Workshop
Manual
Rolls- Royce Silver Shadow
&
Bentley
T
Series
Chapter
M
2.
Remove foreign material from rotor shaft and
stator using a clean cioth moistened with white
spirit.
Caution
Spirit should not be allowed to
contact the leads of the stator and
must not contaminate the protective
coating of the rotor core.
3.
Examine the stator windings for security and
condition. Check the insulation of the stator leads
for deterioration.
4.
Check the bearings for excessive play and
smoothness of operation. The bearings are sealed
and cannot be lubricated therefore any evidence of
dryness will necessitate renewal. If the SRE
bearing requires replacement it will also be
necessary to renew the slip ring.
5.
Examine the slip rings for signs of wear and
scoring. The slip rings may be skimmed to a
minimum diameter of
28,5
mm. (1.136 in.) before
replacement is necessary.
6.
Check carbon brushes for wear. New brushes
are
15,9 rnm. long
(0.625
in.) and the minimum
length of usable brushes is
7,9
mm.
(0.312
in.).
FIG.
M20
BEARING EXTRACTOR
FIG.
M21
RENEWING SLIP RING
CONNECTING LEADS
1
Staggered wire cuts
2
3
mm
sleeving
3
2
mm
sleeving
4
Excess wire removed
Bearing renewal-Drive end
1.
Remove
the three screws and washers securing
the clamp plate and push out the bearings with a
copper drift.
2.
Press a new bearing into the housing, ensuring
that it is perfectly square to the housing.
3.
Place the clamp plate in position and secure
with three screws and washers.
Bearing renewal-Slip ring end
1.
Cut the ends of the field leads free from the
slip ring terminal posts.
2.
Using an extractor
(see
Fig.
12.120)
withdraw
the slip ring assembly. Removal of the slip ring
renders it unserviceable and a new one must be
fitted.
3.
Remove bearing circlip. Adjust the jaws of
bearing extractor so that the jaws locate between
the outer race and the bearing spacer and withdraw
bearing.
4.
Examine bearing spacer for cracks and
distortion. Clean out groove. Renew spacer if
damaged.
5.
Detaching the rotor leads from the slip ring
assembly imposes mechanical stresses that may
weaken the leads and produce the possibility of
failure under operating conditions at a later date.
It is strongly recommended that the leads are
renewed in the following manner
(see
Fig.
M21).
Cut the leads s6 that the subsequent joints are
staggered. Trim back the glass-fibre sleeving and
lightly twist a new length of Lumex copper wire
(21.5 swg) to the existing wire and solder together.
Snip off excess wire. Apply
a
liberal coating of
shellac and slide a short length of
2
mm. glass-
fibre sleeving over the joint so that it slides
0
inside the existing sleeve. Apply a further coating
of shellac and
slide on
a
new length of
3
mm. glass-
fibre sleeving to abutt the original sleeve. Apply a
final coat of shellac to the outside.
6.
Refit the bearing spacer over the rotor shaft
so that the moulded groove is in the correct
position to contain the field leads from the rotor.
Press into position. Press new bearing onto the
rotor shaft with a suitable hand press. Refit the
circlip, ensuring it is fully seated and a tight fit
in its groove. Plug with 'Silcoset' 151 any gap that
appears where the leads enter the spacer between
the spacer and the rotor claws. Wipe off any
surplus
'
Silcoset' 151.
7.
Place the rotor (drive end downwards) in a
hand press so that the weight is supported on the
rotor claws. Pass the two field leads through the
-
bore of a
~cw
blip ring and locate the slip ring to
the shaft with the terminal posts positioned
at
90'
3
relative to the shaft lead slot.
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