Norton Commando Workshop Manual

## Electrical

# J

### SECTION J1

### DESCRIPTION

The Commando electrical system is grouped into four areas for the purpose of this manual. The areas are:
Sections J2 to J8: | Those parts connected with the charging system.
Sections J9 to J14: | Those parts connected with the ignition system.
Sections J15 to J19: | Those parts connected with the lighting system.
Sections J20 to J28: | Other electrical equipment.

### IMPORTANT

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.
The Commando electrical system is positive earth (ground).

### SECTION J2

### CHARGING SYSTEM

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.
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.
Below are detailed the components of the charging system with applicable test procedures:

### SECTION J3

### ALTERNATOR - LUCAS TYPE RM21

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.
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.

### Maintenance

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.

### Testing the alternator in situ

(a) | Disconnect the alternator leads at the snap connectors.
(b) | 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.
(c) | Start engine and run at approx. 3,000 rev./min. noting voltmeter readings.

VOLTMETER AND RESISTOR ACROSS | MINIMUM VOLTAGE READINGS
Stator: Two lead
Type: RM21
White/Green. Green/Yellow | 9
Any one lead and stator earth (ground) | NO READING

### CONCLUSIONS:

If the reading is low, check the rotor by substitution. Zero reading indicates open-circuited coil(s).

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