Motor design rules (two)
7. Asynchronous motor has large air gap, large magnetic resistance and large number of excitation ampere, which makes the motor excitation current increase and the motor power factor decrease. However, the air gap is large, the harmonic magnetic field is weakened, the additional loss of the motor is reduced, and the air gap is too small. Fixed rotor broom and reduced motor efficiency due to increased additional losses.
8. Asynchronous motor rotor skew can weaken the rotor bar along the axial harmonic potential phase, thereby reducing the additional synchronous torque and additional asynchronous torque, reducing the additional loss of the motor, improving efficiency and reducing noise. vibration.
9. Single-layer windings should not be used for motors with large capacity. Motors with smaller capacity should not be double-layered.
10. Large motors should not be made of aluminum alloy because of the rigidity and the strength.
11, as far as possible on the shaft to avoid the use of different width of the keyway (ie, meson groove) the core should be rounded.
12. When the rolling bearing is used at both ends of the motor, the axial direction should not be stuck. Because the heat dissipation of the rotating shaft is worse than that of the stator bracket when the motor is running, the temperature rises, the thermal expansion of the rotating shaft is greater than that of the stator component, and the bracket, the base. Can not freely expand, so generally add a wave meson plus beer cover.
13. The length of the shaft and the rotor chip should not be too long. (The middle part of the shaft core can be reduced.)
14. The structure with rolling bearing should not cause the motor rotor to produce axial turbulence. (So the beer is equipped with a wave meson.) The sliding bearing at the front end of the rotor is curved. The front of the portable vacuum cleaner is not bent. The front end is the E meson structure. Bit control is very small 0.1~0.4mm
15. The motor is fixed, the rotor core should not be misplaced, and the misalignment is unfavorable. a: The misalignment is equivalent to the reduction of the effective area of the air gap, the excitation current is increased, and the power factor is reduced. The stator current is large and the stator has large copper loss and low efficiency. The temperature rises. B: The rotor is subjected to an axial force to accelerate the bearing wear. It increases the noise and vibration of the motor. (But some finished products run to the front end in one direction, often grinding one end of the bearing at this time intentionally misplaced) c: affecting the normal ventilation of the motor.
16. Pay attention to the quality of the rotor aluminum of the asynchronous motor (see the sulphate solution chip)
