A generator in electrical engineering is a device by which energy of a mechanical type is converted into electrical energy. Such devices are widely used in manufacturing and in some technical systems, for example, in cars. The operation of the generator is based on the phenomenon of electromagnetic induction.
Alternator device
In practice, several types of generators are used. But each of them includes the same building blocks. These include a magnet, which creates the appropriate field, and a special wire winding, where an electromotive force (EMF) is generated. In the simplest model of the generator, the role of the winding is played by a frame that can rotate around a horizontal or vertical axis. The EMF amplitude is proportional to the number of turns on the winding and the amplitude of the magnetic flux oscillations.
To obtain a significant magnetic flux, a special system is used in generators. It consists of a pair of steel cores. The windings, which create an alternating magnetic field, are placed in the slots of the first of them. Those turns that induce EMF are laid in the grooves of the second core.
The inner core is called a rotor. It rotates around the axis along with the winding on it. The core that remains motionless 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.
What is the principle of the generator
The electromotive force arises in the stator windings immediately after the appearance of an electric field, which is characterized by vortex formations. These processes are generated by a change in magnetic flux, which is observed during accelerated rotation of the rotor.
The current from the rotor is supplied to the electrical circuit using contacts in the form of sliding elements. To make this easier, rings called contact rings are attached to the ends of the winding. Fixed brushes are pressed against the rings, through which the connection between the electrical circuit and the winding of the moving rotor is carried out.
In the turns of the magnet winding, where a magnetic field is created, the current has a relatively small strength when compared with the current that the generator gives to the external circuit. For this reason, the designers of the first generators decided to divert the current from the statically arranged windings, and to supply a weak current to the rotating magnet through the contacts providing sliding. In low power generators, the field creates a permanent magnet that can rotate. This design allows you to simplify the entire system and do not use rings and brushes at all.
A modern industrial generator of electric current is a massive and bulky structure, which consists of metal structures, insulators and copper conductors. The device can be several meters in size. 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.
