① The pump is mainly caused by factors such as large bearing clearance, poor concentricity between rotor and shell or excessive friction between rotor and stator.
② Motor, the reasons include large bearing clearance, unbalanced rotor or uneven air gap with stator.
③ Installation and operation, if the process operation parameters deviate too much from the rated parameters, it will easily lead to the imbalance of pump operation stability, such as the vibration caused by unstable flow control of outlet valve, which requires the equipment installation process to run as close as possible to the rated parameters.