Electrical igniter for gas engines A keystone to understanding by Magluvin

[delboy]

Hey Delboy

Lets say the primary is a few turns, If we discharge 100v into it, what amount of turns are we looking for on the sec. ? And should it be of the traditional Tesla coil look and type, or are we looking at a Kapanadze style?  Spacing between windings?
Bifilar?  Is there any need for bifi here?  =]

Mags

It should be traditional Tesla spiral pancake coil, but as big as posible, find the place in your room NO BIFILIAR ANYWHERE!
One more requirement is that secondary should be wounded from center to outer diameter in clockwise orientation!
Spacing between windings not needed if isolation is good, but always put some for example only 1-2 mm between secondary windings. But if you ask for spacing between primary and secondary than put minimal spacing same as secondary (1-2 mm) because few turns of primary need good connection with few secondary turns. In global you get loose connection (secondary always have at least 50 times more turns) that is required for free oscilation.
Originaly for secondary you should have 1/4 wave length for used frequency, wounded in spiral form to get some inductivity (of course it should be large because of needed high Q) and small resistance (thicker wire for example AWG18) And that is big problem, because if you use 50kHz you will have to wound one mile of wire , and of course nobody stops you to try with smaller one.

[Magluvin]

Hey Delboy

So the sec. oscillates on its own?  No cap?    Also, the primary should be at the perimeter of the sec.?

Hmm  1 mile of 18awg,  thats a big roll. =]

Thanks Delboy

Have you heard of the TRISIL devices that I am playing with?  Just wanted to know what you think.  ;]

Mags

[delboy]

Hey Delboy
So the sec. oscillates on its own?  No cap?    Also, the primary should be at the perimeter of the sec.?
Hmm  1 mile of 18awg,  thats a big roll. =]
Thanks Delboy
Have you heard of the TRISIL devices that I am playing with?  Just wanted to know what you think.  ;]
Mags

Secondary should have cap because of resonance and it should be for example simple metal ball , enough big for required capacity depending how big is resonant frequency and how big power you want to have oscillating. Yes primary should be on outside and secondary inside.
What kind of TRISIL devices, give me link.

For shorter secondary you must use higher frequency, for example Tesla used 250kHz in patent 645576 so that value gave him only 300m required for 1/4 wave length, and he used 50 turns in secondary that was 2,44 meters in diameter. Higher the frequency bigger the losses on ground level. Tesla used higher frequency for demonstrating transfer of energy in higher elevation (>10km) through Air while he somewhere else recommended range (30-50)kHz for transfer of energy through Earth

[forest]

delboy

can you help me (I thin other could be interested too). ?
in case of using this scheme we should be able to use existing flyback coils or car coils for lower frequencies.However there is one big problem - how to measure secondary wire length of such nice coil  without destroying coil ?
If we could use a generator and a scope to measure exact length of secondary (and primary) of such coil we would easily adapt circuit frequency to 1/4 wavelength
Everything else is measurable using proper multi-meters or equations.

[delboy]

delboy
can you help me (I thin other could be interested too). ?
in case of using this scheme we should be able to use existing flyback coils or car coils for lower frequencies.However there is one big problem - how to measure secondary wire length of such nice coil  without destroying coil ?

If you know exact dimensions of coil, and number of turns, than you can calculate approx length of wire used by formula L=N*D*pi   if only one layer used, and if multilayer than D should be D=(D1+D2)/2
D1 - outer diameter
D2 - inner diameter of coil
Other problem is that car coil is not optimised as Tesla suggested 
-Both,primary and secondary have high active resistance because thin wire used,
-there is ferite core used, and you are limited with high frequency
-small dimensions give small energy accumulated because this is designed only to fire the sparks
-design is cilindrical coil of several thousand of turns (not spiral form which is minimizing capacity of coil) giving high capacity to coil that will eat up all energy and nothing left to oscilate when potential reach high level
- etc. ....