11-6. PERMANENT MAGNET STATOR AND FRAME
General. The permanent magnet generator
(PMG) stator furnishes power to the voltage
regulator. The stator (33, figure 11-3) is
bolted to the end-bell (85). It consists of
armature windings in a laminated core
welded to a steel frame. The revolving field
or rotor (37) is made up of permanent
Inspection. Inspect assembly for:
Cracked insulation of wiring.
Accumulation of dust, moisture or
other foreign matter.
Cracks or breaks in welded steel
Test. A resistance check of the stator
winding can be made as follows:
Connect a Wheatstone bridge to the
Resistance should be 0.0024355
ohms per winding, at an ambient
temperature of 77°F (25°C).
If resistance reading is incorrect,
replace defective stator assembly.
Replacement. When disassembling the
PMG stator from the generator, the PMG
rotor and exciter assembly is also removed.
Removal. Remove as follows:
(a) Remove screws (26 and 28,
figure 11-3), washer (29), and nut
(27), and remove cover (30).
USE EXTREME CARE WHEN REMOVING
ROTOR TO PREVENT INJURY TO HANDS
BETWEEN THE PMG ROTOR AND THE PMG
Take out retaining bolt (34) and washer (35).
Observe WARNING above, and remove pin (36)
and PMG rotor (37).
If the PMG rotor is to remain disassembled
for an extended period, install a keeper on
the rotor. Use a band of iron or steel.
Support the PMG stator with an overhead crane
OVERHEAD OPERATIONS HAVE INHERENT
HAZARDS THAT CANNOT BE
MECHANICALLY SAFEGUARDED. HARD
HATS AND SAFETY SHOES ARE REQUIRED.
Disconnect the PMG stator leads. Tag leads for
Disconnect and tag exciter field leads.
Remove exciter rotor (38) as follows:
Remove set screw (52).
The exciter armature is a "slip-fit" on the
generator shaft. If the armature cannot be
removed by hand, remove with a puller.
Do not pull on rotating rectifier
assembly of the exciter armature
Install a cap or plug to protect the shaft center.
Using the tapped holes in the end of sleeve, bolt to
the end of sleeve spacers and a metal plate. Refer
to figure 11-11.
Hook a bearing puller to the metal plate and pull
exciter armature and rotating rectifier assembly
from the shaft.