Re: Explain how Ignition Coil works?
A magneto consists of five parts:
An armature. In the above magneto, the armature is shaped like a capital "U". The two ends of the U point toward the flywheel.
A primary coil of perhaps 200 turns of thick wire wrapped around one leg of the U
A secondary coil of perhaps 20,000 turns of very thin wire wrapped around the primary coil
A simple electronic control unit that commonly goes by the name "electronic ignition" (or a set of breaker points and a capacitor)
A pair of strong permanent magnets embedded in the engine's flywheel.
When the magnets fly past the U-shaped armature, they induce a magnetic field in the armature. This field induces some small amount of current in the primary and secondary coil. What we need, however, is extremely high voltage. Therefore, as the magnetic field in the armature reaches its maximum, a switch in the electronic control unit opens. This switch breaks the flow of current through the primary coil and causes a voltage spike (of perhaps 200 volts). The secondary coil, having 100 times more turns than the primary coil, amplifies this voltage to approximately 20,000 volts, and this voltage feeds to the spark plug.