Analysis of vibration causes

Analysis of vibration causes

Analysis of the causes of water pump vibration There are many reasons for the vibration of the unit and pump house building, and some factors are both related and interactive. In summary, there are mainly four reasons.

Electrical aspects

Submersible pump

Submersible pump

The motor is the main equipment of the unit, and the internal magnetic imbalance of the motor and the imbalance of other electrical systems often cause vibration and noise. If the radial alternating magnetic pull between the stator and rotor is generated by the interaction of harmonic magnetic flux between the stator and rotor teeth during the operation of an asynchronous motor, or if the magnetic center of the stator and rotor is inconsistent or the air gap difference in each direction exceeds the allowable deviation value during the operation of a large synchronous motor, it may cause periodic vibration and noise of the motor.

Mechanical aspect

Unbalanced quality, rough manufacturing, poor installation quality, asymmetric axis of the unit, swing exceeding allowable values, poor mechanical strength and stiffness of components, wear and tear of bearings and sealing components, as well as resonance caused by the critical speed of the water pump and the inherent frequency of the unit, can all generate strong vibration and noise.

Hydraulic aspect

Water pump control valve

Water pump control valve

Uneven flow velocity and pressure distribution at the inlet of the water pump, pressure pulsation of the working liquid at the inlet and outlet of the pump, liquid flow, deviation and detachment, non rated operating conditions, and pump cavitation caused by various reasons are common causes of pump unit vibration. The rapid pressure changes and water hammer effects in the water supply pipeline caused by dynamic transition processes such as water pump startup and shutdown, valve opening and closing, working condition changes, and emergency shutdown accidents often lead to vibration in the pump room and unit.

Hydraulic and other aspects

Unreasonable design of the unit inlet channel or mismatch with the unit, improper submergence depth of the water pump, and unreasonable starting and stopping sequence of the unit can worsen the inlet conditions, generate vortices, induce cavitation or worsen the vibration of the unit and pump room. When using units that break the siphon vacuum and cut off the flow, if the air entrainment in the hump section is difficult, the siphon time will be too long; The design of the flap door of the unit with the flap door cut off is unreasonable, opening and closing at times, constantly hitting the flap door seat; Uneven settlement or poor rigidity of the foundation supporting the water pump and motor can also cause vibration of the unit.

Source of the article: excerpts from Baidu Baike