Komatsu 830E-AC Shop Manual page 203

Interpreting Results of Tests
1. Rated current draw and no-load speed indi-
cates normal condition of the cranking motor.
2. Low free speed and high current draw indi-
cates:
a. Too much friction; tight, dirty, or worn bear-
ings, bent armature shaft or loose pole
shoes allowing armature to drag.
b. Shorted armature. This can be further
checked on a growler after disassembly.
c. Grounded armature or fields. Check Further
after disassembly.
3. Failure to operate with high current draw indi-
cates:
a. A direct ground in the terminal or fields.
b. "Frozen" bearings (this should have been
determined by turning the armature by
hand).
4. Failure to operate with no current draw indi-
cates:
a. Open field circuit. This can be checked after
disassembly by inspecting internal connec-
tions and tracing circuit with a test lamp.
b. Open armature coils. Inspect the commuta-
tor for badly burned bars after disassembly.
c. Broken brush springs, worn brushes, high
insulation between the commutator bars or
other causes which would prevent good con-
tact between the brushes and commutator.
5. Low no-load speed and low current draw indi-
cates:
a. High internal resistance due to poor connec-
tions, defective leads, dirty commutator and
causes listed under Number 4.
6. High free speed and high current draw indicates
shorted fields. If shorted fields are suspected,
replace the field coil assembly and check for
improved performance.
D02034
Disassembly
The cranking motor should be disassembled only as
far as necessary to repair or replace defective parts.
1. Note the relative position of the solenoid (53,
Figure 2-6), lever housing (78), nose housing
(69), and C.E. frame (1) so the motor can be
reassembled in the same manner.
2. Disconnect field coil connector (42) from sole-
noid motor terminal, and lead from solenoid
ground terminal.
3. Remove the brush inspection plug (52), and
brush lead screws (15).
4. Remove the attaching bolts (34) and separate
the commutator end frame (1) from the field
frame (35).
5. Separate the nose housing (69) and field frame
(35) from lever housing (78) by removing
attaching bolts (70).
6. Remove armature (45) and drive assembly (71)
from lever housing (78).
7. Separate solenoid (53) from lever housing by
pulling apart.
24 VDC Electric Supply System D2-13