All electrical machines operate in accordance with the law of electromagnetic induction, as well as with the law of interaction of a conductor with current and a magnetic field.
Electric machines according to the type of power supply are divided into DC and AC machines. Direct current is generated by uninterruptible power supplies. DC machines are characterized by the property of reversibility. This means that they are capable of operating in both motor and generator modes. This circumstance can be explained in terms of similar phenomena in the operation of both machines. We will consider in more detail the design features of the engine and generator below.
Engine
Engine designed for conversion of electrical energy into mechanical. In industrial production, motors are used as drives on machine tools and other mechanisms that are part of technological processes. Also, motors are used in household appliances, for example, in a washing machine.
When a conductor in the form of a closed frame is in a magnetic field, the forces that are applied to the frame will cause this conductor to rotate. In that case, it will be about the simplest engine.
As mentioned earlier, the operation of the DC motor is carried out from uninterruptible power supplies, for example, from a battery, a power supply. The motor has an excitation winding. Depending on its connection, motors are distinguished with independent and self-excitation, which, in turn, can be series, parallel and mixed.
AC motor connection is made from the electrical network. Based on the principle of operation, motors are divided into synchronous and asynchronous.
The main difference between a synchronous motor is the presence of a winding on a rotating rotor, as well as the existing brush mechanism, which serves to supply current to the windings. The rotation of the rotor is carried out synchronously with the rotation of the magnetic field of the stator. Hence the name of the engine.
In an asynchronous motor, an important condition is that the rotation of the rotor must be slower than the rotation of the magnetic field. If this requirement is not observed, the induction of the electromotive force and the occurrence of an electric current in the rotor is impossible.
Asynchronous motors are used more often, but they have one significant drawback - without changing the current frequency, it is impossible to control the speed of rotation of the shaft. This condition does not allow to achieve rotation with a constant frequency. Also a significant disadvantage is the limitation on the maximum rotation speed ( 3000 rpm.).
In cases where it is necessary to achieve a constant shaft rotation speed, the possibility of its regulation, as well as achieving a rotation speed exceeding the maximum possible for asynchronous motors, synchronous motors are used.
Generator
The conductor, moving between two magnetic poles, contributes to the emergence of an electromotive force. When the conductor is closed, then under the influence of an electromotive force, a current appears in it. This phenomenon is based on electric generator.
The generator is capable of producing electrical energy from thermal or chemical energy. However, the most widespread are generators that convert mechanical energy into electrical energy.
The main components of the DC generator:
- An anchor acting as a rotor.
- The stator on which the excitation coil is located.
- Frame.
- magnetic poles.
- Collector assembly and brushes.
DC generators are not used as often. The main areas of their application: electric transport, welding inverters, as well as wind turbines.
The alternator has a similar design to the DC generator, but differs in the structure of the collector assembly and the windings on the rotor.
As with motors, generators can be either synchronous or asynchronous. The difference between these generators lies in the structure of the rotor. A synchronous generator has inductors located on the rotor, while an asynchronous generator has special grooves for winding on the shaft.
Synchronous generators are used when it is necessary to supply current with high starting power for a short period of time, in excess of the rated one. The use of asynchronous generators is more provided for in everyday life, for the energy supply of household appliances, as well as for lighting, since electrical energy is generated with little or no distortion.
How is a generator different from an engine?
Summing up, it is important to note that the functioning of motors and generators is based on the general principle of electromagnetic induction. The design of these electrical machines is similar, but there is a difference in the configuration of the rotor.
The main difference is the functional purpose of the generator and the engine: the engine generates mechanical energy by consuming electrical energy, and the generator, on the contrary, generates electrical energy by consuming mechanical or another type of energy.
