English English
High rpm motor dc electric motor

Индияда электр унаалары үчүн жогорку айланма мотор туруктуу электр кыймылдаткычын өндүрүүчүлөр

Индияда электр унаалары үчүн жогорку айланма мотор туруктуу электр кыймылдаткычын өндүрүүчүлөр

1、 Difference between synchronous motor and asynchronous motor: (both belong to AC motor)

Structure: the stator windings of synchronous motor and asynchronous motor are the same, and the main difference lies in the structure of rotor. The rotor of the synchronous motor has a DC excitation winding, so it needs an external excitation power supply to introduce current through the slip ring; The rotor of asynchronous motor is a short-circuit winding, which generates current by electromagnetic induction (also known as induction motor). In contrast, synchronous motors are more complex and costly.

Application: synchronous motors are mostly used in large generators. The asynchronous motor is almost all used in motor occasions. The efficiency of synchronous motor is slightly higher than that of asynchronous motor. When selecting motors above 2000kW, it is generally necessary to consider whether to select synchronous motor.

2、 Single phase asynchronous motor and three-phase asynchronous motor:

Single motor: when the single-phase sinusoidal current passes through the stator winding, the motor will generate an alternating magnetic field. The strength and direction of the magnetic field will change sinusoidally with time, but it is fixed in the spatial direction, so it is also called as alternating pulsating magnetic field. This alternating pulsating magnetic field can be decomposed into two rotating magnetic fields which are opposite to each other at the same speed and direction of rotation. When the rotor is stationary, the two rotating magnetic fields generate two torques of equal size and opposite direction in the rotor, making the synthetic torque zero, so the motor cannot rotate. When we use an external force to make the motor rotate in a certain direction (such as clockwise rotation), the motion of the cutting magnetic line of force between the rotor and the rotating magnetic field in the clockwise rotation direction becomes smaller; The cutting magnetic line of force motion between the rotor and the rotating magnetic field in the counterclockwise rotation direction becomes larger. In this way, the balance is broken, the total electromagnetic torque generated by the rotor will no longer be zero, and the rotor will rotate along the driving direction. Generally, according to the characteristics of motor starting and operation mode, single-phase asynchronous motor is divided into five types: single-phase resistance starting asynchronous motor, single-phase capacitor starting asynchronous motor, single-phase capacitor starting and operating asynchronous motor, and single-phase shaded pole asynchronous motor.

Difference: 380V three-phase power supply is used for three-phase asynchronous motor, and 220V power supply is used for single-phase motor, which is of small power, and the maximum power is only 2.2kW. Compared with the three-phase motor with the same speed and power, the single motor has low efficiency, low power factor, poor running stability, large volume and high cost. However, due to the convenience of single-phase power supply and convenient speed regulation, it is widely used in electric tools, medical devices, household appliances, etc.

Индияда электр унаалары үчүн жогорку айланма мотор туруктуу электр кыймылдаткычын өндүрүүчүлөр

3、 Brushless DC motor

1. Brushless DC motor:

Brushless DC motor is a kind of permanent magnet synchronous motor, but not a real DC motor. Brushless DC motor does not use mechanical brush device, adopts square wave self-control permanent magnet synchronous motor, uses Hall sensor to replace carbon brush commutator, and uses neodymium iron boron as permanent magnet material of rotor. It has great advantages over conventional DC motor in performance, and is the most ideal speed regulating motor today. The DC brushless motor is composed of the motor body and the driver. A position sensor is installed in the motor to detect the polarity of the motor rotor. The driver is composed of power electronic devices and integrated circuits. Its function is to receive the start, stop and braking signals of the motor to control the start, stop and braking of the motor; It receives the position sensor signal and the forward and reverse signals to control the on-off of each power tube of the inverter bridge and generate continuous torque; Receive speed command and speed feedback signal to control and adjust speed; Provide protection and display, etc.

мүнөздүү:

 comprehensively replace DC motor speed regulation, frequency converter + variable frequency motor speed regulation, asynchronous motor + reducer speed regulation;  

 it has all the advantages of traditional DC motor, and cancels the carbon brush and slip ring structure;  

 it can operate at low speed and high power, and it can save the heavy load directly driven by the reducer;  

 small size, light weight and large output;  

 excellent torque characteristics, good middle and low speed torque performance, large starting torque and small starting current;  

 stepless speed regulation, wide speed regulation range and strong overload capacity;  

 soft start and soft stop, with good braking characteristics, the original mechanical braking or electromagnetic braking device can be omitted;  

 high efficiency. The motor itself has no excitation loss and carbon brush loss, eliminating multi-stage deceleration consumption. The comprehensive power saving rate can reach 20%~60%. Only power saving can recover the purchase cost one year;  

 high reliability, good stability, strong adaptability and simple maintenance;  

 resistant to turbulence and vibration, low noise, small vibration, smooth operation and long service life;  

 no radio interference, no spark, especially suitable for explosive places, explosion-proof;  

 ladder wave magnetic field motor and positive rotating wave magnetic field motor can be selected as required.

