SECTION J1
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DESCRIPTION
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The Commando electrical system is grouped into
four areas for the purpose of this manual. The
areas are:
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Sections J2 to J8:
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Those parts connected with the charging system.
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Sections J9 to J14:
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Those parts connected with the ignition system.
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Sections J15 to J19:
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Those parts connected with the lighting system.
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Sections J20 to J28:
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Other electrical equipment.
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IMPORTANT
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Betore starting any electrical test procedures,
on 1971 and later models, isolate the 3 AW warning
light assimilator by disconnecting the green/yellow
lead to the assimilator at the alternator
green/yellow lead double snap connector.
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The Commando electrical system is positive earth
(ground).
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SECTION J2
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CHARGING SYSTEM
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The charging system comprises an alternator with
the 6 charging coils connected permanently, (fitted
in the primary chaincase and driven by the engine
crankshaft). This supplies alternating (A.C.)
current to the rectifier where it is converted to
direct (D.C.) current. The D.C. current is fed to
the lead/acid battery in parallel to the Zener
diode which is mounted on the right support plate
for the silencer and footrests.
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The function of the Zener diode is to regulate
the flow of D.C. current and thus prevent
overcharging of the battery. Surplus current is
directed to the heatsink (in this case, the light
alloy support plate for the right hand silencer and
footrests) where it is dissipated as heat.
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Below are detailed the components of the
charging system with applicable test procedures:
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SECTION J3
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ALTERNATOR - LUCAS TYPE RM21
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The alternator produces an alternating current
(A.C.) by means of a six-pole permanent-magnet
rotor which rotates within a stationary six-pole
laminated-iron stator assembly.
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The rotor is attached to the engine crankshaft,
which revolves at engine speed. The stator
sub-assembly, comprising the windings and
laminations, is attached to the primary chaincase.
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Maintenance
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The alternator and associated equipment requires
no maintenance except for an occasional check to
ensure that all the external cable connections are
clean and E tight. The rectifier securing nut
should make good electrical contact. If it should
be necessary to remove the alternator rotor from
the engine crankshaft, the use of magnetic keepers
is not necessary, but keep the rotor away from
magnetically-attracted metal foreign matter.
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Testing the alternator in situ
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(a)
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Disconnect the alternator leads at the snap
connectors.
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(b)
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Connect an A.C. voltmeter (with 1 ohm resistor
in parallel) as detailed in the table below. See
Section J25 for instructions on making a 1 ohm
resistor.
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(c)
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Start engine and run at approx. 3,000 rev./min.
noting voltmeter readings.
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VOLTMETER AND RESISTOR
ACROSS
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MINIMUM VOLTAGE READINGS
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Stator: Two lead
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Type: RM21
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White/Green. Green/Yellow
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9
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Any one lead and stator earth (ground)
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NO READING
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CONCLUSIONS:
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If the reading is low, check the rotor by
substitution. Zero reading indicates open-circuited
coil(s).
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