Re: HF sparks
From: Peter Electric[SMTP:elekessy-at-macquarie.matra-dot-com.au]
Reply To: elekessy-at-macquarie.matra-dot-com.au
Sent: Thursday, July 31, 1997 7:18 AM
To: Tesla List
Subject: Re: HF sparks
Tesla List wrote:
> From: richard hull[SMTP:rhull-at-richmond.infi-dot-net]
> Sent: Wednesday, July 30, 1997 8:30 PM
> To: tesla-at-pupman-dot-com
> Subject: HF sparks
> High frequency systems just typically have worse sparks due to a number of
> 1. dielectric losses are higher at high frequency
> 2. Coronal losses appear higher
> 3. small capacitors in HF systems mean lower power and less brilliance in
> any sparks thus produced.
> 4. smaller capacities in the terminals limit spark length and color
> It is hard to conceive of a 2 mhz coil system spouting 5 foot white hot arcs
> using normal Telsa coil construction methods.
> In general, most coils under 500 khz are in the toilet spark wise due to a
> any or all of the above reasons.
> I think the argument offered about the higher frequency, higher energy
> between 500khz and say 2mhz is just not a real item of concern where real
> sparks are made and show just how fine hairs are being split on non-issues.
> Richard Hull, TCBOR
>From my own observations so far and from other peoples posts I am
inclined to agree with all of your points except number 3. In the past,
folk seemed to have built Tc's using the clasic formula for Capacitance
vs input power and these have have been good performers. Recently
though, Bert pool and others seem to have been using relatively small
caps with higher break rates and getting very impressive results.
Maybe not quite in the same league but I have recently re-fitted my 3
1/2" 15KV 60Ma TC with a .01uF cap after blowing up my .015uF earlier.
After re-tuning the primary, the forced air gap seems to fire faster but
the length or appearance of the sparks seems to be the same (about 30"
with my present 20" by 8" toroid).
I am about to wind a new 6" secondary and I intend to leave all other
parameters the same so it will be interesting to see if the lower freq.
produces a longer spark?
Cheers, Peter E.