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

Abstract

There is disclosed a pump apparatus which can more accurately determine the occurrence of an abnormal vibration. The pump apparatus includes: a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling the pump. The controller includes a storage unit for storing a measured vibration value measured by the vibration detector. The storage unit has a storage table which, when the rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores the measured vibration value measured at each step.

1 . A pump apparatus comprising:
 a pump;   an electric motor for driving the pump;   an inverter as a speed changing means for the electric motor;   a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and   a controller for controlling the pump, wherein the controller comprises a storage unit for storing a measured vibration value measured by the vibration detector, the storage unit having a storage table which, when a rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores a measured vibration value measured at each step,   wherein the controller comprises a test operation mode for increasing the rotational speed of the pump stepwise to the predetermined rotational speed, and storing the measured vibration value measured at each step,   wherein in the test operation mode, the controller increases the rotational speed of the pump stepwise to the predetermined rotational speed while keeping a valve on a discharge side of the pump open so that the pump is operated at a maximum efficiency point.   
     
     
         2 . A test operation method of a pump apparatus including a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling a rotational speed of the pump, and including a storage unit for storing a measured vibration value measured by the vibration detector, said method comprising increasing the rotational speed of the pump stepwise to a predetermined rotational speed while performing a shut-off operation of the pump with a valve on the discharge side of the pump fully closed, and storing the measured vibration value measured at each step in a storage table of the storage unit. 
     
     
         3 . A test operation method of a pump apparatus including a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling a rotational speed of the pump, and including a storage unit for storing a measured vibration value measured by the vibration detector, said method comprising: opening a valve on a discharge side of the pump so that the pump is operated at a maximum efficiency point; and increasing the rotational speed of the pump stepwise to a predetermined rotational speed, and storing the measured vibration value measured at each step in a storage table of the storage unit. 
     
     
         4 . 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 level(s) of the measured vibration values is not more than the threshold value(s) is termed a first state, and a state in which the at least one vibration level(s) of the measured vibration values is more than the threshold value(s) 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.   
     
     
         5 . The motor assembly according to  claim 4 , wherein the controller continues an operation of the motor while issuing an alarm when the inverter-side vibration sensor is in the second state, the first motor-side vibration sensor is in the first state, and the second motor-side vibration sensor is in the first state. 
     
     
         6 . The motor assembly according to  claim 4 , wherein the threshold value comprises a first threshold value and a second threshold value which is higher than the first threshold value, and wherein the controller stops an operation of the motor when at least one of the measured vibration values of the first motor-side vibration sensor, the second motor-side vibration sensor and the inverter-side vibration sensor is more than the second threshold value. 
     
     
         7 . The motor assembly according to  claim 4 , wherein the motor assembly comprises a motor casing which houses the motor and which has a first bearing support that supports the first bearing, and a second bearing support that supports the second bearing; and an inverter housing which houses the inverter, and wherein the first motor second motor-side vibration sensor is mounted to the first bearing support, the inverter-side vibration sensor is mounted to the second bearing support, and the inverter-side vibration sensor is mounted to the inverter or an internal surface of the inverter housing. 
     
     
         8 . The motor assembly according to  claim 7 , wherein the drive shaft penetrates a through-hole of the inverter. 
     
     
         9 . The motor assembly according to  claim 4 , wherein the controller performs a vibration-reducing operation, which involves change of a rotational speed of the motor, upon the detection of the abnormal vibration. 
     
     
         10 . A pump apparatus comprising a pump driven by the motor assembly according to  claim 4 . 
     
     
         11 . A method for identifying an abnormal vibration of a motor assembly including a motor, and an inverter as a speed changing means for the motor, said method comprising identifying an abnormal vibration based on values detected by a first motor-side vibration sensor for detecting a vibration of a first bearing which rotatably supports a drive shaft of the motor, a second motor-side vibration sensor for detecting a vibration of a second bearing disposed on the opposite side of the motor from the first bearing and which rotatably supports the drive shaft, and an inverter-side vibration sensor for detecting a vibration of the inverter. 
     
     
         12 . The method according to  claim 11 , wherein the vibration levels of the values, detected by the first motor-side vibration sensor, the second motor-side vibration sensor and the inverter-side vibration sensor, are calculated as measured vibration values for each of varying frequency ranges, and wherein when a state in which the vibration level(s) of the measured vibration value(s) is not more than at least one predetermined threshold value, which is to be compared with at least one of the vibration levels, is termed a first state, and a state in which the vibration level(s) of the measured vibration value(s) is more than the threshold value(s) is termed a second state, an abnormal vibration is detected when at least one of the vibration levels is in the second state, and the cause of the abnormal vibration is identified based on the measured vibration values. 
     
     
         13 . 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 comprises at least one vibration detector for detecting a vibration of the motor assembly, and wherein the controller performs a vibration-reducing operation, which involves a change of a rotational speed of the motor, based on values of the at least one vibration detector.   
     
     
         14 . The motor assembly according to  claim 13 , wherein the controller calculates a vibration level of a value, detected by the vibration detector, for each of varying frequency ranges and, when a state in which the vibration level is not more than a predetermined first threshold value is termed a first state, and a state in which the vibration level is more than the first threshold value is termed a second state, the controller performs the vibration-reducing operation when at least one of the vibration levels is in the second state. 
     
     
         15 . The motor assembly according to  claim 14 , wherein the controller has a second threshold value which is higher than the first threshold value, and wherein when a state in which the vibration levels are not less than the second threshold value is termed a third state, the controller stops the motor when at least one of the vibration levels is in the third state. 
     
     
         16 . The motor assembly according to  claim 13 , wherein the motor assembly comprises a motor section including the motor, and an inverter section including the inverter. 
     
     
         17 . The motor assembly according to  claim 13 , wherein the motor assembly comprises, as the vibration detector, at least one of a first motor-side vibration sensor for detecting a vibration of an inverter-side first bearing, a second motor-side vibration sensor for detecting a vibration of a second bearing disposed on the opposite side of the motor from the first bearing, and an inverter-side vibration sensor for detecting a vibration of the inverter. 
     
     
         18 . A pump apparatus comprising a pump driven by the motor assembly according to  claim 13 . 
     
     
         19 . The pump apparatus according to  claim 18 , wherein the pump apparatus comprises as the vibration detector a pump-side vibration sensor for detecting a vibration of the pump.