Cleaning Disassembled Parts of Travel Motor

TM 10-3930-609-35

c. Check field coils with an ohmmeter for

c. Remove four screws and lockwashers which

continuity. Check that field coils in series have a

secure shunts on brush assemblies to brushholders;

resistance of 0.0366 10 percent ohms at 70 .

then, withdraw brush assemblies from brushholders.

d. Check armature on a growler for shorted and

d. Carefully examine front motor yoke, rear motor

open windings.

yoke and motor ring for match marks. If no match

marks are visible, use a punch or chisel to lightly match

e. Inspect commutator on armature for grooving,

mark these parts.

pitting, scoring and for metallic slivers between

e. Remove four screws and lockwashers which

segments.

secure front motor yoke to motor ring; then, carefully

f. Inspect brush springs for distortion and loss of

remove front motor yoke from motor ring.

tension due to overheating. Check brush springs for

f. Remove screws, washers and insulating

proper tension during reassembly of motor as described

in paragraph 3-89.

bushings which secure brushholders in front yoke; then,

remove brushholders and insulators from front yoke.

g. Inspect brush assemblies for excessive wear

g. Remove

nuts,

lockwashers,

flatwashers,

and for security of shunts and terminals. Check that

brushes slide freely in brushholders without binding or

external insulator and insulating washers from threaded

excessive looseness.

portion of brush connector assemblies; then, remove

brush connector assemblies, insulating washers, internal

h. Inspect brush connector assemblies for frayed

insulator, flatwashers and two-hole insulator from inside

insulation and for damage due to overheating.

front yoke.

i. Inspect brushholders for distortion or other

h. Remove nuts and lockwashers from eight studs

damage.

securing rear yoke to motor ring; then, carefully remove

k. Inspect field coil assembly for frayed wrapping

rear yoke.

and for damage to winding insulation due to

i. Remove retaining ring, rear bearing and oil seal

overheating. Also inspect sleeving on field coil leads for

from rear yoke.

damage.

j. Withdraw armature from motor ring and remove

I. Inspect bearing mounting surfaces on armature

front bearing from armature shaft.

shaft and bearing bores in yokes for scoring, wear or

k. Remove nuts, lockwashers, flatwashers and

other damage due to bearing failure.

insulating washers from stud terminals; then, remove

stud terminals from motor ring and remove insulating

3-88. Repair and Replacement of Travel Motor Parts

bushings, insulating washers and flatwashers from stud

a. Replace all distorted or cracked parts and any

terminals.

parts that have been damaged due to overheating.

l. Remove field coils from motor ring only if

b. Replace oil seal and both ball bearings at each

replacement is required by taking out screws which

reassembly.

secure pole pieces in motor ring.

c. Repair minor damage to field coil wrapping by

rewrapping with glass fiber tape and applying electrical

3-86. Cleaning Disassembled Parts of Travel Motor

insulating varnish to repaired areas.

a. Wash all metallic parts with SD and dry with

d. Replace brush connector assemblies if

compressed air under moderate pressure.

damaged in any way.

b. If field coils have not been removed from motor

e. Replace brush assemblies if worn to less than

ring, blow dust from coils and inside motor ring with

3/4 inch in length or if shunts are damaged.

compressed air.

f. Repair minor thread damage with tap or thread

c. Be sure to clean all parts thoroughly to facilitate

chaser.

inspection.

g. If required, true up commutator on armature by

chucking in a lathe. Do not remove more metal from

3-87. Inspection of Travel Motor Parts

commutator than necessary to produce a smooth, bright,

a. Inspect motor ring and yokes for cracks and

continuous surface on all segments. Minimum allowable

distortion.

diameter of commutator after turning is 2.375 inches.

b. Inspect all threaded parts and tapped holes for

Maximum allowable surface roughness of commutator

stripped threads or other damage.

segments after

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