Mercedes S-class W202

1993-2000 of release

Repair and car operation

Mercedes W202
+ 1.2. The general data
+ 2. Maintenance service
+ 3. Engines
+ 4. Greasing system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. Ignition system
+ 8. Fuel system
+ 9. Transmission
+ 10. A running gear
+ 11. A steering
+ 12. Brake system
+ 13. A body
- 14. An electric equipment
   14.1.2. Measuring devices
   14.1.3. Technics of measurements
   14.1.4. Electric equipment checks
   14.1.5. A sound signal
   14.1.6. Replacements of safety locks
   + 14.1.7. The storage battery
   - 14.1.8. The generator Diagnostics of malfunctions of the generator
   + 14.1.9. A starter
   14.1.10. The traction relay
   + 14.1.11. Illumination system
   14.1.12. Devices
   14.1.13. The instrument panel
   14.1.14. Lamps накаливания on the panel of devices
   14.1.15. Light switch
   14.1.16. A radio receiver
   + 14.1.17. The aerial
   14.1.18. Dynamics
   + 14.1.19. Rubber brushes of screen wipers
   14.1.20. Jets стеклоомывателя
   14.1.21. Washing atomizers of headlights
   14.1.22. A screen wiper and its engine
   14.1.23. Protect the car
   14.1.24. Anticreeping "immunodeficiency"
   14.1.25. Why headlights grow dull
   14.1.26. "Галогенки"
+ 14.2. Electroschemes

14.1.8. The generator

Engines of cars Mercedes of the S-class work with the three-phase generator of an alternating current. Depending on model and equipment generators of various capacity are established.

The generator is put in action by means of a cranked shaft and клинового a belt. Thus the rotor rotates approximately with the doubled frequency of rotation of a shaft of the engine by means of the winding of the excitation located of inside rigidly established winding статора.

By means of coal brushes and contact rings the excitation current proceeds through an excitation winding. The electromagnetic field is thus formed. Position of an electromagnetic field constantly changes in relation to a winding статора according to rotor rotation. Thanks to it in a winding статора the three-phase current is developed. But as the storage battery can be charged only by a direct current, the three-phase current will be transformed in constant by means of the rectifier established on диодной to a payment. The pressure regulator changes зарядный a current by means of inclusion and deenergizing of a current of excitation according to degree разряженности the storage battery. Simultaneously the regulator supports to constants working pressure nearby 12 Volt irrespective of frequency of rotation.

Safety precautions at work on the alternating current generator

At work on the generator of an alternating current pay attention to points of the data below instructions. Complete dismantling and repair of the generator of an alternating current spend in a specialised repair truck.

If the additional storage battery is connected (for example, for simplification of start-up of the engine), necessarily pay attention to that identical poles of storage batteries among themselves incorporated.

At connection зарядного devices of a wire of the last connect to corresponding plugs of the storage battery. During gymnastics disconnect from plugs of the storage battery a wire from a flexible partition between a body and the engine and a positive wire.

Do not allow to work to the engine without the storage battery.

Never close накоротко plugs on the generator of an alternating current and on a regulator.

Never make переполюсовку the alternating current generator.


1. A wire of the plug 30 (In +)
2. A wire of the plug 61 (Д +)
3. Bolts
4. Contact protection
5. The generator

1. Disconnect from the plug of the storage battery a weight wire (–).
The prevention

Disconnect only at the switched off ignition, the actuation device of system of injection of fuel differently can be damaged. Before switching-off of wires from plugs of the storage battery it is necessary to read also the recommendations which are available in corresponding sections.

2. Ослабьте a tension клинового a ridge belt and only then remove it from a belt pulley of the generator.
3. Raise in front the car. If is available, remove the bottom cover of a motor compartment.
4. Remove from a generator flange contact protection (4).
5. Unscrew on the generator electric wires (1) and (2).
6. Get on the holder bolts (3) and take the generator.


1. Insert the generator, tighten fixing bolts with the moment 40 Н.м.
2. Screw a wire on the plug 30 with the moment 15 Н.м., and to the plug 61 with the moment 5 Н.м. Spread contact protection.
3. Lay and pull клиновой a belt.
4. Establish the bottom cover of a motor compartment.
5. Attach to the plug of the storage battery a weight wire (–). Establish time for hours, and also enter an anticreeping code for radio.

Check зарядного pressure of the generator

1. Connect the voltmeter between a positive and negative pole of the storage battery.
2. Start the engine. In the course of start pressure can decrease to 9,5 Century
3. At frequency of rotation of a shaft of the engine in 3000 rpm pressure should make 13,0–14,5 V.Eto proves that the generator and a regulator work.

Replacement and check of coal brushes of the generator / of a regulator of pressure

The pressure regulator is built in in the holder for coal brushes. It is possible to replace coal brushes separately, for this purpose, the truth, is necessary some skill; on the average they wear out after passage by the car about 120 000 km. We recommend to replace coal brushes slightly earlier.


1, 4. Bolts
2. A cover
3. A keeping ledge
5. A regulator
6. A ledge for connection with the car case
G2. The generator

1. Remove the generator.
2. Unscrew bolts (1), disconnect spring clips and remove a protective casing (2). Unscrew bolts (4) and take aside a regulator (5).
3. Replace coal brushes, for this purpose unsolder a multicore connecting flexible wire.
4. Check up deterioration of contact rings, if necessary grind them absolutely and polish.


1. Insert new coal brushes () and springs () in the holder of coal brushes () and solder connections.
2. That at soldering of new brushes tin solder could not rise highly in a flexible wire, support a multicore connecting flexible wire of brushes flat-nose pliers.
The prevention

Because of highly risen tin solder multicore connecting flexible wires become rigid, and coal brushes become disabled.

3. Establish a regulator of pressure and rigidly screw it. At installation pay attention to that the ledge for connection with the car case adjoined to a regulator.
4. After installation of new coal brushes check up them on ease of a course in their holders.
5. Spread a protective casing on the generator and screw it.
6. Establish the generator.