7.2. Power supply system
The system of power supply consists of the generator, a regulator of tension and the storage battery. At collaboration of these devices a food of such consumers of the electric power, as ignition, headlights, a radio receiver is provided, etc.
On cars generators of an alternating current are established. At installation of additional electric equipment check, that capacities of the generator was enough for a food of this equipment. Basic elements of the generator – a rotor, a stator, the rectifier, collector brushes, an electronic regulator of tension, bearings and a belt pulley.
The drive of the generator is carried out by a belt from a cranked shaft of the engine.
The generator represents the three-phase synchronous electric car with electromagnetic excitement. For transformation of an alternating current in constant the rectifier is built in the generator on diodes. Tension is regulated by the built-in electronic regulator of tension.
At operation of the generator the electric current proceeding on a winding of excitement, creates a magnetic stream round rotor poles. At rotor rotation under each tooth of a stator there is that southern, the North Pole of a rotor; the working magnetic stream passing through teeth of a stator, changes on size and tension. This variable magnetic stream creates an electromotive power in a stator winding. The Klinovy form of polar tips of a rotor is picked up in such a manner that allows to receive the form of a curve electromotive power close to the sinusoidal.
At high frequency of rotation of a rotor of the generator when tension of the last becomes more than 13,6-14,6 In, the regulator of tension is locked, and the current does not pass through a winding of excitement. Tension of the generator falls, – the regulator opens and again passes a current through an excitement winding. The frequency of rotation of a rotor of the generator is higher, the it is more time of the locked condition of a regulator, therefore, the more strongly tension on a generator exit decreases. Process of locking and unlocking of a regulator occurs to high frequency therefore tension fluctuations on an exit of the generator are not appreciable and it is almost possible to consider it to the constants supported at level of 13,6-14,6 Century.
At checks of the generator and operation of the car it is necessary to observe a number of rules not to put the generator out of action:
– not to allow operation of the generator with the storage battery disconnected from its clip. Without the storage battery in an onboard network of the car there are dangerous impulses of an overstrain at shutdown of any consumers of the electric power. They can put out of action the electronic equipment of the car, including a regulator of tension and diodes of the vypryamitelny block of the generator;
– not to check operability of the generator «on a spark» even short-term connection of a "plusovy" clip of the generator with in "weight" as in this case via diodes the considerable current proceeds, and they are damaged. To supervise tension of the generator it is possible only the voltmeter;
– the negative plug of the storage battery should incorporate always to "mass" of the car, and positive – with a generator clip. Erroneous (return) turning on of the battery will immediately cause passing of the raised current via generator diodes, and they will fail;
– not to check diodes tension more than 12 In or megommetry as it has too high tension for diodes, and at check they will be punched (there will be a short circuit). At check of isolation of electroconducting megommetry it is necessary to disconnect all wires from the generator;
– it is necessary to disconnect all wires from the generator and the storage battery at electric welding of any details of a body;
|Fig. 7.1. System of power supply of the Mazda 3 car: 1–generator of an alternating current; 2–starter
– to check chains and knots of electric equipment and to eliminate malfunctions it is necessary at the idle engine and the disconnected storage battery.