When the engine is not running, electricity consumers are powered by the battery. When the engine is running, the alternator serves as the power source.
Despite its small size, the maintenance-free alternator generates quite a lot of current. At idle engine speed, the device produces about 25 A, at a speed of 2400 min-1, its maximum power is reached.
The alternator 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 to direct current. These diodes are susceptible to voltage surges. In order to provide the necessary power even at low engine speeds, the generator rotates faster than the crankshaft. This increase in speed is achieved due to the fact that the diameter of the alternator drive pulley is smaller than the diameter of the crankshaft pulley. On the other side of the generator is a voltage regulator.