Primary ignition voltage

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lbarron
Newbie
Posts: 1
Joined: Tue Jun 09, 2009 8:21 pm

Primary ignition voltage

Post by lbarron »

Hello, I have been thinking about the relationship betveen the primary and secondary ignition voltage patterns given by conventional spark ignition systems.
What do you think causes the primary to mirror the secondary pattern?
Is it the effect of the secondary slowing the collapse of the magnetic field, the capacitance between the 2 coils or anything else?
I have mentioned this before on the Autonerdz forum but since then i have been looking a bit more into this.
I'm not trying to answer my own questions, I just want to understand this.
Thanks for any responses.
L. Barron.

PeterF
OneWave
OneWave
Posts: 21
Joined: Thu Jun 07, 2007 10:53 am
Location: Cambridgeshire

Post by PeterF »

Hi,
The main reason the primary mirrors the secondary is that the coil is really just a step-up transformer of about 100:1 ratio. The primary voltage causes a current which is converted into magnetic flux which is then converted back into a voltage in the secondary. With a perfect transformer, no losses and no spark, the input and output voltages would be in the exact ratio of the transformer turns ratio.
PeterF.

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Autonerdz
TwoWaves
TwoWaves
Posts: 387
Joined: Wed Nov 20, 2002 4:19 pm
Location: Washington State USA

Pri and Sec

Post by Autonerdz »

Good explanation from Peter. The dynamics of coupled inductors are complex though.

Only parts of the primary mirror secondary. For example, the spark line.

Had a question about whether the primary kick is affected by secondary conditions and decided made this little silent movie. Answers the question and shows off the PicoScope really well too :shock:

http://www.autonerdz.com/flash/prisec.html

_________________
Tom Roberts
(The Picotologist)
http://www.autonerdz.com
skype: autonerdz
THE PicoScope Automotive Authority
In North America

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