volts per coil connected in series, to
Bake armature as follows:
Vacuum impregnate until bubbling ceases.
Bake in 300°F (149°C) oven for 8 hours.
Type epoxy class F.
11-15. FRAME AND STATOR COMBINATION. The
generator stator is installed in the frame. Eyebolts on the
top of the frame provide a means of lifting. The stator is
mounted in an endbell positioned on the stator frame.
Inspect stator frame for cracks and burred
Inspect stator of generator for loose, frayed,
or burned windings.
Inspect for missing or defective hardware.
Test. Disconnect all leads to completely isolate
Measure each of the six stator windings
with a Kelvin double bridge. Resistance
shall be 1.691 to 1.725 ohms in each
Connect all stator leads together and
measure between the leads and the
generator frame with a megger. To test
insulation resistance, use a megohmmeter
to measure the resistance between a
winding and ground. The insulation
resistance of each of the windings should
be at least 1 megohm at 77°F (25°C). If
this value is not met, clean or dry out the
winding and repeat the test. Replace if
Low insulation resistance may be caused by
dirt or excessive moisture. Insulation failure
may be caused by wrong voltages, induced
voltages caused by opening field circuits
too quickly, oil and grease, high
temperatures, or excessive vibration.
Perform the following stator winding short
Use an outside-type growler, and test
each coil in the stator. Position the
growler in the stator and hold a thin
metal strip, similar to a hacksaw
blade, parallel to the core slots.
Energize the growler and explore the
core surfaces approximately one pole
distance on each side of the growler.
Continue testing one core slot at a
time until all coils are tested. If the
winding is shorted, the metal strip will
vibrate when held over the slot
containing the faulty coil.
If the above test is not met, proceed
with repair procedure.
Replacement. The generator stator core is not to
be removed from the stator frame because the
between bore and rabbit fits
would be disturbed and cause voltage modulation
Repair frayed insulation on leads connected
to the stator windings by covering with tape
Replace eyebolts if defective.