electrical terms - motors versus car ignition systems
electrical terms - motors versus car ignition systems
(OP)
On a hot rod engine bulletin board there is a discussion about CDI ignitions reflecting a bunch of Joules back to the battery instead of making spark.
http://speedtalk.com/forum/posting.php?mode=reply&...
Terms like reactance and real and imaginary power when describing steady state conditions in motors etc are just buzz words to me.
Do they need to be considered for ignition spark evaluation too/
thanks
Dan T





RE: electrical terms - motors versus car ignition systems
Hmmm...
RE: electrical terms - motors versus car ignition systems
The DC side of the CDI (the battery) should be feeding the DC-DC converter within the CDI circuit.
There's not really any mechanism for "joules" to be routed back to the battery.
The secondary circuit path at the point of ignition spark should have nothing to do with the battery as such.
By the way, the link you've provided requires Login.
RE: electrical terms - motors versus car ignition systems
http://speedtalk.com/forum/viewtopic.php?f=1&t...
Still, I imagine this is based on a basic misunderstanding of what the OP in that other forum was looking at.
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RE: electrical terms - motors versus car ignition systems
Dan - Owner
http://www.Hi-TecDesigns.com
RE: electrical terms - motors versus car ignition systems
The advantage that I see, for inductors, is that it has a much higher compliance than a capacitor, i.e., if the resistance of the load increases, the capacitor will drop in output current, while the inductor will continue to try and dump its current. That's just seems to be an extra degree of freedom that the capacitive circuit doesn't have.
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RE: electrical terms - motors versus car ignition systems
RE: electrical terms - motors versus car ignition systems
RE: electrical terms - motors versus car ignition systems
Generally speaking, A CD ignition has a capacitor that is charged and then switched onto the primary coil leads. The charging circuit feeding the capacitor also typically has a transformer with a switching circuit on it's primary side between the battery positive lead and this capacitor. The circuit path when the capacitor is switched across to the coil leads doesn't include the battery so it'd be impossible for energy to be "sent back" to the battery.
The opposite polarity voltage he's seeing on the primary side of the coil after the spark event is likely a snubber circuit that is discharging the remaining magnetic field in the coil so it's ready for the next spark.
RE: electrical terms - motors versus car ignition systems
Dan - Owner
http://www.Hi-TecDesigns.com