In order to generate the same spark energy (watts) the 12 volt coil would
draw only half the current of a 6V coil. Amps times volts equal watts.
Moreover, since you're still applying 12 volts to the coil and ballast in
series, half of the power (watts) is wasted in the ballast. This really a
simplistic view, since the ballast is designed to limit the peak current,
and not actually split the voltage, but the current draw fro the same energy
would be more for the ballasted coil.
George Richardson
'57 TR3, TS15559L
(getting ready to paint - and now on the web!)
http://www.merlingroupinc.com/tr3.htm
-----Original Message-----
From: DANMAS <DANMAS@aol.com>
To: cb1500@erols.com <cb1500@erols.com>
Cc: triumphs@autox.team.net <triumphs@autox.team.net>
Date: Saturday, January 03, 1998 7:51 PM
Subject: Re: Spitfire coils - superfluous information
>In a message dated 97-12-31 17:20:06 EST, cb1500@erols.com writes:
>
>> What you say about internal "resistance" vs. external "resistor" makes
>> sense. My next question: Even though they operate differently, are both
>> systems meant to keep the coil from overheating when the engine is not
>> running, and with the ignition switch in the "ON" position?
>
>Charlie,
>
>I would not think so. Under running conditions, the ballasted coil would
pull
>roughly the same current as a non-ballasted coil, in order to provide the
same
>spark energy. It would be approximately the same as if you left the key on
in
>an older 6 volt automobile. Of course, there are so many variables
involved,
>it would be difficult to give an absolute answer.
>
>Dan Masters,
>Alcoa, TN
>
>'71 TR6---------3000mile/year driver, fully restored
>'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion -
see:
> http://www.sky.net/~boballen/mg/Masters/
>'74 MGBGT---3000mile/year driver, original condition
>'68 MGBGT---organ donor for the '74
>
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