Three-phase AC synchronous motor or asynchronous motor (hereinafter referred to as three-phase AC motor), when the stator winding is connected to the power supply, that is, a rotating magnetic field is generated, so that, for asynchronous motor, the rotor is induced current due to electromagnetic induction; For synchronous motor rotor need to apply excitation current. The rotor of the motor is magnetized and rotates by electromagnetic attraction. The synchronous motor rotates according to the synchronous speed after excitation; The rotation of the asynchronous motor produces slip.
The generation of the motor rotating magnetic field gravity is because the magnetic field line has the shortest characteristics, the electromagnetic force makes the motor run on the electromagnetic center line, that is, the electromagnetic force of the motor stator and rotor acts in the radial direction, so that they balance each other, and will not produce axial magnetic force.
Why does the motor produce axial force during operation?
The electromagnetic center line of the motor is the reference line for the connection between the motor shaft and the coupling of the driven mechanical equipment. However, since there is no electromagnetic centerline mark in the design and manufacture of the motor, the installation drawing and calibration size provided by the random file provided when the motor is installed and the coupling is based on the mechanical center of the design.
In this way, the motor will inevitably appear in the actual operation because the mechanical center line and the electromagnetic center line do not coincide and appear offset, that is, the installation of the motor, the coupling error, the axial force generated. The direction of the axial force is to produce a push or pull axial force on the driven mechanical equipment, resulting in damage to the bearings or the whole machine of the motor and the driven mechanical equipment.
For the increased safety type non-secondary excitation synchronous motor, its factors are more, so from the point of view of process manufacturing, improve the punching quality; Reduce the chip burr; Strictly follow the process discipline of the number of laminated pieces and laminated pressure to ensure the length of stator and rotor core; Eliminating artificial installation and assembly errors, while requiring enterprise technical workers to have high technical quality and fine assembly skills, is to reduce the axial force of the process guarantee. In addition, the designer must be proficient in the manufacturing process, product assembly process, and overall consideration in the structural design and according to the motor steering, fan layout, chute direction and other inherent factors generated by the magnitude and direction of the axial force, so that they can offset each other or reduce to a minimum degree. At the same time, the product assembly technicians must participate in the initial debugging experiment after the product assembly.
In the debugging experiment, it is more important to require the inspection technician to adjust the displacement value and displacement direction of the rotor position in the assembly process according to the actual offset data of the motor center line and electromagnetic center actually tested in the no-load and load experiment in the prototype trial assembly experiment.
Post time: Jul-04-2024
