In a message dated 98-01-03 21:59:16 EST, gprtech@frontiernet.net writes:
> 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,
Whoops! ya got me. You're right on all counts. My OF synapses misfired a
couple of times on this one. I mixed my apples and my oranges, didn't I? I
usually stew a while over my posts before I let them go out, but I sent that
one out a little too quickly.
Now that I am in contention for the "idiot of the year" award, let me make an
addition to my original post on this subject. I said to measure the voltage at
the coil with the key on to determine if you have a ballast resister or not.
Silly me, I meant to say "with the engine running." Ohms law is still in
effect - E=IR. Without I, you don't have E, and the voltage will be the same
on both sides of the resister if the points are open.
If your engine is not operable, and you have points, make sure they are
closed, and the key is on, when you make the test. If you have an electronic
ignition, the testing procedure would depend on the type of ignition you have,
and could be different than for a points type.
Also, to make sure you don't have an "artificial" ballast resister, re-measure
with the key in the start position and verify that you do have the full
battery voltage with the ballast bypassed. It is possible that you may have so
much resistance in the wires and connectors, that it looks to the coil just
like a ballast resister.
Now, I shall go join Joe curry and cower in the corner, if he is still there.
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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