The rotor shield sleeve has wear marks
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After the in-shaft circulation shielded pump was operated for a few minutes before being stopped, the cast-aluminum rotor showed discontinuous wear marks on one side of its rotor shielding sleeve; these marks disappeared after enlarging the diameter of the bolt holes in the shaft head. What could be the cause?
Has the cast aluminum rotor shifted axially on the shaft?
Tape was wrapped around the outside for marking, but scratches still remain; it’s likely not caused by something inside the rotor. Almost all units of the same batch and model exhibit this symptom. The scratches disappeared after changing the internal circulation flow rate. Since the scratches are discontinuous and their number corresponds exactly to the area related to the cast aluminum section, could the influence of the flow field be ruled out?
Consider that there may not be enough circulation of the cooling medium flowing through it
It can’t be that there were some particles inside before; after grinding them and they broke apart, it’s gone
The pattern of these traces is fairly regular; the medium used in the experiments is also water. As long as the circulation holes do not expand, this pattern will appear in almost all cases
According to you, then it’s caused by axial force
This is the test pattern after reduction of the cycle; the black areas represent markers, and the number of traces is exactly equal to that of the punching slots
The other one has marks only on the side of the rear cover; there are no marks near the pump body end
The appearance quality of this rotor is very poor. The phenomenon you mentioned seems to indicate an issue with the structural design – for example, you said that when the air gap increases, the friction marks on the rotor disappear; it’s hard to say whether there is any connection between these two things. Without structural design or internal heat/circulation balance design, it’s hard to give general statements – there are too many uncertainties involved!