Car alternator: what it is, device, principle of operation

The car generator is a device, the main function of which is the conversion of mechanical energy produced by the engine into electrical energy. Modern vehicles are equipped with an alternator, which is driven by the crankshaft. In the design of the car, this device has a significant role. Together with the battery, it provides electricity for lights, ignition system and electronic devices.

It is the generator that is responsible for the smooth operation of electrical appliances. In case of the slightest malfunction, their work will be blocked. Therefore, high demands are placed on the generator. A modern auto generator is not a cheap high-tech part. Let's understand the features of this unit.

Device of the generator

The car generator consists of individual elements that are assembled under one housing. The design includes such details:

• The housing consists of 2 covers: front and rear. Their purpose: fixing the stator, rotor bearings and installing the entire device on the engine. On the rear cover there is a brush assembly, voltage regulator, rectifier, external leads. Most often the housing is made of duralumin, that is, easily alloyed metals.
• The pulley transmits to the shaft of the generator mechanical energy, which it receives from the engine. This occurs by means of belt transmission.
• The rotor is a steel shaft. It has two steel sleeves, between which there is a winding. From it comes the connection to the contact rings, which are made of copper and have a cylindrical shape.
• The stator has the shape of a tube. In its grooves there is a 3-phase winding. It is in it that the power of the generator is produced.
• Voltage regulator - a device that is responsible for supporting the normal voltage of the on-board network.
• The rectifier bridge usually consists of 6 diodes.
• Brush assembly - a plastic removable structure, which contains spring-loaded brushes.

Principle of operation of an automobile alternator

The generator works when an alternating electric current flows in the stator windings. It is formed as a result of the emergence of a magnetic field around the rotor core. When the car engine is switched on, the rotor is driven into operation. A belt drive is provided for this purpose. An electrical voltage is applied to the winding, which is sufficient to produce magnetic flux. When the magnetic flux begins to pass through the coil, a voltage appears on its leads. The strength of the magnetic flux is regulated with the help of a voltage regulator. Thus, at the generator output voltage ranges from 14.2 V for the winter period and 13.6 V for the summer period. Such voltage is sufficient to maintain the battery in a charged state and its recharging.

There are two main elements in an automobile alternator. The rotor is the source of the magnetic field and consists of contact rings, shaft and pole system. The stator forms the alternating electric current. It includes a winding and a core consisting of steel plates.

Signs and main faults of the alternator

In modern cars, alternators of alternating current are used. From DC generators, they are distinguished by their lighter weight, small dimensions, simple design and low price. Like all electrical equipment, they can fail. To the signs of failure of the unit can be attributed: a change in the brightness of the lights, a weak sound signal, a dim glow of the headlights and a complete discharge of the battery.

Of the main faults of the auto generator, the most common are:

• Wear and tear of the alternator brushes. Brushes are the elements that transmit electric current from the stator to the rotor. Their wear can cause an interruption in the current and, as a result, a failure in the operation of the generator.
• Voltage regulator malfunctions. The voltage regulator controls the output voltage of the alternator. If the regulator is not functioning properly, it can cause the battery to not charge properly.
• Damage to the stator or rotor. Problems with the armature (rotor) or stator can cause the alternator to be less efficient.
• Bearing failures. Wear and tear on the bearings on which the rotor and stator rotate can lead to noise, vibration, and eventually generator failure.
• Poor connection or broken wires. Problems with the electrical connection or broken wires can cause loss of contact and result in generator failure.
• Problems with the alternator drive belt. A worn, misaligned or broken alternator drive belt can cause the alternator speed to decrease. Power generation then becomes insufficient.
• Diode Bridge Problems. The diode bridge converts the alternating current generated by the stator into direct current. Faults in the diode bridge can cause battery charging problems.

If there is a problem with the alternator, it is recommended to have the alternator checked by a specialist.