Replacing the Diodes
Use the manufacture's specified tools, if available,
The rotor must be rotated so the slip rings are
and a press or vise to remove and install the diodes, as
cleaned evenly. Cleaning by hand without
shown in figures 6-30 and 6-31. If the manufacture's
spinning the rotor will result in flat spots that will
tools are not available, suitable substitutes may be used,
cause excessive brush wear and noise. Slip rings
but you must exercise particular care to prevent damage
that are out-of-round, or very rough, must be
to the diodes or the slip ring end frame assembly.
turned in a lathe. Inspect the brushes for excessive
wear. Replace them if they are worn to less than
half the original length.
Do not strike any of the diodes while you are
Bearing Replacement and Lubrication
removing or installing them. The shock may cause
damage to the diode being removed or installed as
Remove the bearing retainer plate and oil seal
well as to others already installed.
assembly and, using suitable adapters, press the bearing
from the drive end frame. Clean the bearing with an
Once you have replaced all the defective diodes,
approved cleaning solvent, and dry it with low-pressure
test them (as previously described) before reassembling
compressed air. Cleaning solvents are toxic and should
the generator. This is to ensure they are still in
be used only in well-ventilated areas.
Inspect the bearing. If it is in satisfactory condition,
it may be reused. However, if while you are turning the
Slip Ring Servicing
bearing by hand, you find rough spots or excessively
worn balls, it must be replaced. If the bearing is to be
If the slip rings are dirty, you may clean and finish
reused, fill it one-quarter full with special grade ball
them with 400-grit polishing paper or crocus cloth.
bearing grease and reinstall it in the drive end frame. If
Spin the rotor, in a lathe if possible, and hold the
the bearing retainer plate's felt oil seal is hardened or
polishing material against the slip rings until they are
excessively worn, the retainer plate and seal assembly
should be replaced.
END FRAME OR
H E AT S I N K
Figure 6-30.--Removing diodes.