COVER-CASE 3T8875 - Caterpillar

Magneto
Illustration 1 g00743710
Magneto
(1) Alternator
(2) Stator The main components of the magneto are alternator (1) and stator (2). The alternator generates electricity. The stator distributes the electricity. There are no brushes or distributor contacts.
Illustration 2 g00579848
Cross section of the magneto
(3) Rotor
(4) Vent
(5) Speed reduction gears
(6) Pickup coil
(7) Drive tang
(8) Storage capacitor
(9) Rotating timer
(10) Silicon controlled rectifier (SCR)
(11) Output connector The magneto's drive tang (7) is driven by the engine. The drive tang is attached to a shaft which turns the alternator's rotor (3). Rotation of the rotor causes rotation of speed reduction gears (5) and rotating timer (9). The power from the alternator charges storage capacitor (8). There is a separate pickup coil (6) and a separate silicon controlled rectifier (SCR) (10) for each cylinder. As the rotating timer passes over the pickup coils, a pulse from each coil activates each corresponding SCR in sequence. Each SCR releases the energy that is stored in capacitor (8). This energy leaves the magneto through output connector (11) and the ignition wiring harness to the ignition transformers. The transformers increase the voltage to the level that is needed to fire the spark plugs.Wiring Diagram
For your engine's specific wiring diagram, refer to the schematic in the engine mounted junction box.
Illustration 3 g00737733
Wiring diagram for the G3406 Engine ignition system (magneto)