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| Illustration 1 | g00719273 |
Rest position (1) Return spring (2) Solenoid assembly (3) Pull-in winding (4) Start terminal "S" (5) Hold-in winding (6) Battery terminal "Bat" (7) Key start switch (8) Solenoid contacts (9) Motor terminal "Mtr" (10) Shift lever assembly (11) Field winding assembly (12) Pinion drive assembly (13) Pinion (14) Armature assembly (15) Battery | |
A DC series wound motor is used as the starting motor. The starting motor has a field winding assembly (11). The starting motor has an armature assembly (14). The excitation windings and the armature windings are connected in series. The pinion end of the armature shaft has splines for the pinion drive assembly (12) .
The solenoid assembly (2) is an integral part of the starting. The assembly has a pull-in winding (3) and a hold-in winding (5). The shift lever assembly (10) fits in the solenoid plunger slot. There is a small amount of free play between the shift lever assembly (10) and the solenoid plunger. This free play allows return spring (1) to pull the solenoid plunger back to the initial position. The movement turns the starter off. The electrical connection is quickly broken at the solenoid contacts (8). The connection is quickly broken in order to turn off the starting motor if the engine is not started.
The pinion drive assembly (12) contains a pinion (13) and an overrunning clutch. The pinion drive assembly (12) engages the helical spline of the armature shaft. The pinion drive assembly is coupled to pinion (13) with an overrunning clutch. The drive has two guide rings or discs which are engaged with the forked end of shift lever assembly (10). The shift lever assembly (10) moves the drive along the armature shaft. A meshing spring separates the guide ring from the overrunning clutch portion of pinion drive assembly (12). The spring allows the shift lever assembly to move against the stop. As a result, the starting motor current is always turned on. The current is on even if the flywheel is not engaged by the pinion. The pinion drive assembly and pinion (13) are moved by the shift lever assembly axially until the pinion reaches the stop position. The helical spline prevents torque from being applied to the engine until the pinion is fully meshed. The overrunning clutch portion of pinion drive assembly (12) transmits the force of the starting motor armature to the engine flywheel after pinion (13) is fully meshed. The pinion drive assembly (12) breaks the connection immediately after the engine speed exceeds the speed of the starting motor.
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| Illustration 2 | g00719279 |
Partial engagement (1) Return spring (2) Solenoid assembly (3) Pull-in winding (4) Start terminal "S" (5) Hold-in winding (6) Battery terminal "Bat" (7) Ignition switch (8) Solenoid contacts (9) Motor terminal "Mtr" (10) Shift lever assembly (11) Field winding assembly (12) Pinion drive assembly (13) Pinion (14) Armature assembly (15) Battery | |
Upon closing the switch (7), the pull-in winding (3) is energized and the hold-in winding (5) is energized. The solenoid armature pulls the shift lever assembly (10) against the force of the return spring (1). The shift lever assembly pushes the pinion drive assembly (12) toward the engine flywheel. The armature assembly (14) has not yet turned because the solenoid contacts (8) have not closed. Closing of the solenoid contacts sends starting motor current to the excitation windings and to the armature windings. If the pinion (13) can immediately engage the flywheel ring gear, the pinion moves forward. The pinion moves forward until the pinion reaches the end of travel. At that point, the pinion reaches the end of the travel. The solenoid contacts (8) close. At this point, the starting motor is in partial engagement.
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| Illustration 3 | g00719280 |
Blocked engagement (1) Return spring (2) Solenoid assembly (3) Pull-in winding (4) Start terminal "S" (5) Hold-in winding (6) Battery terminal "Bat" (7) Ignition switch (8) Solenoid contacts (9) Motor terminal "Mtr" (10) Shift lever assembly (11) Field winding assembly (12) Pinion drive assembly (13) Pinion (14) Armature assembly (15) Battery | |
If a pinion tooth meets a ring gear tooth, the pinion cannot immediately mesh with the ring gear. The meshing spring is compressed through the shift lever assembly (10) until the contacts of the solenoid (8) close. The starting motor is now turned. The movement turns the pinion (13) until the pinion can mesh with the teeth of the ring gear. The pressure that is exerted by the meshing spring causes the pinion (13) to mesh with the ring gear.
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| Illustration 4 | g00719282 |
Full engagement (1) Return spring (2) Solenoid assembly (3) Pull-in winding (4) Start terminal "S" (5) Hold-in winding (6) Battery terminal "Bat" (7) Ignition switch (8) Solenoid contacts (9) Motor terminal "Mtr" (10) Shift lever assembly (11) Field winding assembly (12) Pinion drive assembly (13) Pinion (14) Armature assembly (15) Battery | |
At the end of solenoid armature travel, the solenoid contacts (8) close regardless of the pinion position. This allows full battery voltage to be applied to battery terminal "Bat" (6) and to the motor terminal "Mtr" (9). Starting motor current flows in order to energize the field winding (11). Starting motor current flows in order to power the starting motor. The armature (14) now begins to rotate. The helical spline forces the pinion farther into the ring gear until the pinion contacts the stop ring of the armature shaft.
When the starting circuit is closed, the pull-in winding (3) is turned off. Hold-in winding (5) remains energized. The hold-in winding magnetic force is enough to hold the solenoid plunger in the solenoid plunger pulled in position until the engine is started.
When the engine starts and the ring gear turns the pinion (13) faster than the starting motor, the clutch section of pinion drive assembly (12) breaks the connection between the pinion and the armature shaft. This prevents damage to the armature from being rotated too fast. While the pinion is meshed with the ring gear, the shift lever assembly (10) is held in the engaged position. The shift lever assembly and the pinion drive assembly are returned to the rest position. The pinion drive assembly is returned to the rest position by return spring (1) only when the starting motor is turned off. The return spring keeps the pinion in the rest position until the starting motor is operated again.