>From: kristian@cs.uchicago.edu
>Subject: Ballast resistors and coils
The wire in question is indeed an inline chunk of restistor wire feeding
the primary side of the coil. It's only failure mode is to burn completely
through, hence no power.
>Does anyone know the principle behind
>using a "wire" as a resistor, rather than a separate resistor?
>>I'll take a stab at this, altho' in no way do I profess to
be electronically inclined.
I think the reason behind having the wire instead of a
simple resistor is that the ballast resistor wire
begins to heat up immediately after the key is switched
on (and thus start-up), causing the resistance across
the wire to increase and thus reducing the voltage to the coil when
the car is in run mode. Compared to start mode when the
ballast would be cooler, thus less resistance, thus
more voltage to the coil, thus hotter spark for
start-up. That's probably why the ballast is insulated in
ceramic (low heat coefficient), as opposed to just
electrically insulating it, which would be much
cheaper.
Time to introduce myself to you and the list. My name is Randy Wilson,
and I broadcast these messages out to the real world from a small apartment
in Norfolk, Va. It appears that I'm backwards from most of the folks here.
Computing for me is purely a hobby. I make my living fixing British and
Italian cars.
>>Lucky you. You have my hobby as your job, and my job
as your hobby. Some guys get all the luck ....
Welcome aboard !
dstone@sc9.intel.com
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