TM 5-4520-241-14
KEY to fig. 8-2:
1.
Nut
15.
Field screw
2.
Lockwasher
16.
Frame cap
3.
Suppression capacitor
17.
Loading spring
4.
Motor housing
18.
Nut
5.
Wire
19.
Washer
6.
Wire
20.
Armature
7.
Ty-rap
21.
Field
8.
Butt connector
22.
Ball bearing
9.
Thermal cutout
23.
Housing frame assembly
10.
Wire
24.
Spacer
11.
Screw
25.
Fan assembly
12.
Clamp
26.
Spacer spool
13.
Carbon brush assembly
27.
Upper chamber
14.
Ground strap
28.
Lower chamber
(2) Clean all non-electrical part by immersing in dry cleaning solvent (fed. spec. P-D-680). Wipe thoroughly and
allow to dry.
(3) Inspect the fan assemblies for bent or damaged parts. Replace defective fan assemblies.
(4) Inspec t the motor brushes for cracks, chips, wear, or scoring. Replace worn brushes.
NOTE
Brushes in the combustion motor are designed to last a minimum of 2,000 hours in
operation before replacement.
(5) Inspect the commutator. Replace the armature and bearings if the commutator is scored or badly burned.
Light scoring can be cleaned up with fine sandpaper.
(6) Inspect the suppression capacitors (condensers) for any signs of damage. Replace if damaged. Use a
capacitance tester to check the capacitors. Capacitance should be 0.47 microfarad 10%. If not, replace the capacitors.
(7) Connect the brown and white leads from the capacitors to the terminal strip as shown on the wiring diagram.
Restore power and test the motor.
c. Assembly. Assemble the combustion motor by reversing disassembly sequence. Note the following:
(1) If a new field (21, fig. 8-2) is being installed, carefully inspect the wires (6 and 10) secured to the field winding.
The wires supplied with replacement fields are covered with neoprene insulation, which is not acceptable for this
application. Cut off the wires and splice on nylon-insulated wires of the correct length.
8-6
