Homemade miniature spark igniter; improved version

[Jan Ridders]

Hi all interested,
Some few years ago I made a simple and cheap spark igniter for small IC model engines using the electronic circuit out of a cheap ("Blokker") kitchen gas lighter. I now made a new version of it eliminating a thyristor that appeared to be somewhat vulnerable in certain circumstances. This version is much more robust and quite reliable and even easier to make.
See the instruction video:
[ame="https://www.youtube.com/watch?v=09R6teBOlco&list=UUOWqwLEIfORZB09qQirdkag"]https://www.youtube.com/watch?v=09R6teBOlco&list=UUOWqwLEIfORZB09qQirdkag[/ame]
and the concerning page (bottom part) on my web site for further details and some suppliers for this kind of gas lighters:
http://ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_crcuit_frameset.htm

Friendly greetings from Holland,
Jan Ridders

 

[cfellows]

Thanks for posting this, Jan. You've made a great many contributions to the model engine building community and your efforts and generosity are much appreciated.

I need to try and find one of these igniters here in the U.S.

Chuck

 

[BaronJ]

Hi Jan,

Nice find and conversion. Simple and effective. This circuit could just as easily be used with conventional points or if you wanted to stay with a reed switch a higher voltage rated thyristor. I note that the original is only rated at 100 volts. They are available in that size to about 400 volts. Though the current flow could be too much as well.

Or (note I haven't tried this) a magnet and a coil in a similar fashion to a magneto. In which case you could do away with the battery.

PS. Nice video.

 

[creast]

I originally tried the Blokker circuit and can confirm problems with thyristors blowing with regularity even though they are rated 600v. I was trying to trigger via a hall effect but could not find a device that would work as low as 1.5V that the Blokker works on. You can't up the voltage as the HT just flies sky high. In the end I abandoned this route and it has been a tortuous path to get what I wanted. I have copied the Blokker HT coil and now wind my own as the Chinese parts don't like being re-soldered much as the plastic melts.
I am sure this new circuit will be far more reliable and if I ever decide to use a microswitch to trigger then I will definitely return to this circuit.
Great work Jan.. you always impress and are kind to share your plans with the community.

 

[BaronJ]

I originally tried the Blokker circuit and can confirm problems with thyristors blowing with regularity even though they are rated 600v. I was trying to trigger via a hall effect but could not find a device that would work as low as 1.5V that the Blokker works on. You can't up the voltage as the HT just flies sky high. In the end I abandoned this route and it has been a tortuous path to get what I wanted. I have copied the Blokker HT coil and now wind my own as the Chinese parts don't like being re-soldered much as the plastic melts.
I am sure this new circuit will be far more reliable and if I ever decide to use a microswitch to trigger then I will definitely return to this circuit.
Great work Jan.. you always impress and are kind to share your plans with the community.

Hi Guys, Creast,
The output voltage is limited by the size of the spark gap ! If you are trying to run this circuit without any kind of load you will get voltage breakdowns all over the place. As far as upping the voltage is concerned it will work quite happily at six volts bearing in mind the previous comment. In air the breakdown voltage is about 1000v per mm and the output terminals are only about 12 mm apart, so good insulation and a long creep path are needed if you do this.

The thyristor problem is that there is no snubber to control the rate of voltage rise across it. I thought that the original Blokker only had a 100 volt device. One with a 600 volt rating should, with a snubber laugh at this duty.

 

[BaronJ]

I originally tried the Blokker circuit and can confirm problems with thyristors blowing with regularity even though they are rated 600v. I was trying to trigger via a hall effect but could not find a device that would work as low as 1.5V that the Blokker works on. You can't up the voltage as the HT just flies sky high. In the end I abandoned this route and it has been a tortuous path to get what I wanted. I have copied the Blokker HT coil and now wind my own as the Chinese parts don't like being re-soldered much as the plastic melts.
I am sure this new circuit will be far more reliable and if I ever decide to use a microswitch to trigger then I will definitely return to this circuit.
Great work Jan.. you always impress and are kind to share your plans with the community.

Hi Guys, Creast,
The output voltage is limited by the size of the spark gap ! If you are trying to run this circuit without any kind of load you will get voltage breakdowns all over the place. As far as upping the voltage is concerned it will work quite happily at six volts bearing in mind the previous comment. In air the breakdown voltage is about 1000v per mm and the output terminals are only about 12 mm apart, so good insulation and a long creep path are needed if you do this.

The thyristor problem is that there is no snubber to control the rate of voltage rise across it. I thought that the original Blokker only had a 100 volt device. One with a 600 volt rating should, with a snubber laugh at this duty.

 

[creast]

Hi Baron J,
Sorry, iwas wrong , the MCR 100-6 is in actual fact a 400v rating but they do a 100-8 which is 600v. Either way, as you say, the 400v units do tend to cop out when used as an ignition circuit. As a kitchen gas igniter it never gets high enough due to the diode trigger at 100v ish.
Have you actually run this at 6 volts in ignition mode or just as free oscillating sparker?
In ignition mode the capacitor is charged to around 200v with 1.5v input so at 6v you will be getting far too high a voltage to dump in the HT coil primary.

 

[BaronJ]

Hi Creast,

There is no problem running at a higher voltage as long as you are aware of the consequences of doing so. Yes the output voltage will increase too much if you let it. This is one of the reasons for the loading resistor, it stops the voltage from getting too high. Also the diode will break down and avalanche at some voltage above its reverse rating, limiting the output voltage. Whilst the transformer will multiply the voltage fed into it, its the amount of current that you put in that gets transformed as well, giving a hotter spark.

HTH.

 

[gus]

Hi HMEM Gurus,,
Am putting this good idea into reply HMEM folder just in case I could locate USA/EU stove lighter. May hijack my darling boss's .
Now in South Thailand with some fishy folks.

 

[BaronJ]

Hi Gus,

Not spoken to you for a little while.
Its quite easy to build an ignition system using some salvaged bits. Most scrapped or non working LCD displays will yield a couple of high voltage transformers that can be pressed into service, though will require a higher drive voltage than 1.5. But the gas igniter's are a very convenient starting point.

Did you get your RT finished ???

 

[Looper7]

BaronJ and Creast thanks for the dialogue the lights are starting to come on upstairs for me.

Jan your webpage truly is inspiring thank you


Jeff

 

[gus]

Hi Gus,

Not spoken to you for a little while.
Its quite easy to build an ignition system using some salvaged bits. Most scrapped or non working LCD displays will yield a couple of high voltage transformers that can be pressed into service, though will require a higher drive voltage than 1.5. But the gas igniter's are a very convenient starting point.

Did you get your RT finished ???

Will use RT for circular(semi/quarter) profiling. 71 t wormgear no good for dividing.. Bought 60t worm gear to divide. I have extra set of material to make a backup RT. Looks like I am practicing on making better/best RTs.;D

Now in South Thailand with friends enjoying the local food.

 

[BaronJ]

Hi Gus,

Sorry the gear didn't quite work out as it should have.

I wonder if you saw this thread ?
http://www.woodworkforums.com/showthread.php?t=183460

Thailand !!! BIL lives there somewhere around Bangkok. We keep suggesting that we would like to visit, but he won't tell us exactly where he now lives. :wall:

Anyway I hope the fishing is good.