Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Generator of Bosch firm (old version), rear view

As Audi 80 cannot pull along a lengthening cable, production of electricity has to happen directly in the car. This task is carried out by the generator. And and not only for lighting as it was once, but also for all electric systems in Audi.

Three-phase generator of alternating current

Power

Approximately till December, 1991 some Audi 80 versions were equipped with the 65-ampere generator, only the 90-ampere generators are installed now. In special options there can be also 110-ampere or 120-ampere generators. To calculate generator power, it is necessary to increase the specified maximum current by rated voltage in 14 V. Poluchayetsya, for example 90 A x 14 V = 1260 W. You already noticed: the generator in a 12-voltny onboard network actually gives 14 Century. Because to the battery current for a charge only thanks to this small difference in tension can arrive.

Transfer from a pulley of a cranked shaft to a pulley of the generator is chosen, by the way, so that already on single turns about 2/3 capacities of the generator were made.

Service of the generator and safety measures

The three-phase generator of alternating current differs in rather high power and develops current even on single turns of the engine. Its sliding graphite contacts (brushes) maintain more than 80 000 km. According to the name it makes alternating current which in the car is not used as the accumulator can be charged only with a direct current. Therefore the vypryamitelny diodes turning alternating current into the pulsing direct current are built in the generator. As these diodes are sensitive to a high voltage, you should remember the following:

• At the working generator it is impossible neither to weaken, nor to connect wires between the battery and the generator. Because of it there can be a power surge (tension peaks) that will lead to damage of the diode.
• The three-phase generator of alternating current should not work in the absence of correctly connected, serviceable battery because the accumulator serves as some kind of buffer from retension.
• All cable connections between the three-phase generator of alternating current, the battery and metal of a body or the power unit ("weight", the case) have to sit tight. Can lead to dangerous peaks of tension even leaky contact.
• At a fast charge of the accumulator (not to apply at charging by means of devices to a charge with automatic shutdown) and during the electric welded works on a body both wires that diodes of the generator were not damaged have to be disconnected from the accumulator.