
> On Tue, 8 Oct 2002, Tesla list wrote:
>>Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <CoolCorals-at-aol-dot-com>
>>Hello, I have been curious about a few things with a tesla coil.
>>First:  I have read some of tesla's patents and articles.  It seems
>>Tesla talks of a TC running in the MHZ to 100MHZ ranges, has anyone done
>>this?

	One of the Professor Corum's grad (?) students
	built something very like a Tesla Coil at 160
	MHz, with a simple 1/4 wave vertical.  Operated CW
	it had 'plasma flames' off the top end.

>>  Is it possible?
	sure.

	Useful/practical may not be the same question.


> There's a project paper around in which a group made a 5 MHz TC.
> Naturally, at 5MHz the coil size is tiny, it is prone to detuning
> (just thinking about driving it with a 5 MHz signal generator), and input
> power has to be quite small to prevent this small TC from burning up.
> Energy "losses" are high.

>>     Second:  It seems that tesla often used DC for the input to his TC's,
>>and the rotated a "contactor" to determine input frequency.  How does raising
>>or lowering the input frequency from 60 hz change the resonant frequency?

> Doesn't affect it at all. The resonant frequency/ies of neither the tank
> nor the TC secondary depend on what exactly you use to feed the TC.

> But, changing the contactor speed (rotational spark gap?), you will change
> the energy per bang. That depends on the supply VA rating and frequency,
> and how you charge, and what kind of supply it is (DC, AC, 3-phase).
> 
> Someone else on the list will probably know better what Tesla tried to do
> with DC and the rotated contactor... :-) My guess is that he was just
> determining the optimum time (i.e. bps) to fire the gap/close the
> contactor, which is after the tank cap has been fully charged up to DC
> supply voltage. Something like T_charging >= Z_out_supply * C_tank, or so

	Tesla worked with a variety of configurations, over 10-20
	years, testing a variety of configurations...

-- 
	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me