Alternator — General Information (Mercedes-Benz Sprinter 903)

When the engine is not running, electrical consumers are powered by the battery. When the engine is running, the generator serves as the current source.

Despite its small size, the maintenance-free alternator produces a fairly high current. At idle speed, the device produces about 25 A, and at a rotation speed of 2400 min⁻¹ its maximum power is reached.

The generator brushes can withstand a mileage of more than 100,000 km. The generator is driven by a belt. Since alternating current cannot be used in a car, diodes are installed in the generator that convert alternating current into direct current. These diodes are susceptible to voltage surges. To ensure that the required power is provided even at low engine speeds, the generator rotates faster than the crankshaft. This increase in the number of revolutions is achieved due to the fact that the diameter of the generator drive pulley is smaller than the diameter of the crankshaft pulley. On the other side of the generator there is a voltage regulator.