Electric System Operation And Function - Robin America EH63 Service Manual

8. ELECTRIC SYSTEM
OPERATION AND FUNCTION
The ignition system is pointless flywheel magneto with automatic advancing characteristic.
Being different from the breaker point type ignition system, this system is completely free from such troubles as
starting-up failure owing to dirty, burnt or corroded point surface.
The electronic automatic advancing ensures extremely easy starts and stable high performance at operating
speed by advancing the ignition timing to the most suitable point.
Low Speed
I
3
Ignition
Timing
Control Circuit
BASIC THEORY
(1) Revolution of the flywheel generates electricity on the primary side of the ignition coil, and the base current
I flows to the power transistor. Current I
1
(2) At lower engine revolution, when the flywheel reached the ignition point the low speed ignition timing control
circuit operates to run the base current I
bypass as current I
4
At this moment the power transistor turns "OFF" and the current I
voltage generated in the secondary coil which produces sparks at the spark plug.
Automatic
Advancing
Control
Circuit
I
4
( B.T.D.C. )
turns the power transistor "ON" and the electric current I
1
3
.
I
1
I
5
I
6
ELECTRONIC ADVANCING FLYWHEEL
MAGNETO SYSTEM
STEP ADVANCING
500 1000
ENGINE REVOLUTION
to turn the signal transistor A "ON" allowing the current I
– 57 –
I
2
2000 3000 (r.p.m.)
is abruptly shut resulting in the high
2
flows.
2
to
1