Re: Safety Gap

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Safety Gap
From: Tesla List <tesla-at-stic-dot-net>
Date: Mon, 17 Nov 1997 01:02:02 -0600
Approved: tesla-at-stic-dot-net

From: 	Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
Reply To: 	bert.hickman-at-aquila-dot-com
Sent: 	Sunday, November 16, 1997 10:48 AM
To: 	Tesla List
Subject: 	Re: Safety Gap

Tesla List wrote:
> 
> From:   Vivian[SMTP:V.C.Watts-at-btinternet-dot-com]
> Reply To:       Vivian
> Sent:   Saturday, November 15, 1997 4:14 PM
> To:     Tesla List
> Subject:        Safety Gap
> 
> Snip
> >The safety gap for your neon's should actually consist of two smaller
> >gaps - each going to a center RF ground, which is also tied to the case
> >of the transformer(s).
> >
> >Safe coilin' to you!
> >
> >-- Bert --
> >
> 
> Thanks Bert for inf..  From what I can make from your ASCII diagram
> it looks as if you have the centre tap of the neon secondary grounded
> or is this just the neon case?  My transformer has a secondary centre
> tap and associated earth lug (mains earth)  which I have deliberately
> removed.
> 

Normally, this would just be the neon case (which is also the center-tap
for the secondary on most trannies). The objective of the center
electrode is to provide a safe path to ground if you sustain a secondary
strike to the primary circuit. The core would normally also be tied to
this point just to make sure that, if the transformer instead flashed
over from the secondary to the core, the core doesn't rise to a
potential where it woul;d then arc over to the primary, sending high
voltage back through your power mains. :^(

> Yes I have matched the capacitor to the neon for Max power transfer.
> I was also wondering that if I only run the coil for a minute or so
> at time if I could use a larger capacitor.   The neon is a 10,000Kv 50ma.
> This give a source impedance of 200000 Ohms and at 50Hz a
> capacitor of 15nF.  But the transformers DC resistance if only 5.6K.
> The inductance is greater than 20H (off the scale on meter).
> 
> I could try and see what the regulation is by running it with a lower
> input voltage and loading the output.  Is this at all feasible or
> am I trying my luck and should be thankful it works well now?
> 
> Thanks again for help
> Viv Watts UK.

Just try adding a bit more capacitance and retuning the system!
Identically made transformers actually have a range of current-delivery
capability. As long as your transformer can provide sufficient charging
current to your tank cap to permit repeatable gap refiring, you should
be OK. Eventually you'll reach a point where coil output declines as the
tank cap voltage starts sagging due to insufficient recharge current.
BTW, for your trannie, the "apparent" inductance of the secondary in
operation is over 500 Henries...(!)

Safe coilin' to you!

-- Bert --