Upright TM12, Service & Parts Manual

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Page 3-31
Maintenance
3.17 - Electric Motor
TM12 Work Platform - European
Figure 3-28: Electric Motor Service
R
EASSEMBLY
1. Install new brushes and be sure they are
free in the holder. Install brush with the
lead wires positioned as when received.
Raise all brushes to the locked position.
(See Figure 3-28B and step 3 in the
Inspection section).
2. Place commutator cover on a work bench
with brush assembly facing upward.
3. Place the bearing spring into the bearing
bore.
4. Take a complete armature assembly,
including bearings, and insert commuta-
tor end bearing into the bearing bore.
NOTE: Do not re-use bearings which have been
removed from armature shaft. Keep assembly in a
vertical position. Use extreme care not to damage
armature with bearing pullers. New bearings
should be installed by pressing inner race of
bearing onto proper position on armature shaft.
5. Set the brushes to final position as shown
in Figure 3-28B.
6. Place the complete stator down over the
vertical armature, and into position on the
commutator cover.
7. The stator assembly must be placed in a
definite relationship with the commutator
covers in order to obtain a neutral brush setting. There is a match-mark on both items.
These two marks must line up exactly. Rotate until they do.
8. Assemble the pulley end cover in the proper relationship. Insert mounting bolts and tighten
alternately to ensure a good mechanical alignment.
9. Spin the shaft by hand to see if it is free. Be sure motor leads (if used) are not touching
together. If the leads are touching, a generator action will give the effect of friction in the
motor. A no-load test can now be performed. At rated voltage, observe the no-load current.
It should be less than 20% of the nameplate full load current. Anything higher indicates:
• Brushes are not on neutral setting (check match-marks for exact alignment).
10. Faulty armature.