TM 5-4310-343-35
undercut. Remove all burns and feather edge mica
k.
To remove positive brush holders (35) from
before polishing commutator with No. 000 sandpaper.
bearing
bracket (56) remove two screws (92) and flat
DO NOT USE EMERY.
washer
(94). To remove negative brush holders (35)
remove
two screws (93) and flat washers (95).
5-6.5. Armature(Bogue Electric-Model 6703)
5-6.3. Ball Bearing Check and Replacement (Bogue
a. Cleaning. Remove dust and dirt by blowing out
Electric Model 6703)
with low pressure dry air (25 psi maximum). Inspect
insulation for cracks or breaks and repair if necessary
a. Check the bearing by holding the inner race and
with tape and air-dry insulating varnish.
turning the outer race with the fingers; If it turns hard or
sticks in spots, replace the bearing.
commutator to shaft. If a ground is indicated, it must be
b. Before installing a new bearing, remove all dirt
located and repaired, or replaced with a new armature.
and chips from the bearing shaft seat. Oil the shaft so
that the bearing maybe seated more easily. The bearing
c. Open Circuited. An open circuit in the armature
must be started squarely on the shaft to avoid jamming
is readily detected by the commutator segments which
and scoring the shaft seat. Use and arbor press to force
are badly burned by heavy currents interrupted at the
the new bearing into position Pressure must bear only
open segment. An open circuit in the armature is
against the inner race of the bearing when forcing the
generally due to an overload condition which should be
bearing into place. Never apply pressure against the
investigated. The open usually exists at the soldered
outer race. Wrap a clean cloth around the newly
junction of the coil to the commutator riser. If the
installed bearing to prevent entrance of dust and dirt until
segments are not badly damaged, resolder the affected
final assembly of the motor is completed.
junctions and refinish the commutator as described in a
above. A short circuit in the armature may be detected
5-6.4. Commutator (Bogue Electric Model 6703)
with a growler.
If the commutator is too deeply grooved or pitted to be
5-6.6. Field Coils (Bogue Electric Model 6703)
cleaned with fine sandpaper, the armature must be
mounted in a lathe and the commutator turned down.
The field coils (stator windings) should be checked with
Make sure both center holes are thoroughly dean. Do
a resistance bridge if an open or shorted coil is
not cut deeper than necessary to obtain a smooth
suspected. The total resistance of the series connected
surface. Minimum diameter to which the commutator
field coils plus leads should be 0.029 ohms 20%.
may be turned is 1 7/8 inches, maximum eccentricity of
Examine insulation carefully, tape and varnish any
.001 inch total indicator reading. After turning, the mica
breaks.
segment separators should be undercut to a depth of
1/32 to 3/64 inch. Be certain mica is removed by
5-12A