Индияда электр унаалары үчүн жогорку айланма мотор туруктуу электр кыймылдаткычын өндүрүүчүлөр

2. Brushless DC motor and brushless DC motor

Brushless DC motor and DC motor are two concepts. Although the name of Brushless DC motor is DC, it is not a DC motor. From the classification point of view, DC motor is a class, while brushless DC motor belongs to synchronous motor.

(1) Advantages of brushless motor

 no brush, low interference: without the electric spark generated by the brush motor during operation, the interference of electric spark to the remote control radio equipment is greatly reduced.

 low noise and smooth operation: without the electric brush, the friction is greatly reduced, the operation is smooth, the calorific value is low, the efficiency is high, and the noise is low, which is a great support for the stability of the model operation.

 long service life and low maintenance cost: the wear of brushless motor is mainly on the bearing. From the mechanical point of view, brushless motor is almost a maintenance free motor. When necessary, it only needs to do some dust removal maintenance.

However, the brush motor has excellent low-speed torque performance and large torque, which can not be replaced by the brushless motor

(2) In terms of trend, brushless reduction motors may replace brush reduction motors

 scope of application: brushless motors are usually used in equipment with high control requirements and high speed, such as aircraft models, precision instruments and other equipment that strictly control the motor speed and reach a very high speed; Usually, power equipment uses brush motors, such as hair dryers, factory motors, household range hoods, etc;

 service life: the service life of brushless motor is usually in the order of tens of thousands of hours, which mainly depends on the different bearings; Generally, the continuous working life of brush motor is hundreds to more than 1000 hours, and the carbon brush needs to be replaced when it reaches the service limit;

 use effect: brushless motor is usually controlled by digital frequency conversion, with strong controllability. It can be easily realized from a few revolutions per minute to tens of thousands of revolutions per minute. After the carbon brush motor is started, the working speed is constant, and the speed regulation is not easy. The series motor can also reach 20000 rpm, but the service life will be relatively short.

 energy saving and environmental protection: relatively speaking, brushless motor controlled by frequency conversion technology will save a lot of energy than series excited motor. The most typical are frequency conversion air conditioners and refrigerators.

 maintenance: the carbon brush motor needs to replace the carbon brush, while the brushless motor has a long service life, and daily maintenance is basically unnecessary.  

 noise: it has nothing to do with whether it is a brush motor. It mainly depends on the coordination of bearings and internal components.

3. Brushless DC motor and AC motor

Brushless DC motor, the stator is a rotating magnetic field, dragging the rotor magnetic field to rotate;

AC synchronous motor is also a stator rotating magnetic field dragging the rotor magnetic field to rotate;

Индияда электр унаалары үчүн жогорку айланма мотор туруктуу электр кыймылдаткычын өндүрүүчүлөр

The difference between them is that the reasons for the rotation of the rotating magnetic field are different: (1) for AC synchronous motor, the reason for the rotation of the stator magnetic field is the three-phase symmetrical alternating current that lags behind each other by 120 degrees, and the rotation of the stator magnetic field is the change speed of the alternating current; (2) The DC motor is formed by the change of the actual position connected with the coil due to the constant voltage of the DC power supply, and the change of the actual position connected with the coil is the speed of rotor rotation; In this way, their speed regulation methods are different: (1) for AC synchronous motors, the reason for the rotation of stator magnetic field is the three-phase symmetrical alternating current that lags behind each other by 120 degrees, and the rotation of stator magnetic field is the change speed of alternating current; As long as the speed of AC change is changed, the motor speed can be changed, that is, variable frequency speed regulation; (2) The DC motor is formed by the change of the actual position of the coil connection with the constant voltage of the DC power supply, and the change of the actual position of the coil connection is only related to the speed of rotor rotation; As long as the rotor speed is changed, the speed can be adjusted, and the rotor speed is directly proportional to the voltage. Changing the voltage can change the speed, that is, voltage regulation.

