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2023
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Thoroughly dissecting the detailed structure of the three-phase asynchronous motor
Author:
The three-phase asynchronous motor is composed of two basic parts: a fixed stator and a rotating rotor. The rotor is installed in the inner cavity of the stator and is supported on two end covers by bearings. In order to ensure that the rotor can rotate freely in the stator, there must be a gap between the stator and the rotor, which is called an air gap. The air gap of the motor is a very important parameter, and its size and symmetry have a great influence on the performance of the motor.
Motor accessories refer to the original parts of the motor assembled by the motor manufacturer. The parts that are damaged and replaced due to improper use or wear are called motor accessories. The classification of motor accessories can probably be classified according to the components of the motor, which can probably be divided into motor stator, motor rotor, stator winding, motor housing, end cover, motor fan blade, bearing and other parts.
Motor stator
The motor stator is an important part of motors such as generators and starters. The stator is an important part of the motor. The stator is composed of three parts: stator core, stator winding and frame. The main function of the stator is to generate a rotating magnetic field, and the main function of the rotor is to be cut by the magnetic line in the rotating magnetic field to generate (output) current.
motor rotor
The motor rotor is also a rotating component in the motor. The motor is composed of two parts: rotor and stator. It is a conversion device used to realize electrical energy and mechanical energy and mechanical energy and electrical energy. Motor rotor is divided into motor rotor and generator rotor.
stator winding
Stator windings can be divided into two types: centralized and distributed, depending on the shape of the coil winding and the way of embedded wiring. The winding and embedding of the concentrated winding are relatively simple, but the efficiency is low and the running performance is poor. At present, most of the AC motor stators are applied distributed windings. According to different models, models and process conditions of coil embedding, the motors are designed with different winding types and specifications, so the technical parameters of the windings are also different.
Motor housing
The motor housing generally refers to the external casing of all electrical motor equipment. The motor housing is the protection device of the motor, which is made of silicon steel sheet and other materials with stamping and deep drawing process. Coupled with the surface of the rust and spray process can be a good protection of the internal motor equipment. Main function: dustproof, anti-noise, waterproof.
End cap
The end cover is a rear cover installed behind the motor and other enclosures, commonly known as "end cover", which is mainly composed of a cover, a bearing, and an electric brush. Whether the end cover is good or bad directly affects the quality of the motor. A good end cover, mainly from its heart-brush, its role is to drive the rotation of the rotor, this part is the key part.
Motor fan blade
The motor fan blades are generally located at the tail of the motor and are used for ventilation and cooling of the motor. They are mainly used at the tail of the AC motor or placed in the special ventilation ducts of the DC and high-voltage motors. The fan blades of explosion-proof motors are generally made of plastic materials.
According to the material classification: motor blades can be divided into three kinds, and plastic blades, cast aluminum blades, cast iron blades.
Bearing
Bearings are an important part of contemporary machinery and equipment. Its main function is to support the mechanical rotating body, reduce the friction coefficient during its movement, and ensure its rotation accuracy.
Rolling bearings are generally composed of four parts: outer ring, inner ring, rolling element and cage. Strictly speaking, it is composed of six parts: outer ring, inner ring, rolling element, cage, seal and lubricating oil. Mainly has the outer ring, the inner ring, the rolling element can be determined as a rolling bearing. According to the shape of the rolling body, rolling bearings are divided into two categories: ball bearings and roller bearings.
The stator is composed of stator core, stator winding, frame and end cover. The main function of the frame is to support the various parts of the motor, so it should have sufficient mechanical strength and rigidity, usually made of cast iron.
In order to reduce eddy current and hysteresis losses, the stator core is made of 0.5mm thick silicon steel sheets coated with insulating paint. There are many evenly distributed slots on the inner circumference of the core, and the stator windings are embedded in the slots.
The stator windings are distributed in the slots of the stator core. The stator windings of small motors are usually wound with enameled wire. The three-phase windings are separated from each other by 120 ° in the inner circumferential space of the stator. There are six outlet terminals, which are respectively led to the terminals of the motor junction box. on.
The three-phase stator windings may be connected in a star or delta shape. The connection method is determined according to the rated voltage of the motor and the three-phase power supply voltage. Usually, the first ends of the three windings are represented by U1, V1 and W1 respectively, and the ends are represented by U2, V2 and W2.
The rotor is the rotating part of the motor, including the rotor core, the rotor winding and the rotating shaft.
1. Rotor core
Function: part of the motor magnetic circuit and place the rotor winding. Generally, 0.5mm thick silicon steel sheet is punched and laminated. The outer circle of the silicon steel sheet is punched with evenly distributed holes to place the rotor winding.
2. Rotor winding
The function is to cut the stator rotating magnetic field to generate induced electromotive force and current, and form electromagnetic torque to make the motor rotate. According to the different structure is divided into squirrel cage rotor and wound rotor
Squirrel-cage rotor: If the rotor core is removed, the entire winding looks like a squirrel cage, so it is called cage winding. Small cage motors are made of cast aluminum rotor windings, and copper bars and copper end rings are welded for motors above 100KW.
Wound rotor: The wound rotor winding is similar to the stator winding, and it is also a symmetrical three-phase winding. It is generally connected into a star shape. The three outgoing lines are connected to the three collector rings (slip rings) of the rotating shaft, and then through the brush Connect with the external circuit.
3. Shaft
Used to transmit torque and support the weight of the rotor, generally made of medium carbon steel or alloy steel.
(III) Other Accessories
End cover, bearing, bearing end cover, fan.
Motor,Accessories
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