We live in a real ocean of energy, it surrounds us everywhere. Even a fixed stone lying on the road can potentially do the job. Sometimes it’s hard to believe, but the energy is one. It is only being transformed, changing its nature. This property is used by man-made electric machines.
If electric energy is supplied to the input, and at the output it is transformed into mechanical work in the form of shaft rotation, then we can say with confidence that we are talking about the engine. In turn, the conversion of mechanical work into electricity is assigned to the generator. An important feature is the fact that the same electric machines are characterized by the possibility of functioning as a consumer (engines) and a producer (generator) of electricity. This is due to the same device. However, due to the design features, operation in the non-native mode is characterized by lower efficiency.
Electric DC machines are divided into two classes: inductor and collector. The second most prevalent (a sign of the presence of a brush mechanism). The principle of operation is as follows: on a fixed part of the machine (stator) a permanent magnet is placed , creating lines of field strength.
The winding of the anchor can be represented as consisting of many frames of copper wire connected in such a way that the beginning and end are displayed on opposite lamellas of the collector. From outside, a constant voltage is applied to these conclusions by means of graphite brushes. And since there is a closed circuit, an electric current arises. Moving charge carriers generate around themselves their own field of a magnetic nature, which begins to interact with the stator field. As a result, a force arises that causes the anchor to rotate. Only the main points are described, but they are enough to understand how DC electric machines work. Of particular note is only the universal collector motor, possessing the design inherent in DC machines, it is able to operate from a 220 V household network. This is possible due to the sequential method of connecting the armature and field windings. In household hand-held power tools, they are used.
Electric AC machines are structurally simpler and more reliable, and their production costs are lower. They are divided into synchronous, in which the mechanical speed with which the rotor is drawn coincides with the frequency of rotation of the stator field, as well as asynchronous varieties, in which the rotor lags behind the field (slips). The former are more rational to use at capacities of more than 100 kW.
The simplest AC electric machines are represented by three-phase asynchronous squirrel-cage rotor (protein cell). Three windings shifted one relative to the other by 120 ° are placed on the stator. It is to them that the alternating current of the corresponding phases is supplied. The rotor has its own winding, short-circuited, thereby forming a circuit for the passage of the induced current. It is worth applying voltage to the stator pole poles, as a magnetic field is generated around them - this is one of the basic properties of directional electron movement. And since the current is alternating, then the field turns out to be rotating. Its tension lines cross the turns of the rotor winding and create an induced current (the law of electromagnetic induction is applicable). And since the movement of particles with a charge arose, then around them, in turn, a magnetic field also appears. It also rotates (the direction can be found using the rule of the gimlet). As a result, two magnetic fields are present inside the machine body. Then everything is simple: thanks to Ampere’s law , a force arises that tends to displace the windings, and since the rotor shaft is mounted on bearings, the force creates a moment of rotation. To complete the work, it remains only to connect the actuator to the shaft.