Kubota D650-B Handbuch Seite 228

" Staining or Burning of Commutator
1) Check to see if the commutator surface is stained or
burnt.
21
If it is locally burnt, correct with fine sandpaper.
o
Checking Mica (Undercut)
1) Check to see if the mica has sunk below the allowable
limit.
21
If it is below the allowable limit. correct with a saw blade.
Since the correction produces burrs on the corner of the
segment, chamfering should be executed.
III Bad
14) Segment
(2) Good
(5) Depth of mica
C022F058
131
Mica
0.50 to 0.80 mm
• 0.0197 to 0.0315 in.
-----+-------- -------- -_. ­
Allnwl'lhl"
limit
I
less than 0.20 mm (0.0079 mm in.)
._. ­
8
Checking for Field Coil Breakage
11
To check conduction, place the tester probes on the
lead and brush.
2) If not conducting, replace.
(!)
Checking Insulation between Field Coil and Yoke
1) Place each tester probe on the field coil and yoke.
21
If conducting, replace.
Reference value
it is not conducting, the insulation is good; if it is
the insulation is defective.
232