Re: Re Basics
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Sunday, August 03, 1997 3:59 PM
Subject: Re: Re Basics
A few comments:
> From: Julian Green[SMTP:julian-at-kbss.bt.co.uk]
> Sent: Friday, August 01, 1997 11:56 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: Basics
> >Greetings from Australia! I have been "lurking" in the background for a while
> >and I must say this is a GREAT list! Very informative, but a fair bit is
> >rather advanced for me at this stage, as I have yet to build my 1st Tesla coil.
> >Would appreciate it if someone good guide me on where to start in the midst
> >of all this excecellent technical information. I guess I should start on
> >something of lower voltage and ease of construction 1st.
> >Then advance to the "power user" class later! :-)
> Starting on lower voltages is slightly safer but by not much. Getting a zap
> from a charged 0.02uF capacitor at 8KV could to be fatal. Make sure you
> discharge your caps before you make adjustments.
> Don't go for a small coil.
> Small coils have a high resonance frequency and good sparks are difficult
> to get at these frequencies. All you get is brush like discharge and loads of
> ozone - you will have to evacuate the room very soon after.
I have noticed that ozone/NOx generation seems to be very much higher
for small high frequency systems. This may be an illusion or it may
not. I wonder if E = hv is at work in this instance?? ? Anyone
measured the amount of gases from a small and large system and
> >From other posts on this list a 4" coil sounds good although my first coil
> was 7" diameter wound on plastic gas pipe and this has worked very well
> at low power and also at higher powers. Its resonant frequency is 170KHz with
> 24" toroid and spark production is good. I was able to generate 6" sparks
> on only 1.5Kv primary voltage. I now get 45" from the same coil running at
> 11Kv and 3KVA.
> You want to aim for about 900 turns of wire on the secondary. Chose wire
> size so that the winging length does not exceed 4 times the diameter.
> Make the primary from copper pipe, refirgeration tube is good, but quite
> expensive. Coax makes a cheaper alternative remember that skin effect comes
> into play here so thin wire is no good - use the braid.
Aaarrrrgggghhhh!!! Please _do not_ use braid. You will degrade
primary Q _very_ significantly. Skin effect is exactly what makes
braid a no-no. If you don't believe me, go ahead and use it and
remember to wear heat proof gloves if you handle it after firing.