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| Illustration 1 | g00719264 |
Starting motor components (1) Drive housing assembly (2) Shift lever assembly (3) Solenoid assembly (4) Brushes (5) Brush holder assembly (6) End cover assembly (7) Pinion drive assembly (8) Field winding assembly (9) Armature assembly (10) Starting motor housing | |
The major components of the starting motor are the following items:
- Starting motor housing (10)
- Field winding assembly (8)
- Armature assembly (9)
- Brushes (4)
- Brush holder assembly (5)
- Pinion drive assembly (7)
- Shift lever assembly (2)
- Solenoid assembly (3)
- Housings (1)
- End cover assembly (6)
Field Winding and Housing
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| Illustration 2 | g00718877 |
Field winding and starting motor housing (8) Field winding assembly (10) Starting motor housing | |
The starting motor housing (10) supports the field winding assembly (8), the brush holder, and the brushes. The field winding (8) provides the magnetic field for the armature assembly.
Armature Assembly
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| Illustration 3 | g00718887 |
Armature assembly (9) Armature assembly | |
The armature assembly (9) consists of a laminated iron core that is assembled on the armature shaft. The armature also has a commutator on one end. The commutator is made of copper segments (bars) insulated from each other and insulated from the armature shaft. The armature windings are wound in the slots of the core. The armature windings are also connected to the commutator segments.
The armature assembly is positioned in the field winding assembly. The armature is supported by the bushings in the drive housing assembly (1), the end cover assembly (6), and a bearing assembly in the starting motor housing.
The armature assembly and field winding assembly are connected in series. The same current flows through each component. This generates high torque, primarily when the motor is first started.
Brush Holder Assembly
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| Illustration 4 | g00718888 |
Brush holder assembly (4) Brushes (5) Brush holder assembly (11) Brush springs | |
Brush holder assembly (5) is mounted to the starting motor housing around the commutator. Brushes (4) are held against the commutator. Brush springs (11) keep pressure on the brushes so that the brushes stay in contact with the commutator. Two of the brushes (4) are positive. The positive brushes are connected to field winding assembly (8). Two of brushes (4) are negative. The negative brushes are connected to the brush holder assembly (5) .
The brushes are made of carbon. The brushes conduct electricity. The brushes transmit current from the field winding to the commutator. The brush leads are soldered to the field winding assembly and soldered to the brush holder assembly.
Pinion Drive Assembly
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| Illustration 5 | g00718889 |
Pinion drive assembly (7) Pinion drive assembly (12) Pinion gear | |
As the engine starts to run, the speed eventually exceeds the starting motor speed. The overrunning clutch portion of the pinion drive assembly (7) protects the starting motor from this overspeed condition. The mechanical connection between the engine flywheel and the starting motor is disengaged.
The pinion drive assembly (7) has a pinion gear (12) that engages the flywheel ring gear. The pinion gear will stop in case of butt engagement. As a result, the pinion drive assembly spring is compressed by the shift lever assembly until the solenoid contacts meet the solenoid terminals. The starting motor is now turned on. The starting motor turns the pinion until the pinion meshes with the ring gear. This turns the engine.
Solenoid Assembly
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| Illustration 6 | g00719269 |
Solenoid assembly (2) Shift lever assembly (3) Solenoid assembly (13) Plunger (14) Windings (15) Contact disc assembly (16) Terminals | |
The solenoid assembly (3) contains terminals (16) and the contact disc assembly (15). The disc assembly contacts the terminals when the solenoid is energized. The solenoid assembly also contains pull-in windings (14), hold-in windings (14), and a plunger (13). The energized plunger moves the contact disc assembly and the shift lever assembly to the right. The shift lever controls the pinion drive assembly.