There are many reasons that can cause vibration in the construction of the unit and ship pump room, and some factors are related and interactive. In summary, there are four main reasons.

The electric motor is the main equipment of the unit, and the magnetic imbalance inside the motor and the imbalance of other electrical systems often cause vibration and noise. For example, in the operation of asynchronous motors, the fixed rotor inter diameter alternating magnetic pulling force generated by the interaction of fixed rotor tooth harmonic magnetic flux, or in the operation of large synchronous motors, the fixed rotor magnetic center does not diverge, or the clearance in all directions exceeds the allowable deviation value, which may cause periodic vibration and noise of the motor.

The rotating components of motors and pumps in the mechanical field have uneven quality, rough manufacturing, poor device quality, asymmetric unit axis, swing exceeding the allowable value, poor mechanical strength and rigidity of components, wear and damage of bearings and sealing components, critical rotational speed of pumps, and resonance of fixed frequency of units, etc

In terms of hydraulics, uneven inlet flow rate and pressure distribution of pumps, pressure pulsation, liquid flow around, deviation and detachment, non rated conditions, and steam erosion caused by various reasons are common causes of pump unit vibration. The sudden changes in pressure and hammer action in the water pipeline caused by dynamic transition processes such as pump start and stop, valve opening and closing, situation changes, and emergency stop accidents often result in vibration in the pump room and units.

In terms of hydraulic engineering and other aspects, the design of the unit's inlet flow channel is unreasonable, it does not cooperate with the unit, the depth of pump engulfment is unreasonable, the number of unit starts and stops is unreasonable, etc., the inlet conditions deteriorate, vortex is generated, cavitation is induced, and the vibration of the unit and pump room is aggravated. When starting with a unit that breaks the siphon vacuum cutoff, it is difficult to clamp the air in the hump section, resulting in an unreasonable design of the flap door for the unit that breaks the siphon time for too long. The flap door of the unit that closes when opened and supports the pump and motor that occasionally collide with the flap door seat will also cause uneven vibration of the unit due to poor foundation rigidity and other reasons.