Robin America EY15-3, Руководство по обслуживанию

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Fig. 8-1
8. MAGNETO
8-1 FEATURES
Ignition system of the model EY15-3 and EY20-3 is a maintenance-free electronic pointless magneto
system.
The electronic circuit is based on the cut off of the electric current by power transistor, and employs
U.T.C.I. (Universal Transistor Control Ignition) circuit which always controls the ignition voltage to maxi-
mum.
Thanks to the U.T.C.I., the ignition performance is always stable against environmental changes such as
temperature, etc..
8-2 BASIC PRINCIPLE OF U.T.C.I.
ROBIN electronic ignition system consists of the
ignition coil with built-in U.T.C.I. circuit and the fly-
wheel magnet.
(1) When the flywheel rotates and the magnet
passes the ignition coil, magnetic flux changes
to induce voltage across the primary ignition
coil.
Resultant electric current in the primary coil
is switched by power transistor in the circuit.
(2) When the flywheel rotates further to the igni-
tion timing, ignition timing detection circuit is
activated to turn on the thyristor which cut off
the current to the power transistor suddenly.
The U.T.C.I. controls to cut off the current in-
duced in the primary always at around the
maximum level.
(3) Sudden cut off of primary current induces a
high voltage across the secondary coil to
spark the spark plug.
Fig. 8-2
Secondary Coil
Spark Plug
Primary Coil
Stop Switch
Thyristor
Power transistor
Spark Plug
BLACK
Ignition Coil
Flywheel
Oil Sensor
Stop Switch
Ignition timing
detection circuit