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need High voltage ignition for hybrid, modified stun guns?

Posted: Tue Jan 10, 2012 12:08 pm
by BigBang J
Hello I am still working on my hybrid, and I am looking for a small battery powered ignition system. My hybrid will be hand held and is pretty small, so I need the ignition device to be small as well. Stun gun internals would work great, but I have tried stun guns in the past and I had a hard time with insulating the wires and terminals. Anybody know how to modify them to produce a lower voltage? I am thinking in the range of 15- 20kv. I will be running 15-16x and my spark gap is about 1/16".

Thanks guys!

Posted: Tue Jan 10, 2012 12:28 pm
by jackssmirkingrevenge

Posted: Tue Jan 10, 2012 12:48 pm
by Technician1002
Voltage is fixed by the breakdown voltage of the air in the gap. A shorter gap has a lower breakdown voltage. A higher pressure has a higher breakdown voltage. Once an arc is established, the voltage is reduced and is based on ohm's law. The higher current, the lower the resistance in air so a high current arc can be very low voltage. The arc on an arc welder is often in the 20-80 volt range.

The high current of the spud gun makes an excellent hybrid ignition source. Use high voltage ignition wire with a solid conductor instead of fiber high resistance radio suppression wire. Another place you may be able to obtain high voltage wire with a solid conductor is a good sign shop that does neon signs. The high voltage wire taken from a flyback transformer also works.

Your main issue will be insulating the connections so you don't get zapped. From a good electronics shop (not radio shack) pick up some high voltage potting compound or high voltage RTV. Use the stuff designed to stop corona discharge from high voltage connections.

Posted: Tue Jan 10, 2012 7:56 pm
by POLAND_SPUD
you can use an ignitor module for propane ovens
[youtube][/youtube]

got mine for like 8$ or so

Posted: Tue Jan 10, 2012 7:57 pm
by jimmy101
Technician1002 wrote:Voltage is fixed by the breakdown voltage of the air in the gap. A shorter gap has a lower breakdown voltage. A higher pressure has a higher breakdown voltage.
And, the breakdown voltage is also a function of the sharpness of the electrodes. Blunt electrodes in air at 1 ATM breakdown at about 3KV/mm, sharp points (like needles) will break down at about 1KV/mm. So, using sharp electrodes will reduce the breakdown voltage of the gap and reduce the insulation requirements for the wiring.

Posted: Tue Jan 10, 2012 9:12 pm
by Zeus

Posted: Tue Jan 10, 2012 9:31 pm
by BigBang J
O.K. thanks for all your inputs, I planned on using wire from a flyback transformer which is rated for 25 or 30kv. Actually I think my spark gap is smaller than 1/16" but I know it's not larger, I can't measure it since it is currently installed in my chamber.

Hey Poland, what voltage input do those propane oven ignitors run off of? and do you know how many volts out? Where did you get yours?

Technician1002:
I understand all you said except for, "The high current of the spud gun makes an excellent hybrid ignition source" please clarify.

Posted: Tue Jan 10, 2012 10:00 pm
by BigBang J
Hey awesome link zeus,. I think I will give that a try. Very compact and seems like it will be powerful enough. Now I just need to get my hands on a camera.