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Discussion Starter #1
I understand the theory.
A normal inductive field is developed.
The Collapsing of the field is caused by (whatever) holds the field from collapsing, suddenly shorting the field to ground.

Points used to do that.

There must be some component parts inside that Magnetron Coil.
Does any body have a Schematic?
Anybody know what's in there? Must be at least on Cap. and maybe a Transistor circuit wired as a switch.

I have a broken (Shorted) Magnetron I'm going to look at. I was hoping for some hints. (PS: the replacement for a 16 Hp B&S L-head twin is $49 here)
 

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Discussion Starter #2 (Edited)
Here's what the Kart guys say about the Magnatron.
magnatron darlington.gif

it works better than the old points ever did. Here's how: The magnetron coil actually contains 3 separate coils of windings. In addition to the primary and secondary windings, there is a 3rd winding, called the "trigger" coil." When the leading edge of the magnets in the flywheel approach the coil, the magnetic field surrounding those magnets generates a small voltage (about 1 volt) that powers a solid-state switching device called a Darlington Transistor, turning the transistor "on." That "on" mode completes the circuit on the primary winding and a current of about 3 amps flows to ground on the crankcase (Figure 2). As the flywheel continues to rotate that current builds the... <http://www.foxvalleykart.com/timing2.html>
But suffice to say, when the revers coil is energized it turns on the Darlington pair which short the Primary windings to ground. Just like the points did.

That Darlington pair is probably a black dot about the size of a match head in the Potting of that Magnatron.:trink40:
 
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