The electric motor converts electricity into mechanical energy. It consists of a stator (or armature) and a rotor. Such a device has become very widespread in all spheres of life. Thanks to electric motors, it was possible to replace human labor with machine work in many areas. Let's look at different types of motors and find out where electric motors are used (see examples below).
Working principle
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 AC motors of synchronous and asynchronous types 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.
Rotors can be short-circuited (like a squirrel cage) and phase with a winding(system of contact rings). Cases where the latter type of motor is used are asynchronous type devices for current reduction and speed control.
The movable part in a DC device or working according to this principle in a universal motor is called an armature. A universal motor is a DC motor that has series excitation, that is, the armature and winding are connected in series. There is no direct current reactance. Therefore, if you remove the electrical unit from the grinder, then it will continue to work, especially if the mains voltage is low and the current used is constant.
AC Motors
Considered devices are AC and DC. In all areas where an electric motor is used, it often has an alternating current. This motor has a simple principle of operation and is easy to operate. The only significant disadvantage is the unregulated speed.
AC motors can be single phase or multiple phase. Appliances using an AC motor are machines that do not need to adjust the speed. They can have different 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 andmixed connection of stator and armature windings. Their advantage is that the previous type is not available: it is the ability to regulate the speed of rotation. However, the operation requires the use of force.
Such motors are brushless and collector.
Brushless or valve motors are motors operating in a closed system with a sensor that determines the rotary position and control system.
Collector motors can be self-excited (parallel, series 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 type electric motors is common in many branches of technology, in household appliances (refrigerators, washing machines, air conditioners), in industry, such as wood and metalworking, as well as in weaving. They are more stable than other types, cost less and are easy to operate.
Synchronous View
The synchronous motor has excellent rotaryconstruction, 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 kind of electric motor can be used in pumping stations, when reactive power compensation is needed, and also in some other cases.
Types of torque occurrence
According to how the torque appears, electric motors are divided into hysteresis and magnetoelectric.
The most common in traditional industries is the use of electric motors of the magnetoelectric type. They can be both direct and alternating current. There are also universal motors.
But the industries where hysteresis electric motors are used cannot be called common. Typically, such devices are non-traditional and are rarely used in industry. More of them are used in gyroscopy, time counters, as well as in devices for recording sounds and images.
Universal brushed motors
Where are universal collector type electric motors used? Without them, industrial and household appliances do not function, for example, fans, juicers, meat grinders, vacuum cleaners, refrigerators, and the like. They operate on both 110 and 220 volt DC and 127 and 220 volt AC.
The device of such motors is similar to bipolar DC motors, which hassequential excitation.
Here, not only an anchor from sheet-type electrical steel is typed, but also a pole and a yoke, that is, a fixed part of the magnetic wire.
The excitation winding can be connected on one or the other side of the armature. This reduces the radio interference generated by the motor. The same speed for both direct and alternating current is achieved by implementing an excitation winding with taps. The only difference is that with a direct current network it is fully used, and with an alternating current it is only partially used.
Torque is obtained through the interaction of the current with the excitation magnetic flux.
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 speeds of two thousand seven hundred and seventy to eight thousand revolutions per minute. Since the starting currents are small here, starting resistances are not needed. The minimum number of pins on universal collectors is four. Of these, two serve to connect to the DC network, and the other two - for AC. Moreover, in the latter case, the efficiency of the engine will be lower due to large electrical and magnetic losses. Alternating current will be consumed more than direct current, since it has not only an active component, but also a reactive one.
The speed can be controlled, for example, by an automatic transformer orrheostat.
Quickly find the right gear
It is clear that there are many applications where the electric motor is used.
195 3730.12.40 is an example number for identifying a particular mechanism, as well as its dimensions.
Due to the fact that there are a huge number of models of these devices, and of various sizes and areas of use, it can be extremely difficult to find what you need. This classification greatly simplifies the process of finding a suitable electric motor.
