Aden wrote:

Greetings Paul from Oz.

A few months ago, I was asked to build a spark generator to ionise a gas
stream.
I adapted and built up a multi-spark CDI ignition kit from a local supplier,
and it works well.
The original design was published in Silicon Chip magazine, September, 1997
(An Aust. publication)
and authored by John Clark of that magazine. It is professionally done by a
professional engineer.
It is a complete design with a number of optional triggering circuits, PCB
layouts and construction details,
and is capable of producing from 2-6 sparks per trigger up to 15000 RPM in a
4 cylinder, 4 stroke.
Waveshaping is used to reduce radio frequency noise and interference. Thus
It would be suitable for a
rotary application, particularly if multiple units are used in a redundant
configuration.

The article is about 8 pages long with photos and circuit detail, so rather
than scanning it at a decent resolution,
if you wish to email me a snail-mail address, I will gladly photocopy it and
send it to you.

The kit is available locally for $A110, and given one $Aust ~ 0.57 $US it is
a rather favourable exchange
rate (from your point of view!).

In the application I was using it for, I required a spark repetition rate of
1 KHz (free running, continuous
operation rather than triggered), and an arc length of ~ 0.5". This was
achieved with a standard automotive
ignition coil. On test, arcs of about 1" were obtained when the high tension
leads were dislodged (in air and STP).
Rather scary! Output FETs were destroyed doing this. A 1" long arc screaming
at 1 KHz generating copious
quantities of ozone is not a pleasant thing!

On test, producing an arc of  ~ 0.1" long, measured current was 6.6A at
12.5V (83W) DC input, and at about
10Hz, 1.2A (15W). I would hesitate to run the kit continuously at input
powers above 45W due to heat dissipation
limitations. Power input is roughly proportional to repetition rate between
these two data points.I have had it on test for 24 hours continuously at 45W
input without failure.

Let me know if you are interested.

Kind regards
Aden
000914
adenlindsay@australiamail.com

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org