Subject: Automobile Engineering

Topic: Electrical System, Starting Systems & Alternator

Difficulty: Medium

In over running clutch, a shift lever is provided to shift the drive gear & overrunning clutch mechanism on the armature shaft into & out of mesh with the engine flywheel. The shift lever is operated manually, by means of lever or pedal or by an electrically operated solenoid contact.
The overrunning clutch is located between the drive gear & sleeve attached to the splined armature shaft. It consists of the outer shell which contains hardened steel rollers about three or four in number, fitted into notches & the pinion and collar assembly.
The notches are not concentric but are smaller in the end opposite to the plunger spring. When the armature & shell begins to rotate, the pinion is momentarily stationary. Because of this the rollers to rotate into the smaller section of the notches where they jam light.
The drive pinion now rotate with the armature, by cranking the engine, After the engine starts it spins the pinion faster than the armature. Then the roller rotated into the larger section of the notches where they are from.
This happens due to difference in speed between the engine flywheel & armature shaft. This allows the pinion to spin independently or run the remainder of the clutch.A return spring on the shift lever pulls the drive gear back out of mesh from the flywheel, when the lever is released.