Electric System; General; Function Of The Ignition Unit - Rotax 447 UL SCDI Installation Manual

18)

Electric system

18.1)
18.2)
Effectivity: 447 UL SCDI, 503 UL DCDI, 582 UL DCDI /mod. 99
AIRCRAFT ENGINES
INSTALLATION MANUAL

General:

The engine is equipped with a breakerless 12V 170W DUCATI capacitor-
discharge dual ignition system (447 UL SCDI is only equipped with a single
ignition unit). It consists of a flywheel magneto generator, 2 double ignition
coils complete with integrated control-circuit and 2 external trigger coils
(pick-up).
The 12-pole flywheel generator is an outer rotor type with 12 integrated
permanent magnets. The stator is equipped with 12 coils. 8 of them are
used for feeding auxiliary equipment and 4 are used for the dual ignition.
The grey cable is foreseen for connection of a revolution counter.

Function of the ignition unit:

Two charging coils fitted on the generator stator and independant from
each other each feed one ignition circuit. The energy supplied is stored in
the ignition capacitor. At the moment of ignition the external trigger coils
supply an impulse to the control circuits and the ignition capacitors are
discharged via the primary winding of the ignition coil. The secondary
winding supplies the high voltage for the ignition spark.
■ ATTENTION: When flying both ignition systems must be switched ON.
page 18 - 1
Initial issue, May 01/99