Hi,
We have repaired motor part of BRP (boiler water recirculation pump) under the direction of maker's technical assistant. After we disassembled the rotor, we found the rotor shaft condition was heavily changed as attached photo. TA said the black color is magnetites stuck on the shaft. TA said that the magnetites are being used to prevent crystallization of the mineral ions. Then, TA commended us to clean out the stuck magnetites with sand papers.
However, I wonder if it's not because of stuck magnetites but it's because the surface of the shaft has been distorted by electromagnetic field (maybe, it's magnetized. as TA is a Japanese, he might have confused.).
Can anyone provide me with a precise explanation about this shaft surface changes?
We have repaired motor part of BRP (boiler water recirculation pump) under the direction of maker's technical assistant. After we disassembled the rotor, we found the rotor shaft condition was heavily changed as attached photo. TA said the black color is magnetites stuck on the shaft. TA said that the magnetites are being used to prevent crystallization of the mineral ions. Then, TA commended us to clean out the stuck magnetites with sand papers.
However, I wonder if it's not because of stuck magnetites but it's because the surface of the shaft has been distorted by electromagnetic field (maybe, it's magnetized. as TA is a Japanese, he might have confused.).
Can anyone provide me with a precise explanation about this shaft surface changes?