Quote from: multiuser on July 28, 2008, 02:55:25 PM
hi

i have replicate the curcit at the first site....

at first, without diodes ist was a "normal" spark, after, with ~10 diodes in series was nothing... no spark...
but after trying x times, there was a SUPER BOOOOOM... 20 times a very very strong an very loud spark...

but now... it is death again?! why?

why doesn't it function once and then again?
and anyway, which has it with the diodes in series up itself, since it is actually a short-circuit?

http://de.youtube.com/watch?v=5hQx68BiNc4
http://de.youtube.com/watch?v=YOTUniF7K54

Which circuit did you replicate as I saw a capcitor bank in you video and two ignition coils?

Quote from: multiuser on July 28, 2008, 02:55:25 PM
hi

i have replicate the curcit at the first site....

at first, without diodes ist was a "normal" spark, after, with ~10 diodes in series was nothing... no spark...
but after trying x times, there was a SUPER BOOOOOM... 20 times a very very strong an very loud spark...

but now... it is death again?! why?

why doesn't it function once and then again?
and anyway, which has it with the diodes in series up itself, since it is actually a short-circuit?

http://de.youtube.com/watch?v=5hQx68BiNc4
http://de.youtube.com/watch?v=YOTUniF7K54

Holly smokes multiuser, are you charging that cap bank to 300 volts? how many uf do you have there?

Luc

Quote from: Ursine on July 28, 2008, 09:14:04 PM
Hi All,

I've stumbled upon this thread last week and can't stop thinking about it. I'm set to get the parts for the circuit but have a few questions:

1. I'll be getting a new inverter (solid state) and I understand these are not as tolerant of circuit spikes. What measures can take to protect it. Is that what the light bulbs are for?
2. How fast does it take to charge the cap. Once I understand what's happening, I'll try it in my grass trimmer engine. I'm thinking of bypassing the magneto and pulsing the circuit from a cam on the output shaft. The speed will be limited by how fast the cap can charge.

Thanks,

Dave

Hi Dave, welcome aboard.  I would suggest to not use the inverter to start. Many have fried them during testing. Just do as I did in my updated video: http://www.youtube.com/watch?v=FxnRQ7fkWtE  and plug in the full wave bridge rectifier in the wall to start your testing. Once everything is working well if you want to test with the inverter then use a 60 watt light bulb in series on one side of the inverter to protect it from overload.

Luc

@Gazza
I'm a little confused by your circuit. 
You have a microwave transformer between the timing circuit and the ignition coil.
A microwave transformer steps up the voltage about 18x while stepping down the amperage,
which means you are putting over 200 volts into the 12 volt side of the ignition coil.
You need a high current low voltage for the coil for it to work right.
200 volts will be stepped up so high that the HV output will short across the windings inside the coil.
12v to 12,000v  means 200V are stepped up to 200,000V.


You left out one key part in Dave's circuit, he has a diode connected across the LV input of the coil.
This diode removes the back emf spike caused by the coil.
That is probably what is blowing your resistors.
Check it out:
http://jnaudin.free.fr/wfc/D14.pdf
You see the 1N4007 just above the MOSFET  across the input of the coil? 

Hope this helps.

@gotoluc, adamhy

yes, i have about 300 to 330 volts and 2 ignition coils in parallel.
the capcitor bank is about 2980 ?F. 8 capcitors (450V) parallel, because i have no other...