Pump apparatus, test operation method of pump apparatus, motor assembly and method for identifying abnormal vibration of motor assembly

A motor assembly comprising:

• a motor;
• an inverter as a speed changing means for the motor, and
• a controller for controlling the motor, wherein the motor assembly has a first bearing disposed on a counter-load side of the motor and which rotatably supports a drive shaft of the motor, and a second bearing disposed on a load side of the motor and which rotatably supports the drive shaft, and the motor assembly comprises a first motor-side vibration sensor for detecting a vibration of the first bearing, a second motor-side vibration sensor for detecting a vibration of the second bearing, and an inverter-side vibration sensor for detecting a vibration of the inverter, and wherein the controller detects an abnormal vibration based on values detected by the first motor-side vibration sensor, the second motor-side vibration sensor and the inverter-side vibration sensor,
• wherein the controller calculates vibration levels of values, detected by the first motor-side vibration sensor, the second motor-side vibration sensor and the inverter-side vibration sensor, for each of varying frequency ranges, and stores the calculated vibration levels as measured vibration values in a storage unit, wherein the controller has at least one predetermined threshold value to be compared with at least one of the vibration levels, and wherein when a state in which the at least one vibration levels of the measured vibration values is not more than the threshold values is termed a first state, and a state in which the at least one vibration levels of the measured vibration values is more than the threshold values is termed a second state, the controller detects the abnormal vibration when at least one of the vibration levels is in the second state, and identifies a cause of the abnormal vibration based on the measured vibration values, wherein it is determined that an abnormality has occurred in the drive shaft when the inverter-side vibration sensor is in the first state, the first motor-side vibration sensor is in the second state, and the second motor-side vibration sensor is in the second state and, in addition, a first abnormal vibration detected by the first motor-side vibration sensor and a second abnormal vibration detected by the second motor-side vibration sensor belong to a same frequency range.