Rolls-Royce Silver Shadow
&
Bentley
T
Series
Workshop
Manual
Alternator-To assemble
Reverse the dismantling procedure, noting the
following points:
a. Ensure that the slip ring bearing is positioned
as far as it will go along the rotor shaft towards
the field assembly.
b. Ensure that the brushes are in the brush housing
before fitting the brush moulding.
c. Tighten the through bolts evenly.
d. If the rotor and drive-end bracket have been
separated, support the inner ring of the drive-end
bearing with the distance collar. Do not use the
drive-end as a support for the bearing when fitting
the rotor.
Alternator Lucas Model
11
AC
Field isolating device
With the engine stationary, the control unit and the
alternator field windings are isolated from the battery
by the normally-open contacts of the Model
6RA
relay, the operating coil of which is fed from the
ignition switch.
The contacts of the relay are connected in the
negative lead of the regulator.
Maintenance
Remove any dirt or oil from around the ventilating
apertures of the slip ring end cover.
Lubrication
The alternator bearings are packed with grease
during assembly and do not require periodic
attention.
Terminal connections
Ensure that all terminal connections are secure.
Alternator-To test in position
A
fault in the charging circuit should be located as
R
z
follows:
6
1.
Examine the alternator driving belts for wear
*P:
I-
and correct tension.
2.
Apply the handbrake and chock the rear wheels.
Start the engine and check to ensure that battery
voltage is being applied to the rotor winding by
connecting a voltmeter between the cable ends nor-
mally attached to the field terminals. Stop the engine.
3.
Disconnect the battery earth lead.
4.
Withdraw the leads from the alternator field
terminals, then using a suitable pair of auxiliary
cables, connect the terminals directly to the battery
0
(see Fig.
dl.23).
Chapter
M
5.
Re-connect the battery earth lead. Start the
engine and slowly open
thr throttle until the engine
speed is approximately
1
650
r.p.m. At this speed
the ammeter should indicate approximately
40
amps.
If
a Zero reading is registered on the ammeter, stop
the engine and disconnect the leads from the field
terminals. Remove the two screws securing the
brushbox moulding and remove the brushgear for
examination
(see Brusllgear
-
To inspect).
Note
When carrying out this operation, on
no account should the engine speed
exceed
2000
r.p.m., or damage to the
diodes will result.
6.
If necessary fit new brush and spring
assemblies and again test the alternator output. If
the Zero reading persists, the alternator must be
removed from the engine and dismantled for detailed
inspection
(see Alternator
-
To dismantle).
A
low output current reading will indicate a
faulty alternator or poor circuit wiring connections.
Check the connections while the alternator is con-
nected and running at
1
650
r.p.m. engine speed.
Connect a low range voltmeter between the alternator
output terminal and the battery insulated terminal
(see
Fig.
M24),
and note the voltmeter reading.
Transfer the voltmeter connections to the
alternator frame and battery earth terminal
(see
Fig.
M25);
note the reading.
If either of these readings exceed
0.5
Volt there
is a high resistance in the charging circuit, this
must be traced and rectified.
If there is no undue
resi,stance in the charging
circuit even though the alternator output is low,
proceed to dismantle the alternator.
Alternator-To remove
1.
Disconnect the alternator electrical
connections.
2.
Slacken the two upper securing bolts (lower
on early cars).
3.
Slacken the setscrew on the slotted adjuster
link.
4.
Move the alternator inwards towards the engine,
in order to release the tension on the driving belt;
remove the belt.
5.
Support the alternator and remove the pre-
viously slackened bolts, taking note of the position
of the spacers to facilitate assembly.
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