Does someone know what I have here?

[gidge348]

Hello I have been a viewer of this website for quite some time but have not really put anything up as I feel a bit intimidated by all these very bright people that comment on this site.

Well here goes, I have RR Nimbus that I am modifying the gearbox on to go in salt lake racer here in Australia.

Been going through my boxes of eBay purchases and turned up this that I bought some time ago, an opposite polarity ignition unit for use with a “coil”. Thought it may be a good spare if I need one for the Nimbus.

When plugged in it buzzes like a normal igniter box, but no spark tried connecting to an automotive type coil... nothing.

Is there some other type of aviation/turbine coil?

Is this RS?

Have I hooked it up wrong?

Is this not an igniter box?

Any information gladly received.

Thanks again
Ian..

[turbochris]

I think I know, stick your fingers in those ceramic holes and try it again,

[cursorkeys]

Heh, and see if your eyes light up?

The only usage of 'vibrator' I've seen is in American electronics and it just means a self-oscillating coil to give a square wave output for something. So, it sounds like it's an ignition exciter box that drives an external HT coil.

I'd have done exactly what you did and put a car ignition coil on the output and expect some HT.

Can you put a scope on the ouput and see what's coming out of it?


Edit: Those HT style output posts do seem suspicious. Some gas lasers have a 2 part ignition system with a DC HT output and a 'tesla' transformer with a cap and a spark gap to provide a high-current pulse to get the thing ionised. So the box could be HT but low current and expecting the previously mentioned components to complete the system.

I guess that isn't the most likely setup but if you connect a scope I'd use a HT probe until your sure it's LT DC coming out of that thing.

[gidge348]

He he he..... Chris, I actually thought of sticking my tongue in there but I have not got much hair left at the best of times and few thousand volts would not improve that.

Thanks Cursor Keys, after your post I decided to do a little surgery and have a look inside at first I was a bit excited, looks like a couple of capacitors hooked up to the output terminals and some other assorted bits.

Then looked at the leads going to the output connectors and they looked a bit puny to run an igniter plug.

I thought about your comment on the usage of the word “vibrator” and pulled out one of the “capacitors” (actually vibrator unit) the numbers on the side lead me to site that identified it as a “shower of sparks” unit for starting a magneto ignition piston air craft.

When the engine is at slow cranking speed the magnetos will only produce a very weak spark, the “shower of sparks” will produce many more sparks so the chances for the fuel to ignite are greater.

Not sure if I can adapt if to turbine igniter but found a few wiring diagrams so may have a play in the future.
Thanks again for your help.

Ian...

[gidge348]

Ok, had a play and got some sense out of the top output, seems to buzz a 115hz spark up to about 12mm and breaks down at about 18mm. Have not tried it to start an engine, does anyone have a comment as to if it will work or not.

Regards

Ian...

[racket]

Hi Ian

My Treager text shows "Opposite Polarity Ignition Systems" were an early form of gas turbine ignition systems ( GE J47 engines) , the twin outlets from the "vibrator unit" each fed twin ignition coils ( 4 total) sending sparks to 4 "electrodes" , with a pair of electrodes.... "each electrode alternately become highly positively and negatively charged , thus causing a very high potential difference to exist across the electrodes "

Hope this helps

Cheers
John

[gidge348]

Jul 29, 2013 4:32:19 GMT -5 racket said:

Hi Ian

My Treager text shows "Opposite Polarity Ignition Systems" were an early form of gas turbine ignition systems ( GE J47 engines) , the twin outlets from the "vibrator unit" each fed twin ignition coils ( 4 total) sending sparks to 4 "electrodes" , with a pair of electrodes.... "each electrode alternately become highly positively and negatively charged , thus causing a very high potential difference to exist across the electrodes "

Hope this helps

Cheers
John

Thanks John,

That makes sense as I was only able to get a reaction using the top outlet, that on its own seems to give a pretty decent spark. I think I will have to do a little bit more head scratching as to how to wire it up. If I can get it to work using both outputs I think I would just about be able to use it as an arc welder...

[racket]

Hi Ian
This diagram might help

[racket]

Bugger didn't go , will try again