The motor is an important part of the transmission and control system. With the development of modern science and technology, the focus of the motor in practical applications has begun to shift from the simple transmission to the complicated control; especially the speed, position and rotation of the motor. Precise control of the moment. However, the motor has different design and driving methods depending on the application. At first glance, it seems that the selection is very complicated, so in order to make a basic classification according to the use of the rotating electric machine. Below we will gradually introduce the most representative, most commonly used and most basic motors in the motor – control motor and power motor and signal motor. One: control motor
The control motor is mainly used in precise speed and position control, and is used as an “actuator” in the control system. Can be divided into servo motor, stepper motor, torque motor, switched reluctance motor, DC brushless motor and so on.
Servo motors are widely used in various control systems to convert the input voltage signal into mechanical output on the motor shaft and drag the controlled components to achieve control purposes. Generally, the servo motor requires the speed of the motor to be controlled by the applied voltage signal; the speed can be continuously changed as the applied voltage signal changes; the torque can be controlled by the current output by the controller; the motor is reflected quickly, The volume should be small and the control power should be small. Servo motors are mainly used in various motion control systems, especially in servo systems.
The servo motor has DC and AC. The earliest servo motor is a general DC motor. When the control accuracy is not high, the general DC motor is used as the servo motor. With the rapid development of permanent magnet synchronous motor technology, most servo motors refer to AC permanent magnet synchronous servo motors or DC brushless motors.
2. Stepper motor
The so-called stepper motor is an actuator that converts electrical pulses into angular displacement; more generally, when the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle in the set direction. We can control the angular displacement of the motor by controlling the number of pulses to achieve precise positioning. At the same time, the speed and acceleration of the motor can be controlled by controlling the pulse frequency to achieve the purpose of speed regulation. At present, the more commonly used stepping motors include reactive stepping motors (VR), permanent magnet stepping motors (PM), hybrid stepping motors (HB), and single-phase stepping motors.
The difference between a stepper motor and a normal motor is mainly in the form of its pulse drive. It is this feature that the stepper motor can be combined with modern digital control technology. However, the stepping motor is not as good as the traditional closed-loop controlled DC servo motor in terms of control accuracy, speed variation range and low-speed performance; therefore, it is mainly used in applications where the accuracy requirements are not particularly high. Stepper motors are widely used in various fields of production practice because of their simple structure, high reliability and low cost. Especially in the field of CNC machine tools, because stepper motors do not require A/D conversion, The digital pulse signal is directly converted into an angular displacement, so it has been considered as the most ideal CNC machine tool actuator.
In addition to its application on CNC machines, stepper motors can also be used on other machines, such as motors in automatic feeders, as general-purpose floppy disk drives, as well as in printers and plotters.
In addition, stepper motors also have many drawbacks; stepper motors can run normally at low speeds due to the no-load start-up frequency of stepper motors, but they cannot start at higher speeds than with a certain speed, accompanied by sharp howling sounds; The accuracy of the subdivision driver of the manufacturer may vary greatly. The larger the subdivision number, the more difficult it is to control the accuracy; and the stepper motor has large vibration and noise when rotating at low speed.
3. Torque motor
The so-called torque motor is a flat multi-pole permanent magnet DC motor. The armature has more slots, commutator segments and series conductors to reduce torque ripple and speed pulsation. The torque motor has two kinds of DC torque motor and AC torque motor.
Among them, the DC torque motor has a small self-inductance reactance, so the responsiveness is very good; its output torque is proportional to the input current, independent of the speed and position of the rotor; it can be directly connected to the load at a low speed when it is close to the locked state. Without gear reduction, a high torque-to-inertia ratio can be generated on the shaft of the load, and system errors due to the use of the reduction gear can be eliminated.
AC torque motors can be divided into synchronous and asynchronous. Currently, squirrel-cage asynchronous torque motors are used, which have the characteristics of low speed and large torque. Generally, an AC torque motor is often used in the textile industry, and its working principle and structure are the same as those of a single-phase asynchronous motor. However, since the squirrel-cage rotor has a large electrical resistance, its mechanical characteristics are soft.
4. Switched reluctance motor
Switched reluctance motor is a new type of speed-regulating motor. Its structure is extremely simple and sturdy, its cost is low, and its speed regulation performance is excellent. It is a strong competitor of traditional control motors and has strong market potential. However, there are also problems such as torque ripple, running noise and vibration, and it takes time to optimize and adapt to the actual market application.
