Kubota SM-E4B Series Workshop Manual page 134

SM-E4B SERIES, WSM
Commutator and Mica
1. Check the contact of the commutator for wear, and grind the
commutator with emery paper if it is slightly worn.
2. Measure the commutator O.D. with an outside micrometer at
several points.
3. If the minimum O.D. is less than the allowable limit, replace the
armature.
4. If the difference of the O.D.'s exceeds the allowable limit, correct
the commutator on a lathe to the factory specification.
5. Measure the mica undercut.
6. If the undercut is less than the allowable limit, correct it with a
saw blade and chamfer the segment edges.
Factory
specifica-
tion
Commutator
O.D.
Allowable
limit
Factory
specifica-
tion
Difference of
O.D.'s
Allowable
limit
Factory specification
Mica under cut
Allowable limit
(1) Segment
(2) Depth of Mica
(3) Mica
Brush Wear
1. If the connect face of the brush is dirty or dusty, clean it with
emery paper.
2. Measure the brush length (A) with vernier caliper.
3. If the length is than the allowable limit, replace the yoke
assembly and brush holder.
Factory
specifica-
tion
Brush length
(A)
Allowable
limit
1-S70
Electromagnetic 28.0 mm
drive type 1.10 in.
Planetary gear 30.0 mm
reduction type 1.18 in.
Electromagnetic 27.0 mm
drive type 1.06 in.
Planetary gear 29.0 mm
reduction type 1.14 in.
Less than
Electromagnetic
0.05 mm
drive type
0.002 in.
Less than
Planetary gear
0.02 mm
reduction type
0.0008 in.
Electromagnetic 0.40 mm
drive type 0.016 in.
Planetary gear 0.05 mm
reduction type 0.002 in.
0.50 to 0.80 mm
0.020 to 0.031 in.
0.20 mm
0.0079 in.
(a) Correct
(b) Incorrect
9Y1210785ENS0102US0
Electromagnetic 16.0 mm
drive type 0.630 in.
Planetary gear 14.0 mm
reduction type 0.551 in.
Electromagnetic 10.5 mm
drive type 0.413 in.
Planetary gear 9.0 mm
reduction type 0.35 in.
9Y1210785ENS0103US0
ENGINE
KiSC issued 01, 2013 A