An electric motor is an electrical device that converts electrical energy into mechanical energy, and can reuse the mechanical energy to generate kinetic energy to drive other devices. There are many types of motors, but they can be roughly divided into AC motors and DC motors for different occasions.
The advantage of a DC motor is that it is relatively simple in speed control. It only needs to control the voltage to control the speed. However, this type of motor is not suitable for operation in high temperature, flammable and other environments, and because the motor needs to use carbon brushes as a Commutator components (brush motors), so it is necessary to regularly clean up the dirt generated by carbon brush friction. A brushless motor is called a brushless motor. Compared with a brush, a brushless motor is less power-saving and quieter because of the less friction between the carbon brush and the shaft. The production is more difficult and the price is higher. AC motors can be operated in high temperature, flammable and other environments, and do not need to clean carbon brush dirt regularly, but it is difficult to control the speed, because controlling the speed of the AC motor requires controlling the frequency of the AC (or using induction The motor uses the method of increasing the internal resistance to reduce the motor speed at the same AC frequency), and controlling its voltage will only affect the torque of the motor. Generally, the voltage of civil motors is 110V and 220V. In industrial applications, there are also 380V or 440V.
working principle
The principle of rotation of the motor is based on John Ambrose Fleming's left-hand rule. When a wire is placed in a magnetic field, if the wire is energized, the wire will cut the magnetic field line and move the wire. The electric current enters the coil to generate a magnetic field, and the magnetic effect of the electric current is used to make the electromagnet continuously rotate in the fixed magnet, which can convert electrical energy into mechanical energy. It interacts with a permanent magnet or a magnetic field generated by another set of coils to generate power. The principle of a DC motor is that the stator does not move, and the rotor moves in the direction of the force generated by the interaction. The AC motor is the stator winding coil is energized to generate a rotating magnetic field. The rotating magnetic field attracts the rotor to rotate together. The basic structure of a DC motor includes "armature", "field magnet", "snumeric ring", and "brush".
Armature: A soft iron core that can rotate around an axis is wound with multiple coils. Field magnet: A powerful permanent magnet or electromagnet that generates a magnetic field. Slip ring: The coil is connected to two semi-circular slip rings at about both ends, which can be used to change the direction of the current as the coil rotates. Every half a turn (180 degrees), the direction of current on the coil changes. Brush: Usually made of carbon, the collector ring is in contact with the brush in a fixed position to connect to the power source.
Basic structure
There are many types of motors. In terms of basic structure, its composition is mainly composed of stator and rotor.
The stator is stationary in the space, while the rotor can rotate around the shaft and is supported by bearings.
There will be a certain air gap between the stator and the rotor to ensure that the rotor can rotate freely.
The stator and the rotor are wound with coils, and current is applied to generate a magnetic field, which becomes an electromagnet. One of the stator and the rotor can also be a permanent magnet.
The following are all called motors
Classified by power supply:
name
characteristic
DC motor
Use permanent magnets or electromagnets, brushes, commutators and other components. The brushes and commutators continuously supply the external DC power supply to the coil of the rotor, and change the direction of the current in time, so that the rotor can follow the same direction Continue to rotate.
AC motor
The alternating current is passed through the stator coil of the motor, and the surrounding magnetic field is designed to push the rotor at different times and different positions to make it continue to run
*Pulse motor
The power source is processed by a digital IC chip and turned into a pulse current to control the motor. A stepping motor is a kind of pulse motor.
Classified by structure (both DC and AC power supplies):
name
characteristic
Synchronous motor
It is characterized by constant speed and no need for speed regulation, low starting torque, and when the motor reaches the running speed, the speed is stable and the efficiency is high.
Asynchronous motor
Induction motor
It is characterized by simple and durable structure, and can use resistors or capacitors to adjust the speed and forward and reverse rotation. Typical applications are fans, compressors, and air conditioners.
*Reversible motor
Basically the same structure and characteristics as the induction motor, it is characterized by a simple brake mechanism (friction brake) built into the tail of the motor. Its purpose is to achieve instant reversible characteristics by adding frictional load and reduce the effect of the induction motor. The amount of over-rotation generated by the force.
Stepping motor
It is characterized by a kind of pulse motor, a motor that rotates gradually at a certain angle. Because of the open-loop control method, it does not need a feedback device for position detection and speed detection to achieve precise position and speed control, and Good stability.
Servo motor
It is characterized by precise and stable speed control, fast acceleration and deceleration response, rapid action (fast reverse, rapid acceleration), small size and light weight, high output power (ie high power density), high efficiency, etc., and is widely used in position and speed control superior.
Linear motor
It has a long-stroke drive and can exhibit high-precision positioning capabilities.
other
Rotary Converter, Rotating Amplifier, etc.
