Tip 1: How the alternator works

The science

Tip 1: How the alternator works

The generator is a device that converts mechanical energy into electrical energy. The principle of operation of the alternator is based on the use of such a phenomenon as electromagnetic induction.

Instructions

In the simplest alternator, the endsThe conductor frames are attached to the rings to which the brushes of the device are pressed. The external circuit closes the brushes through a light bulb. The generator gives an alternating current when the frame with rings rotates in a magnetic field. The current changes its direction and value every half-turn, it is called single-phase.

The most convenient for use in technologythree-phase current generators are considered. The design of the simplest three-phase generator includes three wire frames, they are shifted 120 ° relative to each other along the rotation circle. Every 120 ° revolution, the current changes its magnitude and direction. Compared to a single-phase system, the three-phase system has many advantages. At the same power, it requires less metal for wiring.

An electric magnet is a rotating partdrive, its rotor, it transmits the generated magnetic field to the stator. The stator is the outer part of the device, which consists of three coils with wires.

Voltage is transmitted through rings and collectorbrushes. The rotor rings of copper rotate together with the crankshaft and rotor, as a result of which the brushes are pressed against them. The brushes remain in place, and the electric current is transferred from the fixed elements of the alternator to its rotating part.

The resulting magnetic field rotates acrossstator and produces electric streams that charge the battery. To transfer the pulse from the generator to the battery, a diode bridge is also used, it is located at the rear of the machine. The diode has two contacts, through which the current flows in one direction, the bridge usually consists of ten such parts.

Diodes are divided into two groups: basic andadditional. The former are used for rectifying the voltage, they are connected to the stator terminals. The second sends power to the voltage regulator and the charge control lamp, which is necessary to monitor the drive's operability.

Generators are divided into low-power andHigh-power, depending on the energy they produce. Low-power alternators are most often used in everyday life as backup power supplies.

Tip 2: Principle of operation of the alternator

A generator in electrical engineering is a device,by means of which the energy of a mechanical type is transformed into an electrical one. Such devices are widely used in production and in some technical systems, for example in cars. The work of the generator is based on the phenomenon of electromagnetic induction.

Alternator device

In practice, several types are usedgenerators. But each of them includes the same constituent elements. These include a magnet that creates an appropriate field, and a special wire winding, where an electromotive force (EMF) is created. In the simplest model of the generator, the role of the winding is performed by a frame capable of rotating around a horizontal or vertical axis. The amplitude of the EMF is proportional to the number of turns available on the winding and the magnitude of the magnetic flux fluctuations. To obtain a significant magnetic flux, a special system is used in the generators. It consists of a pair of steel cores. Windings that create an alternating magnetic field are placed in the grooves of the first of them. Those turns that induce EMF are placed in the grooves of the second core. The inner core is called the rotor. It rotates around the axis together with the winding on it. The core, which remains without motion, acts as a stator. To make the flux of magnetic induction the strongest, and the energy losses to be minimal, the distance between the stator and the rotor is tried to be made as small as possible.

How does the generator work?

Electromotive force occurs in stator windingsimmediately after the appearance of an electric field, for which vortex formations are characteristic. These processes are generated by a change in the magnetic flux, which is observed with accelerated rotation of the rotor. The current from the rotor is fed into the electrical circuit by means of contacts having the form of sliding elements. To make this easier, the ends of the winding are joined by rings, called contact rings. The fixed brushes are pressed against the rings through which the connection between the electric circuit and the winding of the moving rotor is made. In the coils of the magnet winding, where a magnetic field is created, the current has a comparatively small force when compared with the current that the generator gives to the external circuit. For this reason, already the designers of the first generators decided to remove the current from the windings located statically, and the weak current to the rotating magnet is fed through the contacts providing slip. In low-power generators, the field creates a permanent magnet that can rotate. Such a design makes it possible to simplify the entire system and not to use rings and brushes at all. The modern industrial electric current generator is a massive and cumbersome structure that consists of metal structures, insulators and copper veins. The dimensions of the device can be several meters. But even for such a solid structure it is very important to maintain the exact dimensions of the parts and the gaps between the moving parts of the electric machine.