General > General Technical Chat
Ignition coil question
bdunham7:
--- Quote from: floobydust on October 12, 2021, 06:13:23 pm ---I thought the vibrator still was operating when under magneto power? As long as sufficient voltage is there for it to oscillate during peaks. I'd have to hear one operating, but say 500Hz bursts at most possible 16 per crank rev?
The vibrator is part of the coil's core so always there I think, once flux builds up the contacts open. Hmm.
--- End quote ---
I don't have much experience with Model T ignition in running cars--and they are a bit unique, but magnetos that use magnets like that typically produce a pulse that reverses, but since the Model T has 8 magnets, the output looks more like a thin triangle. I have not personally connected a scope to one--if I spot a Model T I'll ask if I can throw my ScopeMeter on it! Anyway, the way I've always assumed they work is sort of like a more modern points-free solid-state small engine magneto where the magneto reversal as the center of the magnet crosses the coil is what triggers the primary opening and thus the spark. This is a bit different than the impulse-coupled magnetos that you see on aircraft and old tractors.
--- Quote from: Connecteur on October 12, 2021, 07:27:17 pm ---I haven't done the math, but I expect that a 200Hz buzzer would deliver many sparks in the part of the cycle where the ignition for that cylinder was active.
--- End quote ---
At 600RPM it will have a magneto 'frequency' of 80Hz with a peaky waveform and significant power only in the peak area. I think you're getting one spark, but I'm open to further investigation.
Connecteur:
I doubt any Model T engine ever turned at 6000 RPM,
except maybe that guy who was pulling his house,
and had just crossed the Great Divide on his way to Oregon.
bdunham7:
--- Quote from: Connecteur on October 12, 2021, 08:56:11 pm ---I doubt any Model T engine ever turned at 6000 RPM
--- End quote ---
Who is contending that they did? :-/O
amyk:
--- Quote from: floobydust on October 12, 2021, 06:04:44 pm ---I noticed somebody went full tech and made a Model T replacement Timer with microcontroller, Hall sensors, IGBT's. It looks good, would people here put one in or use the original buzz coils and timer?
--- End quote ---
:o I'd think most people who have a Model T have one because it's a simple and entirely non-electronic historical artifact, so it seems very odd to put that in it.
floobydust:
Many car show videos of the Model T's having ignition problems and dying once they get there. We have no idea of how reliable the car was in the first place. They're kinda old now. The Timer is on the lower front of the engine and no fun to access. I would rather augment vintage equipment with modern stuff if it means no more breakdowns.
The E-Timer designer is MSc EE, Mike Kossor WA2EBY so it certainly conquers the mechanical issues. Note he kept the ~500Hz buzz (multispark) to drive the coils with.
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