(11) Inspect the slip rings for cracks, wear
fumes and prolonged exposure of skin to
grooves, damaged or loose lead connections, or other
Wash exposed skin
damage. You can restore a smooth surface to the slip
Dry cleaning solvent (fed.
rings with fine crocus cloth. Wipe all residue from slip
spec. P-D-680) used to clean parts is
rings. Replace the slip rings if they are too worn to be
potentially dangerous to personnel and
property. Do not use near open flame or
excessive heat. Flash point of solvent is
(12) Inspect the rotor bearings for wear,
100 to 138 F (38 to 59 C).
catching or binding operation, or missing or damaged
seals. Replace the bearings if defective. While the
(2) Use a cloth dampened with cleaning
bearings are off the rotor shaft, you should inspect the
solvent (fed. spec. P-D-680) to clean the diode
shaft bearing surfaces for wear.
assemblies, stator, and rotor. Wipe dry.
(13) Inspect the rotor shaft and body for
(3) Wipe the bearings with a cloth, taking
stripped threads, worn key slot, cracked or marred pole
care that you do not disturb the bearing seals.
fingers and shaft. Replace a damaged rotor.
(4) Clean all remaining parts with cleaning
(14) Inspect all other parts for cracks,
solvent; dry thoroughly.
distortion, or damaged threads. Replace all damaged
(5) Inspect and test the brush assembly as
directed in sub-paragraph b above.
(6) Inspect the pulley for cracks, groove
wear, and damage to the keyway. Replace a damaged
Use only rosin core solder to solder diodes
to the stator leads. If you use acid core
(7) Check the fan for bent or missing fins
solder, the connection will corrode,
and mounting hole wear. Replace if damaged.
resulting in an open circuit and damage to
(8) Inspect all insulating sleeves and
washers for cracks, separations and other damage.
(1) Test the diodes with a diode tester
Replace as necessary.
according to the instructions of the equipment
manufacturer. To test, it will be necessary for you to
(9) Inspect the front and rear housings for
unsolder the leads from the stems of the positive and
cracks, bearing bore wear, distortion, damaged threads,
negative diode assemblies for individual testing. When
and other obvious damage. You should remove any
you solder and unsolder leads from the diodes, use long
burrs with a fine stone or file. Replace either housing if
nose pliers to grasp the diode stem between the diode
and the stator lead to be removed. This will give better
heat dissipation and protect the diode from damage.
(10) Inspect the stator for gouged or
You should make note of the diode to stator lead
Discoloration of the winding
connections to facilitate reassembly. If one diode is
insulation is an indication of an overheated stator that
bad, you must replace the entire diode assembly. The
may result in shorted or grounded windings.
positive diode assembly has red printing on the diode
body; the negative diode assembly has black printing.
Refer to figure 3-9.