BMW 7_aya the E38 series from 1994 to 2002
1. Introduction
2. Governing bodies and methods of operation
3. Settings and routine maintenance of the car
4. Engine
5. Cooling systems of the engine, heating, ventilation and air conditioning
6. A power supply system and production of the fulfilled gases
7. Systems of electric equipment of the engine
7.1. Systems of ignition, preheat and engine management
7.2. Systems of a charge and start
7.2.1. General information
7.2.2. The rechargeable battery - the general information, recommendations about service
7.2.3. System of a charge - general information and security measures
7.2.4. Removal and installation of the generator
7.2.5. Replacement of the regulator of tension
7.2.6. System of start of the engine - the general information and precautionary measures
7.2.7. Removal and installation of a starter
7.2.8. Replacement of the traction relay
8. Manual box of gear shifting and coupling
9. Automatic transmission
10. Cardan and power shafts, reducer, differential and stupichny assemblies
11. Brake system
12. Suspension bracket and steering
13. Body
14. Onboard electric equipment
15. Schemes of electric equipment


7.2.3. System of a charge - general information and security measures

On the considered cars the generator of alternating current is used. At installation of additional electric equipment check that there was enough power of the generator for providing new consumers with the electric power.

The drive of the generator is carried out by a belt from a bent shaft of the engine.

The generator represents the three-phase synchronous electrical machine with electromagnetic excitement. For transformation of alternating current in constant the diode rectifier is built in the generator. Adjustment of output tension is carried out by the built-in regulator. The generator has grounding on weight.

During the operation of the generator the electric current proceeding on an excitement winding creates a magnetic flux around rotor poles. At rotation of a rotor there is a periodic change of its magnetic poles under each tooth of the stator, as a result, the magnetic flux passing through teeth, continuously changes in size and tension. This variable magnetic flux creates the electromotive force (EMF) in a stator winding. The wedge-shaped form of polar tips of a rotor is picked up in such a way that allows to receive close to sinusoidal a form of curve EMF.

With a high frequency of rotation of a rotor when the output tension of the generator begins to exceed 13.6 ÷ 14.6 B, the regulator of tension is locked, and current does not pass through a winding of excitement. When tension decreases, the regulator opens again, providing freedom of a transmission of current through an excitement winding. The frequency of rotation of a rotor is higher, the longer the regulator remains locked and, that respectively tension at the generator exit decreases stronger. Process of locking and unlocking of the regulator happens with high frequency therefore output fluctuations remain almost imperceptible and the constants supported at the level of 14.4 Century can consider tension of the generator.

The system of charging does not demand periodic service, however check of a state and replacement of a driving belt of the generator, the rechargeable battery and its electrical wiring it is necessary to make on a regular basis according to the schedule THAT (see the Sections Check of a Condition of the Battery and Leaving behind it and Check of a condition of a belt of the drive of auxiliary units of the Head Nastroyki and routine maintenance of the car).

At inclusion of ignition on a combination of devices has to light up quickly To/L a charge (see the Head Governing bodies and methods of operation). If the lamp is not disconnected after start of the engine or lights up in the course of its functioning, check a condition of components of system of a charge. The refusal of activation of a lamp at inclusion of ignition testifies to its exit out of operation, damage of the corresponding electrical wiring, or violation of serviceability of functioning of the generator (including break of a driving belt).

Security measures at service of the generator

  • Do not switch-off the battery or the regulator of tension at the working engine;
  • Do not close the plug of excitement of the generator or the cable fixed on it on weight;
  • Do not confuse an order of connection of an electrical wiring of the regulator of tension;
  • Remember that turning on of the regulator of tension closed on weight leads to an instant exit it out of operation;
  • Never remove the generator at the connected battery;
  • Do not confuse polarity of connection of the rechargeable battery;
  • Never use the measuring instruments of tension or a lamp samplers connected to household network (110/220 B) when checking onboard electric equipment;
  • When checking a condition of diodes do not give on them voltage more than 12 V and do not use the megohm meters which also have high output voltage, - breakdown of diodes will lead to short circuit. Remember that when checking isolation of an electrical wiring by means of the megohm meter it is necessary to disconnect all electrical wiring from the generator;
  • At charging of the rechargeable battery without removal from the car track it that both wires were disconnected from it. Do not confuse polarity of connection of the charger;
  • Before carrying out on the car of any electrowelding works do not forget to disconnect an electrical wiring from the generator and the rechargeable battery;
  • You make any checks of chains and knots of an onboard electrical wiring at the idle engine and the disconnected rechargeable battery;
  • Remember that violation of polarity of any connections is accompanied by risk of irreversible failure of the rectifier and regulator of tension of the generator.

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7.2.2. The rechargeable battery - the general information, recommendations about service
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7.2.4. Removal and installation of the generator