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June 29, 2004
One additional thing to pour into the stew, most cars have an accessory
position on the key. That is to keep current from flowing through the coil
for a long time un interrupted by the points. As some one pointed out. If
you are getting 12 vdc to the coil and it is interrupted by the points
running at, say, 3,000 rpm, the measured voltage will be less than 12 vdc
and the length of time the coil is generating heat is less than 100% of the
time. (A smart person could figure out what percentage with rpm, dwell
etc.) (the actual voltage will still be 12 vdc but a normal meter will only
read the average because it is less than 100% of the time. In the case of
turning on the key and if the points happen to be closed at the time, the
coil will pull full current with no interrupted cool down cycles and would
most likely get too hot as well as the points could weld together or be
warped or damaged by the prolonged heat. Thus the accessory position for
listening to the radio when not driving etc. Of course, obviously, this is
true for a normal old fashioned points/coil system. I don=92t pretend to kn
ow
much about Capacitive/Discharge systems and other more exotic systems.
Bob
"Robert D. Gardner" < rdgard@... > 32818
Posted on June 29, 2004 04:55 PM
Posted to category(s) Cooling System | Ignition System | Suspension & Steering
