DRESSTA TD-25M EXTRA, Руководство по обслуживанию, Страница: 321 / 595

ELECTRICAL
SECTION 8
Page 45
DRESSTA TD-25M EXTRA
CRANKING MOTOR 42 MT
4. Failure to operate with no current draw indicates:
a. Open field circuit. This can be checked after disassembly by inspecting internal connections
and tracing circuit with a test lamp.
b. Open armature coils. Inspect the commutator for badly burned bars after disassembly.
c. Broken brush springs, worn brushes, high insulation between the commutator bars or other
causes which would prevent good contact between the brushes and commutator.
5. Low no-load speed and low current draw indicate:
a. High internal resistance due to poor connections, defective leads, dirty commutator and
causes listed above under Number 4.
6. High free speed and high current draw indicate shorted fields.
If shorted fields are suspected, replace the field coil assembly and check for improved
performance.
g. Disassembly
Normally the cranking motor should be disassembled only so far as is necessary to make repair
or replacement of the defective parts. As a precaution, it is suggested that safety glasses be worn
when disassembling or assembling the cranking motor.
1. Note the relative position of the solenoid, lever housing, and nose housing so the motor can
be reassembled in the same manner.
2. Disconnect field coil connector from solenoid motor terminal, and ground return lead from
solenoid if present.
3. On motors which have brush inspection plates, remove the plates and then remove the brush
lead screws. This will disconnect the field leads from the brush holders.
4. Remove the attaching bolts and separate the commutator end frame from the field frame.
5. Separate the nose housing and field frame from lever housing by removing attaching bolts.
6. Remove armature and clutch assembly from lever housing.
7. Separate solenoid from lever housing by pulling apart.
h. Cleaning
The drive, armature and fields should not be cleaned in any degreasing tank, or with grease
dissolving solvents, since these would dissolve the lubricant in the drive and damage the insulation
in the armature and field coils. All parts except the drive should be cleaned with mineral spirits and
a brush. The drive can be wiped with a clean cloth.
If the commutator is dirty may be cleaned with No. 00 sandpaper. NEVER USE EMERY CLOTH
TO CLEAN COMMUTATOR.
i. Brushes and Holders Servicing
Inspect the brushes for wear. If they are worn excessively when compared with a new brush, they
should be replaced. Make sure the brush holders are clean and the brushes are not binding in the
holders. The full brush surface should ride on the commutator to give proper performance. Check
by hand to insure that the brush springs are giving firm contact between the brushes and
commutator. If the springs are distorted or discolored, they should be replaced.