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The advantage of DCMotor is that the speed control is relatively simple, and the speed can be controlled only by controlling the voltage. However, this kind of motor is not suitable for operating in high temperature and flammable environment, and carbon brush is needed as a component of converter (brushed motor) in the motor, so the dirt generated by friction of carbon brush needs to be cleaned regularly. Brushless motor is called brushless motor. Compared with brushes, brushless motors save energy and are quieter because there is less friction between carbon brushes and shafts. It is difficult to make and expensive. The AC motor can operate in high temperature, flammable and other environments, and it is not necessary to clean the dirt on the carbon brush regularly, but it is difficult to control the rotating speed, because controlling the rotating speed of the AC motor requires controlling the frequency of alternating current (or using an induction motor to reduce the rotating speed by increasing the internal resistance at the same frequency of alternating current), and controlling its voltage will only affect the torque of the motor. Generally, there are two voltages for civil motors: 1 10V and 220V, and 380V or 440V for industrial applications.
principle
The rotation principle of the motor is based on Fleming's left-hand rule. Put the wire in a magnetic field. If the wire is energized, it will cut the magnetic field lines and make the wire move. A device that current enters the coil to generate a magnetic field, and the electromagnet rotates continuously in the fixed magnet by using the magnetic effect of current, can convert electrical energy into mechanical energy. The principle that the DC motor interacts with the magnetic field generated by the permanent magnet or another set of coils to generate power is that the stator does not move and the rotor moves in the direction of the force generated by the interaction. Ac motor is a rotating magnetic field generated by applying alternating current to the stator winding coil, and the rotating magnetic field attracts the rotor to rotate together. The basic structure of DC car includes? Armature? 、? Magnetic field magnet? 、? Collector ring? 、? Brush? .
Armature: a soft iron core that can rotate around an axis and is wound with multiple coils. Magnetic field magnet: A powerful permanent magnet or electromagnet that generates a magnetic field. Slip ring: Two semicircular slip rings are connected to about two ends of the coil. The slip rings rotate with the coil and can be used to change the direction of current. Every half turn (180 degrees), the current direction on the coil changes once. Brush: usually made of carbon, the collector ring contacts the brush at a fixed position to connect the power supply.
Basic structure
There are many kinds of motors. In terms of basic structure, they are mainly composed of stator and rotor.
The stator is stationary in 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 rotor are wound with coils, and when current is applied to generate a magnetic field, it becomes an electromagnet. One of the stator and the rotor may also be a permanent magnet.
Development history
1835, American blacksmith ThomasDavenport made the world's first applied motor that can drive a small tram. 1In the early 1970s, ZenobeTheophileGamme, a Belgian electrical engineer, invented the world's earliest commercialized motor. 1888, the famous American inventor Nicholas? Tesla applied Faraday's electromagnetic induction principle to invent the AC motor, which is the induction motor. 1845, the British physicist Wheatstone applied for the patent of linear motor, but its principle was not taken seriously until 1960, and a practical linear motor was designed and widely used in industry. 1902, Swedish engineer Danielson invented the synchronous motor by using the rotating magnetic field concept of Tesla induction motor. 1923, the scot JamesWeirFrench invented the three-phase variable reluctance stepping motor. 1962, with the help of Hall element, the practical DC brushless motor finally came out. In the1980s, practical ultrasonic motors began to appear.
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