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ROYAL ENFIELD WORKSHOP MANUAL
terminal "D" to dynamo terminal "D" and
regulator terminal "F" to dynamo terminal "F"
and check the regulator.
4 (b). To Dismantle
Remove the dynamo and distributor from the
motor cycle. To detach the distributor from the
dynamo drive end bracket, loosen the distributor
shank clamping bolt and withdraw the complete
unit from the bracket (see Fig. 1). On earlier
models an additional securing bolt is located in
the drive end bracket and must be loosened a
few turns to allow the distributor to be
withdrawn from the bracket. Proceed to
dismantle as follows :-
(i) Remove the securing nut from the drive
end of the armature shaft and withdraw the
sprocket with the aid of an extractor. Knock out
the key from the armature shaft.
(ii) Unscrew the two commutator end cover
securing screws and remove the cover. Hold
back the brush springs and lift the brushes from
their holders.
(iii) Disconnect the earthed field connection
and unsolder the field connection to terminal
"F" on the terminal strip.
(iv)
Unscrew
commutator end bracket the two through bolts
securing the end bracket and yoke to the drive
end bracket.
(v) Draw the commutator end bracket away
from the armature and separate the yoke from
the drive end bracket. On earlier models a thrust
spring will be found around the armature shaft
(on later models it is located between the ball
bearing and the housing); take care not to lose
this.
(vi) The armature can now be pressed out of
the drive end bearing, taking great care not to
damage the sealing lip of the rubber oil seal.
(vii) Unscrew the two screws on the inner
side of the commutator end bracket which
secure the insulated terminal plate carrying the
terminals and brushgear. On earlier models
removal of the insulating plate will reveal the
bearing retaining plate and thrust spring
housing.
4. (c) Commutator
Examine the commutator. If it is in good
condition, it will be smooth and free from pits or
burnt spots. Clean with a petrol-moistened cloth.
If this is ineffective, carefully polish with a strip
of very fine glass paper while rotating the
armature. To remedy a badly worn commutator,
mount the armature with or without the drive end
bracket in a lathe, rotate at high speed and take a
light cut with a very sharp tool. Do not remove
more metal than is necessary. Polish the
commutator with very fine glass paper.
and
remove
from
Undercut
segments to a depth of 1/32 in. with a hacksaw
blade ground down until it is only slightly
thicker than the insulation (see Fig. 3).
4 (d). Field Coil
Measure the resistance of the field winding
by means of an ohm-meter. If this is not
available, connect a 6-volt D.C. supply with an
ammeter in series with the coil. The ammeter
reading should be approximately 2 amps. No
reading on the ammeter indicates an open circuit
in the field winding.
To check for an earthed coil, connect a
mains test lamp between one end of the coil and
the yoke. If the bulb lights, there is an earth
between coil and yoke.
the
In either case, unless a replacement dynamo
is available, the field coil must be replaced but
this
should
wheel-operated screwdriver and pole shoe
expander are at hand, the latter being especially
necessary to ensure that there will be no air gap
between the pole shoe and the inner face of the
yoke.
To replace the field coil, proceed as follows :
(i) Unscrew the pole shoe retaining screw by
means of the wheel-operated screwdriver (see
Fig. 4).
the
insulation
between
only
be
attempted
Section G2a Page 3
the
if
a
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