General Information
 | |
| Illustration 1 | g00584068 |
Rest Position (1) Armature reduction gear (2) Armature (3) Field winding (4) Brushes (5) Idler reduction gear (6) Overrunning clutch gear (7) Pinion (8) Overrunning clutch (9) Solenoid contacts (10) Plunger (11) Return spring (12) Hold-in winding (13) Solenoid (14) Pull-in winding (15) Key start switch (16) Battery | |
A DC Series wound motor is used as the starting motor. The starting motor has a field winding (3) and armature (2). The excitation and armature windings are connected in series. The armature drives overrunning clutch (8) through gears (1), (5) and (6). The end of the solenoid (13) has splines for the overrunning clutch (8). The solenoid is an integral part of the starting motor. The solenoid pushes the overrunning clutch (8) with pinion (7) toward the flywheel ring gear. The end of plunger (10) is a spool which is connected to the overrunning clutch through splines. Return spring (11) helps return the overrunning clutch to the rest position after the key start switch (15) is released and solenoid contacts (9) are opened. Overrunning clutch (8) protects armature (2) from an overspeed condition. The clutch also allows a smooth engagement of pinion (7) into the flywheel ring gear. The overrunning clutch is held on the splines of the solenoid. The reduction gears will reduce the speed of the pinion. The speed of pinion (7) is reduced by 25 percent to 33 percent of the armature.
Operation
 | |
| Illustration 2 | g00584084 |
(1) Armature reduction gear (2) Armature (3) Field winding (4) Brushes (5) Idler reduction gear (6) Overrunning clutch gear. (7) Pinion (8) Overrunning clutch (9) Solenoid contacts (10) Plunger (11) Return spring (12) Hold-in winding (13) Solenoid (14) Pull-in winding (15) Key start switch (16) Battery | |
When switch (15) is closed, battery current will flow in two directions. Current flows from battery (16) to switch (15). The current from the battery flows through the pull-in winding (14), field winding (3), armature (2), brushes (4), and ground. Current also flows through hold-in winding (12) to ground. The activation of pull-in winding (14) and hold-in winding (12) produces a magnetic force. The force that is produced pulls plunger (10) to the left. This moves clutch (8) and pinion (7) toward the flywheel ring gear.
 | |
| Illustration 3 | g00584092 |
The Solenoid Contacts Closed. (1) Armature reduction gear (2) Armature (3) Field winding (4) Brushes (5) Idler reduction gear (6) Overrunning clutch gear (7) Pinion (8) Overrunning clutch (9) Solenoid contacts (10) Plunger (11) Return spring (12) Hold-in winding (13) Solenoid (14) Pull-in winding (15) Key start switch (16) Battery | |
When plunger (10) is pulled to the left, solenoid contacts (9) close. At this point, pinion (7) is close to meshing with the flywheel ring gear. When this happens, pull-in winding (14) is shorted. This causes the current to flow through the solenoid contacts (9), field winding (3), armature (2), brushes (4), and ground. Current still flows through hold-in winding (12) to ground. When the starting motor is activated the pinion engages the flywheel ring gear and the engine begins to crank. At this time, the plunger is kept in the pull-in position only by the magnetic force of the hold-in winding.
 | |
| Illustration 4 | g00584170 |
The Key Start Switch Released. (1) Armature reduction gear (2) Armature (3) Field winding (4) Brushes (5) Idler reduction gear (6) Overrunning clutch gear (7) Pinion (8) Overrunning clutch (9) Solenoid contacts (10) Plunger (11) Return spring (12) Hold-in winding (13) Solenoid (14) Pull-in winding (15) Key start switch (16) Battery | |
As soon as the engine starts, the flywheel ring gear turns pinion (7) faster than the starting motor. Overrunning clutch (6) breaks the mechanical connection between the clutch and the starting motor. When switch (15) is released, current now flows through both hold-in winding (12) and pull-in winding (14) in the same direction. This causes the hold-in winding magnetic force to be reduced. Solenoid contacts (9) are opened. Plunger (10) and overrunning clutch (8) are pulled back to the original position by the force of return spring (11). The rotating armature stops. The motor is now turned OFF.