Rotating shaft is a very key structural part of motor products, is the direct body of mechanical energy transfer, at the same time, for most motor products, rotating shaft will also be an important part of the magnetic circuit of the motor, bearing a certain magnetic shard effect. The vast majority of the motor shaft material for the magnetic function of the steel, especially for large high-speed motor and small and medium-sized induction motor, motor rotor core directly with the shaft, no-load state, motor rotor induction frequency is very low, yoke magnetic flux will penetrate deep into the rotor, different motors, different states of the shaft to bear the magnetic circuit shard effect is not the same.
In the magnetic circuit calculation of the motor, the rotating shaft part of the motor is often included in the magnetic circuit, and some basic principles are determined according to different poles and rotating shaft materials. The rotating shaft of the 2-pole motor has a large magnetic shunt effect, which is mainly due to the matching relationship between the rotor and the shaft of the 2-pole motor, and the particularity of the relatively small outside diameter of the rotor of the motor. The rotor side of the motor 1/6, that is, 1/3 of the diameter, is included in the magnetic circuit calculation, that is, the magnetic circuit calculation of the motor will take this part of the rotating shaft as the participating object; For motors with 4 poles and above, 1/12 of the single side of the shaft, that is, 1/6 of the diameter, is included in the magnetic circuit calculation. In view of the principle of the degree of participation of the magnetic circuit calculation on the shaft under different pole conditions, the material change of the 2-pole motor has a greater impact on the performance of the motor. For example, after directly replacing the ordinary shaft of the 2-pole motor with a stainless steel shaft, there will be serious current increase and winding heating problems due to the magnetic density saturation problem. For other multi-pole motors, due to the relationship between the diameter of the motor shaft and the diameter and size of the rotor punch, and the principle of the magnetic circuit design of the motor, the ordinary shaft is replaced with a stainless steel shaft, and the performance of the motor is not very important.
Post time: Mar-11-2025