
SEBU8088-06 115
Maintenance Section
Rotating Rectifier-Check
Personal injury can result from air pressure.
Personal injury can result without following prop-
er procedure. When using pressure air, wear a pro-
tective face shield and protective clothing.
The maximum air pressure for cleaning purposes
must be reduced to 205 kPa (30 psi) when the air
nozzleisdeadheaded.
Pressurized air is the preferred method for removing
loose debris. Direct the air in the opposite direction
of the fan’s air flow. Hold the nozzle approximately
6 mm (0.25 inch) away from the fins. Slowly move the
air nozzle in a direction that is parallel with the tubes.
This will remove debris that is between the tubes.
Pressurized water may also be used for cleaning.
The maximum water pressure for cleaning purposes
must be less than 275 kPa (40 psi). Use pressurized
water in order to soften mud. C lean the core from
both sides.
Use a degreaser and steam for removal of oil and
grease. Clean both sides of the core. Wash the core
with detergent and hot water. Thoroughly rinse the
core with clean water.
After cleaning, start the engine and accelerate the
engine to high idle rpm. This will help in the removal
of debris and d rying of the core. Stop the engine.
Use a light bulb behind the core in order to inspect
the core for cleanliness. Repeat the cleaning, if
necessary.
Inspect the fins for damage. Bent fins may be opened
with a “comb”. Inspect these items for good condition:
welds, mounting brackets, air lines, connections,
clamps, and seals. Make repairs, if necessary.
For more detailed information on cleaning and
inspection, refer to Special Publication, SEBD0518,
“Know Your Cooling System”.
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Rotating Rectifier - Check
SMCS Code: 4465-535
Check th
e exciter armature. Ensure that the rotating
rectifier is tight. If a failure of a rectifier is suspected,
proceed to the “Testing a Three-Diode Rectifier
Block”
section.
Testing a Three-Diode Rectifier
Block
g00610240
Illustration 70
g00613971
Illustration 71
Three-Diode Rectifier Block (two pieces)
The following procedure tests all three diodes within
a block. Check the positive rectifier block and the
negative rectifier block. If any meter reading does not
fall within the given ranges, replace the rectifier block.
1. Set the digital multimeter on the diode range.
Remove all leads from the rectifier block.
2. To test the negative rectifier block, follow these
steps: