At The Higher Engine Speed - Robin EH12 Service Manual

2) At the higher engine speed
Rotation
of the flywheel generates the current I, as
this current
flows through the base terminal of the
power transistor, i t is activated and the current
IZ
starts of flow.
As the engine reaches the ignition timing, the ignition timing control circuit for the higher engine
speed is activated and provides the base current Is to the power transistor. This current induces the
coIlector current
16
and will bypass the current I, to shut down the current I r abruptly because the
power transistor is turned off.
This sudden current change generates a big voltage on the secondary side of the ignition coil and
which will spark the spark plug.
The ignition timing control circuit for the higher engine speed is activated sooner than the control
circuit €or the lower speed and
not activated when the engine speed is in a lower range.
ELECTRONIC ADVANCING FLYWHEEL
MAGNETO SYSTEM
(B.T.D.C.)
L
STEP ADVANCING
1 5 ' 1
,
,
, ,
500
1000 2000 3000(r.p.m.)
ENGINE REVOLUTION
Fig. 6-2 ( b )
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43
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