Generator Coil; Resistance Values Of The Ignition Unit - Rotax 912 Series Maintenance Manual

13.4.6)
13.4.7)
Effectivity: 912 Series
AIRCRAFT ENGINES
MAINTENANCE MANUAL II

Generator coil

See fig. 094.
If the generator does not work, the reason may be a defective or squeezed
yellow generator cable or a defective winding on the 8 generator coils E
(see fig. 094). Disconnect generator cables (yellow) and check resistance
values, see para 13.4.7. There must be no connection between yellow
cable and ground, and the indication on the ohmmeter must be ∞. If the
value measured corresponds with the values indicated, the cause may be
a defective rectifier-regulator.
Check of the complete ignition unit is only possible on an ignition test bench
with an oscilloscope, see para 11.5. Especially if the failure occurs only
occasionally this is necessary. In this case send the complete ignition unit
to an authorized overhaul facility, see Maintenance Manual 912 Series
(Line Maintenance ) Chapter 05-00-00 para 2.2.
CAUTION: On all these works pay special attention that no foreign
matter will enter the ignition.

Resistance values of the ignition unit

The values indicated below can be checked on the engine installed in the
aircraft, after detaching connections:
Generator coil (on stator) .................. yellow – yellow ............ 0,1 ÷
Generator winding ............................. yellow – grounding ..... ∞
Charging coil (on stator) ......................... red – ground ........... 3,2 ÷
Trigger coil ................................ green/white – blue/yellow .. 15,0 ÷ 123,0 Ω
Trigger coil new* (with clamps) white/yellow – blue/yellow 240,0 ÷ 250,0 Ω
Ignition coil, primary ..... connection contact – ground ........... 0,1 ÷
Ignition coil, secondary ............ high voltage – high voltage ... 6,1 ÷ 6,7 kΩ
Resistance spark plug connector ...............
NOTE: * Fitted in serial production, starting with design year
1995!
0,8 Ω
4,5 Ω
0,4 Ω
...................... 4,4 ÷ 6,0 kΩ
page 64
Initial issue, Jan. 01/2002