DC speed regulation does not change the load property of the motor, while AC speed regulation changes the load property; AC speed regulation (frequency conversion), when the frequency is different, the inductive reactance of AC motor is different, and the load property changes accordingly. It is a very unstable system, and it is difficult to realize fine speed regulation. DC speed regulation (voltage transformation) is a very stable system, which is easy to realize fine speed regulation, and the voltage and speed of several millivolts can be distinguished.

Since the excitation of the brushless DC motor comes from the permanent magnet, there is no excitation loss. Since there is no alternating magnetic flux in the rotor, there is neither copper nor iron loss on the rotor, and the comprehensive efficiency is about 10~20% higher than that of the asynchronous motor with the same capacity (depending on the power). Brushless DC motor has the three high characteristics of high efficiency, high torque and high precision. It is very suitable for machinery running continuously for 24 hours. At the same time, it has small volume, light weight, and can be made into various volume shapes. Its product performance exceeds all the advantages of traditional DC motor. It is the most ideal speed regulating motor today.

Comparison: DC motor has excellent starting characteristics and speed regulation characteristics, but the cost is high; AC motor has low cost and convenient power supply, but its starting characteristics and speed regulation characteristics are slightly poor;

4. Brushless DC motor and AC servo motor

Brushless DC motor: the induced back EMF of Brushless DC motor is also trapezoidal wave. The control of Brushless DC motor needs position information feedback. It must have position sensor or adopt sensorless estimation technology to form an automatic speed regulation system. During control, the current of each phase shall also be controlled into square wave as far as possible, and the output voltage of the inverter shall be controlled according to the PWM method of the brush DC motor. In essence, brushless DC motor is also a kind of permanent magnet synchronous motor, and the speed regulation actually belongs to the category of variable voltage and variable frequency speed regulation.

 

 

Индияда электр унаалары үчүн жогорку айланма мотор туруктуу электр кыймылдаткычын өндүрүүчүлөр

AC servo motor: Generally speaking, AC permanent magnet synchronous servo motor has stator three-phase distributed winding and permanent magnet rotor. The waveform of induced electromotive force is sinusoidal, and the applied stator voltage and current should also be sinusoidal. Generally, it is provided by AC variable voltage converter. Permanent magnet synchronous motor (PMSM) control system often adopts automatic control, which also needs position feedback information. It can adopt advanced control methods such as vector control (field oriented control) or direct torque control.  

Difference: square wave and sine wave control lead to different design concepts. Finally, a concept is clarified. The so-called "DC frequency conversion" of Brushless DC motor is actually AC frequency conversion through inverter. Theoretically speaking, brushless DC motor is similar to AC permanent magnet synchronous servo motor and should be classified as AC permanent magnet synchronous servo motor; However, it is customarily classified as a DC motor, because from the perspective of its control and driving power supply and control object, it is also appropriate to call it a "brushless DC motor".

4、 Motor speed regulation

1. DC motor speed regulation:

Rotor circuit series resistance (short-time speed regulation), rotor circuit voltage (widely used, the regulation range is 0-base speed), changing magnetic flux (only increasing speed, above base speed, constant power speed regulation)

(1) Voltage speed regulation: controllable power supply speed regulation, PWM (pulse width modulation) speed regulation (widely used)

Compared with the old controllable DC power supply speed regulation system, PWM speed regulation system has the following advantages:

A. for the PWM speed regulation system with fully controlled devices, the switching frequency of the PWM circuit is high, so the system has wide frequency band, fast response speed and strong dynamic immunity.  

B. due to the high switching frequency, the DC current with small pulsation can be obtained only by the filtering effect of the motor armature inductance. The armature current is easy to be continuous. The system has good low-speed performance, high speed stability accuracy, wide speed regulation range, and small motor loss and heating.  

C. in the PWM system, the power electronic devices of the main circuit work in the switching state, with low loss, high device efficiency and little impact on the AC power grid. There is no "pollution" of the thyristor rectifier to the power grid, and the power factor is high and the efficiency is high.  

D. the main circuit requires less power components, simple circuit and convenient control.  

At present, due to the limitation of device capacity, PWM DC speed regulation system is only used in medium and small power systems. The domestic super power speed regulation also relies on SCR to realize controllable rectification to realize voltage regulation and speed regulation of DC motor.

 Редукторлор жана электр кыймылдаткычтары өндүрүүчүсү

түздөн-түз сиздин почта кутучасына биздин өткөрүү диск эксперт мыкты тейлөө.

Байланышуу

Yantai Bonway Manufacturer Co.ltd

ANo.160 Changjiang Road, Yantai, Shandong, Кытай(264006)

T + 86 535 6330966

W + 86 185 63806647

© 2024 Sogears. Бардык укуктар корголгон.