Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual

Page: 323 / 413

WSM.124
Section N (Elec. Equip.)
Armature
Indication of an open-circuited armature winding
will be given by burnt commutator segments. If
armature testing facilities are not available, an
armature can be checked by substitution.
To separate the armature shaft from the drive-end
bracket, press the shaft out of the drive-end bracket
bearing. When fitting the new armature, support
the Inner journal of the ball bearing, using a mild
steel tube of suitable diameter, whilst pressing the
armature shaft firmly home (See also "To re­
assemble", page 10).
Field Coils
Measure the resistance of the field coils, without
removing them from the generator yoke, by means
of an ohm meter connected between the field
terminal and the yoke.
Field resistance is 5·9 ohms.
If an ohm meter is not available, connect a 12-volt
d.c. supply between the field terminal and generator
yoke with an ammeter in series. The reading should
be approximately 2 amperes. Zero reading on the
ammeter or an "Infinity" ohm. meter reading
indicates an open circuit in the field winding.
If the current reading Is much more than 2 amperes,
or the ohm meter reading much below 5·9 ohms, it is
an indication that the insulation of one of the field
coils has broken down.
In either event, unless a replacement generator is
available, the field coils must be replaced. To do
this, carry out the procedure outlined below:-
1. Drill out the rivet securing the field coil
terminal assembly to the yoke, and remove the
insulated sleeve from the terminal blade to
protect it from the heat of soldering.
2. Unsolder the terminal blade and earthing eyelet.
3. Remove the insulation piece which Is provided
to prevent the junction of the field coils from
contacting with the yoke.
4. Mark the yoke and pole shoes so that the
latter can be fitted In their original positions.
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Page 9
5. Unscrew the two pole shoe retaining screws
by means of a wheel-operated screwdriver
(See Fig. 7).
6. Draw the pole shoes and coils out of the yoke
and lift off the coils.
Fig. 7.
Unscrewing pole retaining screws
7. Fit the new field coils over the pole shoes and
place them in position Inside the yoke. Take
care to ensure that the taping of the field coils
is not trapped between the pole shoes and the
yoke.
8. Locate the pole shoes and field coils by lightly
tightening the fixing screws.
9. Fully tighten the screws by means of the
wheel-operated screwdriver.
10. Solder the terminal blade and earthing eyelet
to the appropriate coll ends.
11. Refit the Insulating sleeve and re-rivet the
terminal assembly to the yoke.
12. Refit the insulation piece behind the junction
of the two coils.
Bearings
Bearings which are worn to such an extent that they
will allow side movement of the armature shaft,
must be renewed.