| Compared with single-phase asynchronous motors, three-phase asynchronous motors have better running performance! | |
| 2020/11/13 | |
| Compared with single-phase asynchronous motors, three-phase asynchronous motors have better running performance and can save various materials. According to the different rotor structure, three-phase asynchronous motors can be divided into two types: cage type and winding type. The cage rotor asynchronous motor is simple in structure, reliable in operation, light in weight, low in price, and widely used. Its main disadvantage is the difficulty in speed regulation. The rotor and stator of the wound three-phase asynchronous motor are also provided with three-phase windings and connected to an external rheostat through slip rings and brushes. Adjusting the resistance of the rheostat can improve the starting performance of the motor and adjust the speed of the motor. The working principle of three-phase asynchronous motor When a symmetrical three-phase alternating current is applied to the three-phase stator windings, a rotating magnetic field that rotates clockwise along the inner circular space of the stator and rotor at a synchronous speed n1 is generated. Since the rotating magnetic field rotates at a speed of n1, the rotor conductor is stationary at the beginning, so the rotor conductor will cut the stator rotating magnetic field to generate induced electromotive force (the direction of the induced electromotive force is determined by the right-hand rule). Since both ends of the rotor conductor are short-circuited by the short-circuit ring, under the action of the induced electromotive force, an induced current that is basically the same as the direction of the induced electromotive force will be generated in the rotor conductor. The current-carrying conductor of the rotor is subjected to electromagnetic force in the stator magnetic field (the direction of the force is determined by the left-hand rule). The electromagnetic force generates electromagnetic torque on the rotor shaft and drives the rotor to rotate along the direction of the rotating magnetic field. Chain winding Chain winding is composed of single-layer coil elements with the same shape and width. It is named after each coil at the winding end is like a set of chain rings. Special attention should be paid to the single-layer chain winding that its coil pitch is odd, otherwise the winding will not be arranged. Cross-chain windings When the number of slots per pole per phase 9 is an odd number greater than 2, the chain windings cannot be arranged and arranged. In this case, cross windings with single and double coils are required. All coils of the concentric winding in the same pole phase group surround the same circle center. When the number of slots per phase per stage Q is an even number greater than 2, the cross concentric winding can be adopted. The content of the article comes from the Internet, if you have any questions, please contact us! |
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