5. Brushless DC motor
Brushless DC motor (BLDCM) is developed on the basis of brushed DC motor, but its driving current is uncompromising AC; brushless DC motor can be divided into brushless speed motor and brushless torque motor. . Generally, there are two kinds of driving currents of a brushless motor, one is a trapezoidal wave (generally “square wave”), and the other is a sine wave. Sometimes the former is called DC brushless motor, the latter is called AC servo motor, and it is also a kind of AC servo motor.
In order to reduce the moment of inertia, brushless DC motors usually adopt a “slender” structure. Brushless DC motors are much smaller in weight and volume than brushed DC motors, and the corresponding moment of inertia can be reduced by 40% to 50%. Due to the processing of permanent magnet materials, the general capacity of brushless DC motors is below 100 kW.
The motor has good linearity of mechanical characteristics and adjustment characteristics, wide speed range, long life, easy maintenance and low noise, and there is no series of problems caused by brushes. Therefore, this kind of motor has great control system. Application potential.
Two: Motor model parameters: Motor model is a code that is easy to use, design, manufacturing and other departments to carry out business contacts and simplify the description of product names, specifications, types and other technical documents. The following is a description of the meaning of the motor model.
A, motor model composition and meaning
It consists of four sub-sections: motor type code, motor characteristic code, design serial number and excitation mode code.
1. The type code is a Chinese phonetic alphabet used to characterize various types of motors. such as:
Asynchronous motor Y synchronous motor T
Synchronous generator TF DC motor Z
DC generator ZF
2. The feature code is to characterize the performance, structure or use of the motor, and is also represented by the Chinese phonetic alphabet. such as:
Flameproof type B means YT for YB axis flow fan
Electromagnetic Brake YEJ Variable Frequency Speed Control YVP
YZD, etc. for variable-speed multi-speed YD cranes.
3. Design serial number refers to the order of motor product design, expressed in Arabic numerals. For the first design of the product, the design serial number is not marked, and the products derived from the series product are marked in the order of design.
For example: Y2 YB2
4. The excitation mode codes are respectively represented by letters, S represents the third harmonic, J represents the thyristor, and X represents the complex excitation.
Such as: Y2– 160 M1 – 8
Y: model, indicating asynchronous motor;
2: design serial number, “2” indicates the product of the improved design on the first basis;
160: the center height is the height from the center of the shaft to the plane of the base;
M1: frame length specification, M is medium, wherein footnote “2” is the second specification of M-type core, and “2” type is longer than “1” type core;
8: The number of poles, “8” refers to the 8-pole motor.
Such as: Y 630-10 / 1180
Y represents an asynchronous motor;
630 represents power 630KW;
10 pole, stator core outer diameter 1180MM.
B. The specification code is mainly expressed by the center height, the length of the base, the length of the core, and the number of poles.
1. The center height refers to the height from the motor shaft center to the bottom angle of the base; according to the height of the center, the motor can be divided into four types: large, medium, small and miniature.
H is a micromotor in the range of 45mm~71mm;
H is a small motor from 80mm to 315mm;
H is a medium-sized motor at 355mm~630mm;
H is a large motor at 630 mm or more.
2. The length of the base is indicated by international common letters:
3. The length of the core is expressed by the Arabic numerals 1, 2, 3, 4, and , respectively, from long to short.
4, the pole number is divided into 2 poles, 4 poles, 6 poles, 8 poles and so on.
C. The special environment code has the following provisions:
Special environment code
“High” original G
Ship (“sea”) with H
Household “outside” with W
Chemical anti-corruption F
Wet tropical TH
Dry tropical TA
D. The supplementary code is only applicable to motors with supplementary requirements.
The meanings of the motor codes of the model number YB2-132S-4 H are:
Y: product type code, indicating asynchronous motor;
B: Product feature code, indicating explosion-proof type;
2: Product design serial number, indicating the second design;
132: The center of the motor is high, indicating that the distance from the axis to the ground is 132 mm;
S: the length of the motor base, expressed as a short base;
4: pole number, indicating 4-pole motor;
H: Special environmental code, indicating the marine motor.
Through the above detailed description of the motor model, I believe that the product type, the type, characteristics, design number, motor specifications and the environment it uses can be known.