An electric motor converts electricity into mechanical energy. It consists of a stator (or anchor) and a rotor. Such a device has become very widespread in all areas of life. Thanks to electric motors, it was possible to replace human labor in many areas with machine work. Consider the different types of motors and find out where the motors are used (see examples below).
Principle of operation
The electric motor is quite simple. It is based on the principle of electromagnetic induction. The installation includes a fixed part - a stator mounted in synchronous and asynchronous type alternating current motors or an inductor (for a DC motor), as well as a rotor, that is, a moving part for synchronous and asynchronous types, or an armature for DC devices.
The rotors can be squirrel-cage (like a squirrel cage) and phase with a winding (slip ring system). In cases where the latter type of motor is used, asynchronous type devices are used to reduce current and control the speed.
The movable part in a DC device or working on this principle in a universal motor is called an anchor. A universal motor is a direct current motor having sequential excitation, that is, the series connection of the armature and winding. There is no DC reactance . Therefore, if you remove the electrical unit from the grinder, it will continue to work, especially if the mains voltage is low and the current used is constant.
AC Motors
The devices in question are AC and DC. In all areas where an electric motor is used, more often it has an alternating current. Such a motor has a simple principle of operation and is easy to operate. The only significant minus is the unregulated speed.
AC electric motors can be with one or several phases. Devices where an AC motor is used are those machines that do not need to adjust the speed. They can have various purposes (crushers, pumps, woodworking machines and so on). Their power ranges from two tenths to two hundred and more kilowatts.
DC Motors
DC electric motors can have, along with serial, parallel and mixed connection of the stator windings and the armature. Their advantage is that it is not available to the previous form: it is the ability to control the speed. However, the use of force is necessary during operation.
Such motors are brushless and collector.
Brushless, or valveless, are motors that operate in a closed system with a sensor that determines the rotor position and control system.
Collector motors can be self-excited (parallel, sequential and mixed) and independent excitation.
Devices where DC motors are used are, for example, electric vehicles and various construction machines.
Asynchronous view
The most commonly used three-phase squirrel-cage induction motor. In this case, a circular magnetic field penetrates the short-circuited rotor winding, which causes an induction current. It is called asynchronous because the rotation of the rotor is not equal to the rotation of the magnetic stator.
The use of asynchronous electric motors is common in many branches of technology, in household appliances (refrigerators, washing machines, air conditioners), in industry, for example, in wood and metal, as well as in weaving. They work more stable than other types, are cheaper and easy to operate.
Synchronous view
The synchronous motor has an excellent rotor design, where this part is represented by an electric or permanent magnet. The rotation frequency in this case of the magnetic stator coincides with the rotor frequency.
This type of electric motors can be used in pumping stations, if necessary, reactive power compensation, as well as in some other cases.
Types of Torque
According to how torque appears, electric motors are divided into hysteretic and magnetoelectric.
The most common in traditional industries is the use of magnetoelectric motors. They can be both direct and alternating current. There are also universal engines.
But the industry, where hysteresis motors are used, can not be called common. Typically, such devices are unconventional and are rarely used in industry. Most of them are used in gyroscopy, time meters, as well as in devices for recording sounds and images.
Universal collector motors
Where are universal collector type electric motors used? Without them, industrial and household appliances, for example, fans, juicers, meat grinders, vacuum cleaners, refrigerators and the like, do not function. They operate both from one hundred and ten and two hundred and twenty volts direct current networks, and from 127 and 220 volts from alternating current networks.
The arrangement of such motors is similar to bipolar DC motors having series excitation.
Here, not only the anchor from the sheet-type electrical steel is dialed, but also the pole and the yoke, that is, the fixed part of the magnetic wire.
The field winding can be connected from either one or the other side of the armature. Due to this, the radio interference generated by the motor is reduced. The same speed at both direct and alternating current is achieved through the implementation of the field winding with branches. The only difference is that with a DC network, it is fully used, and from AC - only partially.
The torque is obtained through the interaction of the current with the magnetic flux of the excitation.
Such motors have a power of only five to six hundred watts (but in some cases, for example, in electric tools, they reach eight hundred watts), as well as rotational speeds from two thousand seven hundred seventy to eight thousand revolutions per minute. Since inrush currents are small here, inrush resistances are not needed. The minimum number of conclusions on universal collectors is four. Of these, two are for connecting to a DC network, and the other two are for alternating current. Moreover, in the latter case, the engine efficiency will be lower due to large electrical and magnetic losses. Alternating current will be consumed more than direct, since it has not only an active component, but also a reactive one.
The speed can be regulated, for example, by an automatic transformer or rheostat.
Quickly find the right gear
It is clear that there are many areas where an electric motor is used.
195 3730.12.40 - this is an example number for identifying a particular mechanism, as well as its dimensions.
Due to the fact that there are a lot of models of these devices, moreover, of various sizes and areas of use, it is extremely difficult to find the necessary. This classification greatly simplifies the process of finding a suitable electric motor.