Rolls-Royce Corniche - Checking Brush Spring Tension; Commutator-To Skim; Generator-To Overhaul, to Dismantle; Method of Undercutting Insulators

Rolls- Royce Silver Shadow B Bentley T Series
Workshop Manu@/
Chapter M
Generator-To overhaul
1.
Release the screw on the band cover and slitle
the cover clear of the brush apertures in the casing.
2. Check the brush spring tension. The tension
should be between 510
g. and 850 g. (18 oz and
SO
OZ) both measurements being obtained radially
to the commutator.
(See Fig. M41).
3.
Remove the brushes from their boxes and
examine the commutator. Discolouration of the com-
mutator may be removed by means of a clean
lint-
free cloth soaked in petrol or methylated spirits. If
this is unsuccessful, insert a strip of fine glass
paper through one of the apertures around the
commutator and back through the same aperture.
Hold the glass paper taut and rotate the commutator
in its normal direction (clockwise, viewed from
driving end). On no account clean an individual
segment as this will produce
' flats' and induce
burning when the generator is operating.
4.
Remove all traces of abrasive dust.
5. Should the commutator be badly burned, worn
or pitted, it should be skimmed on a lathe as
described in Commutator
- To skim.
Generator-To dismantle
(see Fig. M38)
1. Remove the nut and spring washer from the
armature shaft.
2.
Using the special extractor (RH 7098) withdraw
the pulley from the shaft and remove the locating key
from its keyway.
3.
Unscrew and remove the two ' through' bolts
from the casing.
4. Remove the commutator-end bracket from the
generator casing.
5. Remove the drive-end bracket complete with
armature from the casing.
Commutator-To skim
1. Mount the armature in a lathe.
2.
Rotate the armature at a hiah speed and take a
FIG. M41 CHECKING BRUSH SPRING TENSION
1 Spring balance 2 Brush spring
- -
light cut with a very sharp tool. Do not remove more
metal than is necessary.
3.
Remove the armature from the lathe. Under-cut
the insulators between the segments to a deuth of
FIG. M42 METHOD OF UNDERCUTTING
-
0,79 mm. ( +in.) using a hack-saw blade ground to
the thickness of the insulator
(sre Ftg. M42).
INSULATORS
4: Polish the commutator with very fine glass 1 insulators
2 Segments
paper. A Correct method B Incorrect method