Upright TM12, Руководство по обслуживанию и запасным частям

Страница: 56 / 102

Page 3-30
Maintenance
3.17 - Electric Motor
TM12 Work Platform - European
3.17 E
LECTRIC
M
OTOR
T
ROUBLESHOOTING
1. Read the nameplate to become familiar with the motor, especially the rated voltage.
2. Try to turn the shaft by hand. Keep motor leads separated while doing this. If the shaft turns
freely go to step 3. If the shaft won't turn, proceed to step a.
a. The shaft could be tight for a number of reasons, this check is to determine if
the tightness is of a temporary nature only. Obtain power to produce the name-
plate voltage. Do not Make A Permanent Connection. First touch the motor
leads quickly to the power supply just long enough to observe if the shaft runs.
If it does turn, then hold the motor leads on the power supply for a longer time.
If the motor sounds normal, go to Step 3. If the motor sounds noisy, it should
be taken apart as described in the disassembly section.
3. If the motor turned freely, connect an ammeter in the circuit as shown in Figure 3-28A. With
rated voltage applied and the shaft running free, the ammeter should read less than 20% of
the nameplate full load current. If the motor meets the above conditions, then it can be
assumed the original problem is external to the motor.
D
ISASSEMBLY
1. Remove throw bolts.
2. Remove pulley end cover.
3. Pull the armature out of the assembly in one swift motion.
4. Remove commutator end cover.
NOTE: Do not place the stator ring in any mechanical holding device during the disassembly or assembly
operation. Permanent distortion or other damage will result.
I
NSPECTION
Once the motor has been disassembled, go through the following check-list steps to determine
where the problem lies.
1. Bearings should spin smoothly and easily and have ample lubrication and be free of corro-
sion.
2. Armature should be checked for grounds and shorted turns. Re-finish commutator surface if
pitted or excessively worn.
3. Brushes should be checked for wear and to ensure that they are free in the brush holders.
NOTE: Observe how brushes are assembled in brush holders and position of brush lead. New brushes
must be installed in the same manner. Brushes should be removed as follows:
• Remove brush spring clip from its mounting on brush assembly.
• Lift brush assembly from brush holder.
• Disconnect brush assembly lead.
• New brush assembly to be installed by reversing above procedure.
4. Inspect wire harness and all connections for signs of damage due to overheating.
5. Check stator to see if it is securely mounted.