GMC 1976 ZEO 6083 Maintenance Manual page 719

24C- 4 2 ONAN MOTOR GENERATOR
TOP VIEW OF
BRUSH BLOCK
CROSS SECTION OF
BRUSH BLOCK
MAXIMUM WEAR LIMIT
ONE INCH
REPLACE WH EN WORN
- TO THIS DIMENSION
OR IF MEASUREMENT
''A'' EXCEEDS ONE INCH
NOTE : MEASURE FROM TOP FACE OF
BRUSH BLOCK TO TOP OF BRUSH .
A-1658
Note that brush blocks are stamped "BRG
END" on one side . Be sure this stamped side faces
bearing end of generator for correct brush alignment.
Tighten the brush block screws to 40 - 70 in-lb. (4-6
ft-lb.) If some sparking occurs after replacing
brushes, run the plant with a light load until brushes
seat properly . Check brush springs for freedom of
movement .
tor .
GENERATOR DISASSEMBLY
(FIGURE 82)
1 . Remove power plant from its slide rails.
2 . Remove all accessories attached to the genera-
3. Tag "and remove all leads.
4. Loosen and lift out both brush rigs .
5. Remove four generator through-stud nuts .
6. Lift or pull end bell from frame assembly . Do
not pry loose with a screwdriver, use a plastic ham-
mer and tap around edges of end bell to loosen .
7. Remove frame (field) assembly, being careful
not to let it rest or drag on the armature .
CAUTION : Four seals are used between
frame (field) assembly and engine-togener-
Figure 81-Brush Wear Limits
ator adapter. These seals must be installed
when reassembling generator or the genera-
tor will overheat.
8. Using a square 3/8-inch drive, insert into 12-
point (internal wrenching) armature hold-down nut
and remove .
9. While pulling outward with one hand under
the armature, strike a sharp end-wise blow on arma-
ture shaft to loosen armature . The armature has an
internal taper which fits onto the external taper of
engine adapter. If the armature does not come loose,
place a heavy brass rod on the armature shaft near
the ball bearing and strike a sharp downward blow
on the rod with a hammer . Rotate the armature 1/2
turn before repeating.
CAUTION : Do not strike the collector rings
or bearing.
GENERATOR TESTING AND
REPAIR
ARMATURE GROUND TEST
Use a 120-volt series test lamp set for this test .
Armature must be removed from generator for this
test .
Place one test prod on one of the collector rings
and the other test prod on the armature shaft. Test
lamp should not light. If the test lamp lights, the AC