Dose the 1/4” ribbon produce more current? The ring has a starter notch so it’s 19 or later. The ring itself is set up for the wider wire, with the bosses being taller but the overall height of the ring is the same as a 3/16 mag.

Bob: I doubt it b/c according to earlier posts Ford used 1/4" from late '17 into mid '23 and 3/16 " from mid '23 to end of production in '27. I saved a Coilman post entitled "Model T Mag coils and ring 020814" which stated "Here is a chart prepared by Buzz Pound comparing all the various years magneto parts." That chart lists the info above. Best, jb

Bob, it seems to me that it would. Same lines of magnetism cutting a larger conductor should equal more current, assuming all else is equal. More current would equal higher voltage on any given load. It would also cause a larger drag on the motor.

FWIW, the field coils with the 3/16" copper replaced the 1/4" units starting in April of 1921.

Yes i say the would
FWIW
my cars have been start run just fine

Could be most car used battery for lights so didn't need the extra output for lights, Fords cost cutting saving a 1/16" of copper times 16 X number of cars.

That 1/16" is a 25% savings in mag coil copper. I respectfully submit that the reduction in copper would not significantly affect the magneto output given the limitations in coupling the magnetic field with the coils. To my knowledge Ford did not change their criteria for magneto testing when the 3/16" width was introduced. Yes narrower ribbon would restrict the theoretical maximum possible output b/c the narrower ribbon has higher resistance for the same number of turns, but I believe the magnetic excitation is no where near the theoretical limit of the coils in the mag ring. The coilman would likely know the answer, however,,,,,

This takes me back to my classes in and practice of motor and transformer design and building.

The VOLTAGE produced as a magnet passes by a coil of wire is directly related to the number of turns of wire. In other words, how many times does a line of magnetic force pass through a conductor. So, the width of the copper strips used has nothing to do with the voltage produced.

On the other hand, the AMPERAGE that a field can produce would be limited by the size of the copper strips used, as it would be limited by the gauge of wire used. Therefore, the total amperage output of a magneto is limited by the current-carrying capacity of its wires (or strips).


So, the answer to the original question would be: As long as the same number of turns of conductor is used, the width of the strips would have no effect on the voltage. At the same time, as long as the amperage output of the magneto is sufficient to power what it was designed to power, the width of the strips would have no effect.


I don't know much about the electrical needs for powering a Model T spark coil, but I have read on this Forum many times that a Coil Tester uses an ammeter to assist in properly setting the points. I get from that, that the amperage requirement of a spark coil is a known factor. And, if the magneto can produce at least that amperage over the range of speeds, then it can do its job properly.

My concern would be more concentrated on the transfer of the voltage and current from the magneto's coil, to the spark coils. There are so many possible points of resistance in that circuit, that it's hard to imagine the coils getting full voltage.

The magneto pickup collects lint. The terminal on the pickup gets oily, and/or loose. The wire is old and probably corroded, and its lugs get loose. The ignition switch is a constant source of problems. Ditto the coil box terminals and the wiring to the timer. The timer gets oily. Add up the miniscule bits of resistance from each of these and all other places, and it's a wonder the system works at all -- which suggests the magneto produces far more power than required, rendering these losses un-important.