【Q&A】July 25, 2017

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.

1. Bearing damage (caused by lack of oil or other reasons). 2. The foundation screws are loose or the foundation is damaged, and the fixing devices for the inlet and outlet pipes are loose. 3. The motor operates with a missing phase. 4. Air is drawn into the pump or the inlet valve is not fully open. 5. Other mechanical failures of the pump

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.

1. Cavitation occurs. During cavitation, bubbles are formed and then burst, which causes vibration and noise. If the vibration is caused by pump cavitation, it is necessary to consider changing the installation height or increasing the system pressure; in some cases, it may even be required to select or design a different pump. 2. The rotor balance deteriorates. When the rotor is unbalanced, its center of gravity and center of rotation are displaced significantly, which generates unbalanced forces during rotation; these vibrations become more pronounced, especially at higher speeds. On the one hand, it may be that during manufacturing or assembly, the rotor balance does not meet the design requirements ； On the other hand, after the pump has been operating for a certain period of time, certain factors such as shaft deformation due to stress or excessive wear of components may cause a decrease in the rotor’s balance accuracy. In both cases, it is necessary to conduct a rebalancing test on the rotor. 3. Blockage in the impeller flow channel. When foreign objects block the impeller’s flow channels, causing the impeller to become unbalanced and subjected to uneven forces, it is necessary to remove the impeller for thorough cleaning. 4. Bearing issues. If the bearing is damaged, in addition to an increase in its own operating noise, it will disrupt the stability of the rotor’s movement, resulting in increased vibration and noise in the pump unit. Additionally, excessive radial play in the bearings can also cause abnormal noise. The bearing needs to be replaced at this time. 5. Reasons for installation. Issues such as looseness between the centrifugal pump and its base, or between the base and the foundation, as well as an insufficient degree of coaxiality in the coupling that connects the motor to the pump, can all cause vibration and noise. In such cases, it is necessary to retighten the connection bolts or realign them properly.

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.

1) The pump shaft and the motor shaft are not aligned. 2) The flow rate exceeds the specified range. 3) Cavitation occurs. 4) Unbalanced rotating parts. 5) The foot screws are loose.