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What is an induction motor?

of the induction motor, also known as “induction motor”, the rotor is placed in rotating magnetic field, under the action of a rotating magnetic field, means for obtaining a rotating torque, and therefore rotation of the rotor. The rotor is rotatable conductor, usually mostly squirrel cage shape. By the electrical engineer Nikola Tesla invented in 1887. It introduces the concept of entry of the induction motor, the inventor, the working principle, the basic structure, mode of operation, the braking mode, asynchronous features, specifications and troubleshooting.

1. Introduction to Induction Motor Motor

of the induction motor, also known as “asynchronous motor (asynchronousmotor)”, i.e. the rotor is placed in rotating magnetic field, under the effect of the rotating magnetic field, a rotating torque is obtained, Then the rotor rotates. The rotor is rotatable conductor, usually mostly squirrel cage shape. The stator of the motor is not rotating part of the main task is to produce a rotating magnetic field. Mechanically rotating magnetic field is not achieved. But to the number of the alternating current through the electromagnet, the pole so as to change the nature of the cycle, it corresponds to a rotating magnetic field. A DC motor as such motors do not have the kind of slip rings or brushes, used according to the alternating currentSingle-phase motors and three-phase motors, such as a single-phase motor used in washing machines, electric fans and the like; the three-phase motor as a power plant equipment.

2. Induction motor inventor

Nikola Tesla (Nikola Tesla, 1856 Nian 7 Yue 10 Ri – January 7, 1943), the Serbian-American inventor , mechanical engineers, electrical engineers. He is considered one of the key promoters of electricity commercialization, and presided over the design of modern alternating current system and best known. On the basis of electromagnetic theory of Michael Faraday discovered on the Tesla has a number of revolutionary invention in the field of electromagnetic fields. 1887 invention of the induction motor, his theoretical work as well as a number of related patents electromagnetism is the cornerstone of modern wireless communications and radio.

3. The operating principle of the induction motor

the rotating magnetic field (rotating at synchronous speed n1) and the relative movement of the rotor winding, the rotor winding the cutting wire by the magnetic induction induced electromotive force generated in the stator, such that currents induced in the rotor winding. Magnetic field and the induced current in the rotor winding, the electromagnetic torque, to rotate the rotor. When the rotational speed of the rotor due to approaching synchronous speed, the induced current decreases, the electromagnetic torque generated decreases accordingly, when the motor is operating in the asynchronous state of the motor, the rotor speed is less than the synchronous speed. In order to describe the difference between the synchronous speed n and the rotor speed n1, the introduction of the slip (slip).

4. The basic structure of the induction motor

The basic structure of the single-phase induction motor

single-phase induction motor is the only single-phase AC power supply to the motor. Single-phase induction motor includes a stator, a rotor, bearings, housing, end caps and the like. The stator core by the winding belt and the base composition. A laminated core made of silicon steel tank, loaded groove embedded space Alternaria two main windings 90 ° electric angle (also called run winding) and a secondary winding (also called starting secondary winding of coils). After the primary winding connected to AC power, auxiliary winding S series centrifugal switch or starting capacitor, the run capacitor, etc., then access to power. Aluminum rotor cage rotor, the laminated core which is cast into the groove aluminum core, and cast end ring together with the short-circuited squirrel-cage rotor bar type.

single-phase induction motor is divided into single phase resistance start induction motor, capacitor start single-phase induction motor, the single-phase asynchronous motors and single-phase two-value capacitor induction motor.

The basic structure of the three-phase induction motor

major phase asynchronous motor stator and rotor, bearing components. Mainly by the stator core, three-phase windings, base, end caps.

The stator core typically made of silicon steel having an insulating layer by 0.35 to 0.5 mm thick surface laminated is made of punched slots are evenly distributed within the circle of the core, a stator winding for Embedding.

by a three-phase winding in the space Alternaria electrical angle of 120 °, said band winding arrangement are connected in exactly the same structure, each of these coil winding according to certain rules are embedded in each slot of the stator. Its role is to pass into a three-phase alternating current, a rotating magnetic field.

base is usually cast iron, is generally large asynchronous motor frame welded into the steel sheet, micromotor cast aluminum base member, whose role is fixed to the stator core support the rotor and the front cover, and from protective action, heat and the like.

stands outside hermetic motor with cooling ribs to increase the cooling area, both ends of the base motor protection cap vents are opened, so that air directly outside the convection motor to facilitate cooling. The main rotor from the fixed end cap, support and protection.

is mainly composed of a rotor core and windings. The rotor core and the stator as the materials used, the silicon steel sheet thickness of 0.5 mm stamped, laminated is made of silicon steel sheets punched with holes distributed uniformly cylindrical, and is disposed to the rotor windings. Usually within the stator core to the red circle backward punching silicon steel rotor core. Usually small induction motor rotor core press directly mounted on the shaft, the large and medium-sized induction motor rotor core (rotor diameter of 300 to 400 mm) and the rotor holder by means of pressure on the shaft.

into the rotor winding squirrel-cage rotor and a wound rotor. (1) cage rotor: a rotor winding end ring inserted into the rotor slots and a plurality of bars of two ring components. If the rotor core is removed, the entire shape like a squirrel cage winding, so that the cage winding. Cast aluminum cage motor small rotor winding, the motor for more than 100KW copper bars and end rings welded copper. Squirrel cage rotor is divided into: rotor impedance, single squirrel-cage type rotor, the double squirrel-cage rotors, rotor several deep groove, starting torque and other characteristics are different. (2) a wound rotor: similar wound rotor winding and the stator winding, three-phase winding is a symmetrical, generally connected in star, the three slip ring three line heads to the rotary shaft, and then through a brushCoupled with an external circuit.

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