Audi A4

since 1994 of release

Repair and car operation

A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ exhaust System
+ cooling System
+ Fuel tank and fuel pump
+ Air filter and absorption channels
+ injection System
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
- Electrotechnical equipment
   The minus is connected to weight
   The help for orientation in the electrotechnical equipment of the car
   Connections of wires
   Central switching knot
   Support of additional relays
   Box for electronics
   Relay and control units
   Switching relay
   H-contact of the relay of unloading
   Table of the relay and control units
   Safety locks
   Table of safety locks
   + Electric circuits
   + Accumulator
   - Generator
      Generator of an alternating current
      Control bulb of a charging
      Tension regulator
      The self-help in work with the generator and a tension regulator
      Movement with the defective generator
      Maple and poliklinovy belt
      Check of a condition of a maple and poliklinovy belt
      Replacement of a maple and poliklinovy belt
      Torn maple a belt
      Review: maple and poliklinovy belt
      The help at malfunctions
   + Starter
+ ignition System
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics

Generator of an alternating current


Depending on the engine and a complete set we see in Audi A4 generators in capacity 70, 90 and 120 And. the 70-amperny generator is serially put on cars with four-cylinder engines, the 90-amperny generator enters into a serial complete set of cars with six-cylinder engines and the 120-amperny generator enters into a special complete set.

To define generator capacity, it is necessary to multiply the specified maximum current by rated voltage in 14 V.Naprimer, 90А X 14 In = 1260 W.

You already noticed: the generator really delivers 14 In at 12 In in an onboard network. I.e. only at such small distinction in tension the current can flow to the accumulator in order that it to charge.

Transfer from a belt pulley of the crankshaft to a belt pulley of the generator is so chosen that on single turns about 2/3 capacities of the generator can already be made.

Handling of the generator and precautionary measures

The generator of an alternating current along with the quite high capacity possesses decided advantage: it submits a current already on single turns of the engine. Besides, its graphite brushes maintain the run considerably exceeding 80 000 km. As it is clear according to the name, it makes an alternating current which we cannot use in the car as the accumulator can keep only a direct current, of course. Therefore in the generator three diode rectifiers which will transform an alternating current to a pulsing direct current are built in. These diodes are sensitive to high tension and consequently you should consider the next moments:


    At the working engine it is impossible neither to remove, nor to connect any wire between the accumulator and the generator. At the expense of it tension (tension peaks) can sharply increase and to "overheat" the diode. The generator of an alternating current should not work without correctly connected and serviceable accumulator. The accumulator serves for the generator somewhat as the buffer at tension peaks. All connections of wires between the generator of an alternating current, the accumulator and metal of a body or the engine block (weight) should be strong. Even shaking contact can lead to power surges. At the accelerated battery charging (it is impossible to use for a charging in house conditions) and at welding works on a body should be disconnected from the accumulator both of a wire not to damage generator diodes.

In models with four-cylinder engines the generator (2) settles down at the left ahead near the engine and is available from above. Figure «1» showed the top fixing bolt.

Type of the six-cylinder engine from below. The generator (2) takes place on the right below about the engine. For cooling of the generator the air channel (1) (here it is dismantled for the sake of presentation of the image) is connected.