1. The pump itself caused by mechanical failure:
Impeller and pump shaft fastening nut loose or pump shaft deformation and bending, resulting in multi impeller, direct friction with the pump body, or bearing damage, it is possible to reduce the pump speed.
2. Caused by the motor:
Motor due to the winding burn, and loss of magnetism, maintenance of the winding turns, wire diameter, wiring method changes, or the failure of the maintenance of the fault is not completely eliminated factors will make the pump speed change.
3. Human factors:
Damage to the part of the user because of original motor, free with the other a motor driven resulting in a small flow and low lift even of Sheung Shui consequences.
