Research On On-line Monitoring And Fault Diagnosis Method Of Motor And Centrifugal Pump Set

In the petrochemical industry,the machine pump device occupies a very important position in the entire system,which can be said to be the "heart of the device." The pump equipment provides power for the medium transportation,and the transported medium is often characterized by high temperature and high pressure,corrosion,toxicity,flammability and explosion Once the pump equipment has problems during operation,it will cause a series of serious consequences.It may cause economic losses,environmental pollution,and may cause catastrophic consequences such as personal injury or death.Therefore,it is necessary to implement online monitoring and fault diagnosis for the motor and centrifugal pump.This paper mainly studies the rotor broken bar fault of the motor,the flow state of the fluid in the three-way filter at the inlet of the centrifugal pump is simulated and analyzed,analyzes the cause of excessive vibration of the centrifugal pump in a power plant,and gives suggestions for treatment.(1)Aiming at the motor rotor breaken bar fault,an experimental platform was built to simulate the motor rotor breaken bar fault.The stator current signal and vibration signal of normal motor and broken bar motor were obtained under no-load state and full-load state respectively.After analyzing and processing the collected signals,it is known that when the motor is running under no-load conditions,the external factors have less influence on the motor.Compared with the current signal,the vibration signal can more clearly identify the characteristic frequency of the motor rotor breaken bar fault.When the motor is running under full load,because the motor is affected by the load,voltage,noise signal,etc.,the frequency component of the vibration signal of the faulty motor becomes very complicated,the fault characteristic frequency is difficult to be distinguished,a and it is easy to cause misjudgment to the fault identification of the motor.But the current signal can clearly identify the broken bar of the motor,and the characteristic frequency of the fault is obvious.(2)The three-pass filter was solid modeled,and then the model was imported into ANSYS Fluent for processing to extract the fluid domain.After meshing the extracted fluid domain in Mesh and setting the boundary conditions,the velocity field and pressure field of the fluid passing through the filter were analyzed at different flow rates.It can be seen that when the medium enters the filter through the pipeline,the fluid generates a vortex at the filter screen.At the right-angle bend of the filter,the flow direction of the fluid changes abruptly,due to the sudden decrease of the flow area of the filter at the right-angle bend,the flow velocity of the fluid passing there suddenly increases,and the flow direction is seriously disturbed.An unstable flow has formed here.Under the three flow rates,the pressure gradient of the cross section has the same trend,the pressure at the inlet of the filter is the largest,and the pressure near the filter screen is the smallest.The inlet flow rate is different,the pressure difference between the inside and outside of the filter is also different.The larger the velocity is,the greater the difference of pressure is.(3)The reasons for the excessive vibration of the power plant’s desulfurization pump during operation were analyzed.The analysis pointed out that the main reason for the vibration of the pump body was caused by the fluid-induced vibration,and the corresponding solutions were given.