1948-1952 Shop Service Manual - - Hudson-Essex-Terraplane Club

ELECTRICAL SYSTEM 6 - 11
6. Remove drive pulley and Woodruff key.
7. Remove armature from drive head end.
8. Remove bearing retainer screws and remove retainer, felt
washers, gasket and bearing.
NOTE: The following generator checks, pages 6-11 to
6-16 can be made on a suitable test stand by an experienced
operator.
FIELD COIL GROUND TESTS:
1. Make sure no leads are touching frame.
2. Using a set of test probes in series with a lamp and a
source of electricity, touch one probe to the field terminal
stud and ground the other probe to the generator frame.
3. If lamp lights, coils are grounded.
4. If ground is present, remove nuts and washers from
armature and field terminals and
press terminals from frame.
5. Repeat ground test. If lamp does not light on this test,
faulty terminal post insulation is indicated.
6. If coils still test grounded, unsolder connection between
coils.
FIELD COIL OPEN CIRCUIT TEST:
1. Touch one test probe to armature terminal stud and one
to field terminal stud.
2. If lamp does not light, an open circuit is present.
3. To determine which coil is open, hold one test probe on
the connection between the coils and touch the field coil
terminal and then the armature terminal with the other
probe. If lamp lights, coil on that side is good.
4. Replace open circuited coil.
FIGURE 9
FIELD COIL SHORT CIRCUIT TEST:
1. Connect ammeter, battery and variable resistor in series
with the field coil terminals, (Figure 9).
2. Connect a voltmeter across the terminals.
3. Adjust voltage to 5 volts and read ammeter.
4. If current is not 1.3 to 1.5 amperes, a short exists in the
field coil.
5. If a short is present, check each coil separately and
replace shorted coil.
FIELD COIL REMOVAL:
1. If a field coil tests open, short or grounded, unsolder
connection between the coils and disconnect faulty coil
from terminal post.
2. Mark pole shoe position in frame to assure replacement
in correct position.
3. Remove pole shoe screw. (Use a pole shoe removing tool
if available.)
4. Remove pole shoe and remove coil.