Fault analysis of pump vibration

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During the operation of a water pump, vibration problems may occur. What exactly causes such problems? As a leader in stainless steel pumps, Youfu offers you the following insights based on its many years of experience in production, manufacturing, and maintenance. There are many reasons that cause vibration in the turbine hall and pump house structures, and some of these factors are interconnected and interact with each other. Generally speaking, there are mainly the following four categories of causes. I. Electrical aspects: The motor is the main component of the unit; imbalances in the magnetic field within the motor and malfunctions in other electrical systems often cause vibration and noise. For example, in an asynchronous motor during operation, the radial alternating magnetic pulling force between the stator and rotor generated by the interaction of the harmonic fluxes at the stator and rotor teeth, or in a large synchronous motor during operation, situations such as misalignment of the magnetic centers of the stator and rotor or air-gap differences in various directions exceeding the allowable limits, can all cause periodic vibration of the motor and the generation of noise. II. Mechanically, issues such as uneven mass in the rotating parts of motors and pumps, shoddy manufacturing quality, poor installation standards, asymmetry in the axis of the unit, deflection exceeding allowable limits, low mechanical strength and stiffness of components, wear and damage to bearings and sealing elements, as well as resonance caused by the critical speed of the pump coinciding with the natural frequency of the unit, can all lead to severe vibration and noise. III. In terms of hydraulics, uneven flow velocity and pressure distribution at the pump inlet, pressure fluctuations of the fluid flowing in and out of the pump, fluid bypassing around the pump, deviation in flow direction, and fluid separation from the pump surface, as well as operation under conditions other than those specified, and pump cavitation caused by various factors, are all common causes of vibration in pump units. Dynamic transition processes such as the start-up and shutdown of water pumps, the opening and closing of valves, changes in operating conditions, and emergency shutdowns in case of accidents, which cause sudden pressure changes in the water conveyance pipes and water hammer effects, often also lead to vibrations in the pump house and the pumping units. IV. Hydraulic aspects and other factors: An unreasonable design of the water inlet channel for the unit, or a design that is not compatible with the unit; an inappropriate submersion depth of the pump; as well as an unreasonable sequence for starting and stopping the unit – all these can deteriorate the water inlet conditions, cause vortices, lead to cavitation, or increase the vibration of the unit and the pump house. In units that use vacuum interruption by breaking the siphon effect, during startup, if it is difficult for air to be entrained in the hump section, the siphon formation time becomes excessively long ； The gate design of the units with gate-driven flow shutdown is unreasonable; it opens and closes repeatedly, constantly striking the gate seat ； Reasons such as uneven settlement of the foundation supporting the water pump and motor, or poor rigidity of the foundation, can also cause vibration in the unit. Youfu Pump Industry.