_I__~
751.2.5130.810
MAGNET
AT 5”
BTDC
CRANKSHAFT
AT
25”
BTDC
751.2.5130.812
Electronic components are very small, have no
moving parts, require no mechanical adjustments,
and are not affected by wear as are mechanical
devices. They deliver uniform performance
throughout component life under adverse operating
conditions. They can be hermetically sealed
so
that
they are unaffected by dust, dirt, oil
or
moisture.
The Capacitive Discharge (CD) system is
breakerless, and contains electronic components
that replace mechanical points and related
accessories (such as a breaker cam, spark advance
assembly, etc.).
Operation
As the flywheel magnet passes the CD pack, an AC
voltage is induced into the charge coil. This AC
voltage
is
converted by a rectifier into a DC signal
which is then stored in a capacitor.
When the SCR is triggered or “fires”, up to
200
volts
DC, stored in the capacitor, travels to the spark coil.
Here
it
is stepped up to as much as
25,000
volts and
is discharged across the electrodes of the spark
Plug-
At slower speeds, the flywheel magnet induces a
smaller charge
in
the trigger coil. This action
triggers the SCR, enabling easier starting
in
a
“retarded firing position” about
5
degrees before top
dead center (BTDC).
At faster speeds (about
800
RPM),
the flywheel
magnets induce a large enough charge in the trigger
coil to trigger the SCR in the “advanced firing
position” (about
25
degrees BTDC).
Service
Section
7-5
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