Homemade CDI

Jun 03, 2006 34 Replies

To keep running.

The OP sayed 30000 RPM. 2 or 4 stroke?

Nick

Not only to keep running, but also to get more power and rotations. At start we set the cdi on 5° BTDC to start the engine easy. If the engine runs, the egnition will go to (depent on engine) ~35° BTDC (normal ignitionpoint) From ~8000 till xxxx rpm we lett the ignition go to =>40° BTDC to get more rpm. Belowe the 8000 rpm you can set the egnition to get more power.

On 2 stroke (like Zenoah PUM260) it will over 30.000 rpm. Overhere you can see wat kind of spark we create

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I'm surprised he didn't correct Wayne about CDI...:-)

Tom

Do tell, What did I get wrong?

>

Very true, but at 6V not 600V and only at DC and small currents. That 1F cap you linked to is only a 159uF cap at the 1kHz they measure the ESR at. It's also very telling that they don't mention the current or dissipation it can cope with, on the face of it you could apply a 2.5V RMS square wave to it at

1kHz without exceeding the data sheet ratings, but the 6.25W it would dissipate would surely destroy it.

On the other hand that cap I mentioned can have 415V 50Hz applied to it continually for it's life time.

Apologies if my maths is a bit out as I've had a very long day at the machinery auction in York.

Greg

Correcting a ludicrously inaccurate statement that has been repeated as if it's fact is not being a pedant, though it may be annoying to a person who makes such statements 8-)

Greg

Duh?? Or did you want me to say "capacitive" If it means something else then it's news to me! Tell me what you think it means?

I think he's being pedantic 8-)

Greg

Dwayne, I can see this becoming pointless..

Get to the point then FFS. Oh well back to work! >

--Aha! Thanks; makes sense now. I was under the mistaken impression that the cap would limit speed to a couple of hundred rpm but it seems the thing charges up a *lot* faster! :-) Guess I gotta build me one now, heh.

Maybe Tom will help you! He seem to be more enlightened than the rest of us, but seems to want to keep it close to his chest ;-)

Wayne...

Maybe this can help

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