Basic structure of the motor
1. The structure of a three-phase asynchronous motor consisting of a stator, a rotor and other accessories.
(1) Stator (still part)
1, the stator core
Function: A part of the magnetic circuit of the motor and the stator windings placed on it.
Structure: The stator core is generally formed by laminating and laminating a silicon steel sheet having an insulating layer on the surface of 0.35 to 0.5 mm thick, and has a uniformly distributed groove in the inner circle of the core for embedding the stator winding.
There are several types of stator core slots:
Semi-closed groove: The efficiency and power factor of the motor are higher, but the winding and insulation are more difficult. Generally used in small low voltage motors.
Semi-opening groove: It can be embedded with molded windings, and is generally used for large and medium-sized low-voltage motors. The so-called forming winding, that is, the winding, can be placed in the groove before being insulated.
Open type slot: used to embed the formed winding, the insulation method is convenient, mainly used in high voltage motors.
2, stator winding
Function: It is the circuit part of the motor, which is connected to three-phase alternating current to generate a rotating magnetic field.
Structure: It is made up of three identical windings in which the space is separated by 120° electrical angle and the team is arranged. The coils of these windings are respectively embedded in the slots of the stator according to certain rules.
The main insulation items of the stator windings are as follows: (to ensure reliable insulation between the conductive parts of the windings and the core and reliable insulation between the windings themselves).
(1) Insulation to ground: insulation between the stator winding and the stator core.
(2) Phase-to-phase insulation: insulation between stator windings of each phase.
(3) Turn-to-turn insulation: insulation between turns of each phase stator winding.
Wiring in the motor junction box:
There is a terminal block in the motor junction box. The six wire ends of the three-phase winding are arranged in two rows, and the three terminal blocks in the upper row are numbered 1 to 1 (U1), 2 (V1), and 3 from left to right. (W1), the three wiring piles in the lower row are numbered 6 (W2), 4 (U2), and 5 (V2) from left to right. The three-phase windings are connected in a star connection or a delta connection. All manufacturing and maintenance should be arranged according to this serial number.
3, the base
Function: Fix the stator core and the front and rear end caps to support the rotor, and play the role of protection and heat dissipation.
Construction: The base is usually cast iron, the large asynchronous motor base is usually welded with steel plate, and the base of the micro motor is made of cast aluminum. There is a heat dissipation rib on the outer surface of the closed motor to increase the heat dissipation area. The end caps of the protective motor have ventilation holes at both ends, so that the air inside and outside the motor can be directly convected to facilitate heat dissipation.
