The starter, which is used to crank the engine, must overcome the combined resistance of the compression, piston friction, and bearing friction. In order to be able to provide the considerably large torque required for this purpose, the starter draws a very high current.

The design of the starter is similar to that of the generator. The main difference lies in the fact that the starter is a current consumer and the generator a current producer. The overrunning clutch coupling, mounted on the starter drive, breaks the connection between engine and starter as soon as the peripheral speed of the flywheel exceeds that of the starter pinion.