Use purpose
Typical induction motors are widely used
There are many electric uses, ranging from heavy industries to small toys. Different types of electric motors are selected in different environments. Here are some examples: wind-making equipment, such as electric fans, electric toy cars, boats and other elevators, elevators powered by electricity, such as underground railways, tram factories and hypermarkets Electric automatic doors, electric rolling shutters, and people's livelihood supplies on transport belt buses
Optical drive, printer, washing machine, water pump, disk drive, electric razor, tape recorder, video recorder, CD turntable, industrial and commercial use
Fast elevator working machine (such as: machine tool) textile machine mixer.
The principle of a motor and a generator is basically the same, and the direction of energy conversion is different. The generator converts mechanical energy and kinetic energy into electrical energy through a load (such as water power, wind power). If there is no load, the generator will not have current flowing out. The cooperation of electric motors, power electronics, and micro-controllers has formed a new discipline called motor control. Before using the motor, you need to know whether the power source is DC or AC. If it is AC, you also need to know whether it is three-phase or single-phase. Connecting the wrong power supply will cause unnecessary losses and dangers. After the motor is rotated, if the load is not connected or the load is light so that the motor speed is fast, the induced electromotive force is stronger. At this time, the voltage across the motor is the voltage provided by the power supply minus the induced voltage, so the current is weakened. If the load of the motor is heavy and the rotation speed is slow, the relative induced electromotive force is smaller. Therefore, the power supply needs to provide a larger current (power) to output/work corresponding to the larger power required.
The market in the field of industrial motors is changing, and many industrial motor predators rely on their strong strength to deploy the global market. Business Opportunity Trading Network introduces the world's top ten electric motor companies in detail.
Siemens
From building technology and automation equipment for manufacturers and construction companies, to imaging and diagnostic systems for hospitals, and electric motors for industrial and mobile applications, Siemens seems to have it everywhere. Siemens has been one of the world's leading companies in the motor manufacturing industry for more than 150 years.
Toshiba Industrial Machine System
As a major supplier of various products and solutions in the world, Toshiba Industrial Machinery Systems entered the motor industry in 1970 and has formed a significant tradition of producing some of the most reliable and powerful motors in the global market. This company offers a variety of low- and medium-voltage motors, which have new standards in efficiency and durability.
ABB Group
With a history of more than 130 years of technological innovation, ABB Group has become a world leader in the fields of electrification products, industrial automation and power grids, robotics and sports. The company serves customers in the global public utilities, industry, transportation and infrastructure sectors.
Nidec
It is Japan's leading motor and control equipment manufacturer, mainly producing industrial, household appliances and consumer products. Emerson Power’s previously announced acquisition of its power generation, motor and drive businesses has been completed. After the acquisition, the company has a solid business foundation, obvious brand advantages, and a good customer base, mainly in the northern region. In addition to the United States and Europe, the company agreed to establish a joint venture with the French automaker PSA Group and invested 261 million US dollars to produce motors in France for domestic and foreign sales.
Rockwell Automation
Roxwell Automation was founded in 1903 with an investment of 1,000 US dollars. Since then, the US industrial automation supplier has become one of the leaders in global automation technology, which has proven to be a successful example. In the past ten years, the company's investment in globalization and technology has brought its target market to more than US$90 billion.
AMETEK
As a world-class organization, AMETEK is committed to providing customers with important solutions to the most complex challenges through unique technological innovation. Atimek's subsidiary company Atimek's Advanced Motion Solutions (AMS) is located in Kent, Ohio, and provides DC motors, controllers/drives, fans, pumps, precision controlled blowers, and custom engineered linear motion systems.
Regal Beloit
"Energy-saving and environmental protection" is a global energy-saving technology that meets customer needs by providing world-class products and services. Its motors and power transmission systems have been successful. Its Genteq brand DC motors cover almost all household air conditioning variable speed equipment in the United States, and its Marathon motors, Leeson and GE commercial motors have also been widely used.
Dechang Group
Over the past 50 years, Johnson Group has become a global leader in motors, motion sub-systems, actuators and related electromechanical components in vertical fields and businesses in multiple industries. Application-specific technology and technical leadership are the key driving forces that make Johnson a global leader. Johnson provides the largest set of engineering motors and motion systems, which can be standardized, mass-produced or customized to meet the needs of strategic departments and key customers.
Franklin Electric
From a small motor manufacturer to a world-leading supplier of fuel and water delivery systems and parts, Franklin Electric is actively and comprehensively expanding its business, making it one of the best motor manufacturers in the world. Franklin Electric serves customers in commercial, residential, industrial, agricultural, municipal and fuel applications worldwide.
Allied Motion
Erid Mott has become a leading manufacturer of precision motion control products and solutions due to his knowledge of electromagnetic, mechanical and electronic motion technology. Its growth strategy is to become a leader in selected target markets, use its expertise to develop precision motion solutions, and use various joint motion technologies to create higher-value solutions for customers.
