Section C - Electrics
Service Procedures
Alternator
C - 10 C - 10
9803-9450-1
Alternator
TC-006
General Description
The alternator is a three phase generator having a rotating
field winding and static power windings.
When the start switch is turned on, current from the battery
flows by way of the 'No Charge' warning light to the field
winding. This creates a magnetic field which supplements
the residual magnetism in the rotor poles. As the engine is
started, the fan belt drives the rotor and alternating current
is generated in the power windings as they are cut by the
rotating magnetic field. Output is controlled by a solid state
regulator which varies the field current in accordance with
electrical demand.
Servicing is restricted to periodic inspection of slip ring
brushes. Bearings are 'sealed for life'.
Service Precautions
1 Ensure that the battery negative terminal is
connected to the earthing cable.
2 Never make or break connections to the battery or
alternator, or any part of the charging circuit whilst the
engine is running. Disregarding this instruction will
result in damage to the regulator or rectifying diodes.
3 Main output cables are 'live' even when the engine is
not running. Take care not to earth connectors in the
moulded plug if it is removed from the alternator.
4 During arc welding on the machine, protect the
alternator by removing the moulded plug (or if
separate output cables fitted, remove the cables).
5 If slave starting is necessary, connect the second
battery in parallel without disconnecting the vehicle
battery from the charging circuit. The slave battery
may then be safely removed after a start has been
obtained. Take care to connect batteries positive to
positive, negative to negative.
Charging Circuit Test
1 Ensure that all battery and alternator connections are
in place, secure and making good metal - to - metal
contact, especially the 'earth' connections to chassis
and engine.
2 Adjust the alternator drive belt tension if necessary
and make sure that the battery is well charged.
3 Turn the start switch to the ON position.
'Oil pressure' and 'No charge' warning lights should
glow. If any light fails, K
Check 1 ( T C-10).
4 Start the engine; all warning lights should extinguish
rapidly.
If the 'No charge' warning light remains ON, K
Check
2 ( T C-11).
If the oil pressure warning remains on stop engine
Immediately and investigate the engine lubrication
system.
Check 1
With start switch 'ON' try the heater motor and screen
wiper.
If they operate normally, check the warning light bulb for
blown filament.
Simultaneous failure of all items indicates a fault at the
start switch. Check for cable disconnection before
condemning the switch itself.
If the 'No charge' warning bulb is in good order, withdraw
the triple plug from the back of the alternator. Make a
temporary connection between the SMALL terminal in the
plug and earth as shown below. If the 'No charge' warning
bulb still fails to light, check the cable for continuity. If the
bulb now lights, check the alternator for a defective
regulator. K
Alternator Charging Test ( T C-11).
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