Re: Triggered gap and safety gaps

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

Original poster: "Shaun Epp by way of Terry Fritz <twftesla-at-qwest-dot-net>" <scepp-at-mts-dot-net>

Hello Group,

Although I'm not currently building a triggered spark gap, but I have some
info that may help, and I find this interesting too.

First off, there are high energy ignition coils available for a high price
that will give a higher current and voltage pulse.  I have experimented with
both an a useful cct call the "Lightning Lamp".  I used as Accel Super Coil
to power it and it rocked man!!.  With a regular surplus coil, i could get
~2 inch sparks in air and it really bite if it gets ya  =8-O . With the
super coil, I was pulling 4 inch sparks that were much thicker and by
changing the series capacitor for 2uF to 4uF I had it acring internally
after I tried to prevent it from flashing over its voltage darn,,   oops !.
It's an article was from popular Electronics magazine from approx 10 years
ago, The project uses a Triac & Diac combination called a Quadrac and is
basically a light dimmer cct, without adjustment, but this could be added.
Note, the capacitors, 2uf -at- 400 Vdc  are small metalized polyester or
polycarbonate,  about the same as your thumb nail...... much cheaper that a
motor start cap.

  Another thing I discover is that the ignition wire used mostly today is
highly resistive to reduce interference with electronics and the radio.  So
if its not shiny silver wire, and black cabon looking, don't use it.  The
resistance is 10Kohms /foot or more.


triac         2uF
              ----------[
3amp]-------------o--------------|<|---------|[--------o
                                                           |
|>| \                        |
                                                          == 0.2uF
\                       |
            120 volts                                |------------|<|----- |
| ignition coil
           ac filtering                            _|_               |>|
diac                       |      8-------HV
                                                         |  |
|      8
                                                         |  | 400 Kohm
pri  8 | | 8
                                                         |_| resistor
8 | | 8
                 common                            |
|      |
            --------------------------------o-------------------------------
------o---o---------



another item I've read about is triggers.  I've seen diodes in series with
pulse transformers to allow posistive going pulses only and protection, they
from these diodes, small capacitors from there to the common return.  The
trigger electrode is inline with one of the spark gap electrodes, not part
of it.  This arrangment was used in a high energy  pulse supply.
Question:  Could it also be used for tesla Coils???

Any comments I look forward too?
Shaun

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, August 02, 2001 12:33 AM
Subject: Re: Triggered gap and safety gaps


> Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<bert.hickman-at-aquila-dot-net>
>
> Marc,
>
> There was probably enough parasitic capacitance to provide a low current
> "displacement current" spark, but it might not have enough energy to
> consistently trigger the gap. A nice, hot, high current trigger pulse is
> what you want to consistently trigger the gap...
>
> -- Bert --
> --
> Bert Hickman
> Stoneridge Engineering
> Email:    bert.hickman-at-aquila-dot-net
> Web Site: http://www.teslamania-dot-com
>
> Tesla list wrote:
> >
> > Original poster: "Metlicka Marc by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
> >
> > bert,
> > in my early "RAW" circuit, i didn't provide this return path. i grounded
> > the case of the nst, the dimmer case and the nst filter circuit ground
> > term., could this have been why the safety gap would fire every once in
> > a while? i wondered were the trigger energy was going, i thought maybe
> > it was following the main tank energy around the primary?
> > i am setting up to try terry's setup now.
> > marc m.