JPH09297614A - Torque abnormality monitoring method for motor and abnormality processing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the proper abnormality processing by deciding the torque abnormality when the torque of a motor exceeds its threshold previously decided based on the torque value that is measured in a normal mode and in every operation control process of the motor. SOLUTION: The moving up-don positions of a suction pipe 3 are continuously measured based on the measurement signal of a revolution detector 9 and the effective diameter of a sprocket wheel 8. Then the start/stop operations and a revolution speed control command of a motor 10 are outputted to a speed controller 11 based on the moving up-down position information on the pipe 3 and a sequence control program. The torque value of the motor 10 which are continuously measured by a torque measurement device 12 are compared with the threshold of every process that is previously decided based on the torque value measured in a normal mode of the motor 10. Then the torque abnormality is decided when the measured torque value exceeds its threshold, and an abnormality alarm is outputted. Thus, the proper abnormality processing can be carried out for the torque of the motor 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque abnormality monitoring method for an electric motor in a sequence-controlled automated plant in which each step of operation control of the electric motor is sequentially advanced according to a predetermined control sequence, and an abnormality processing method therefor.

[0002]

2. Description of the Related Art In an automation plant equipped with a sequence control in which each step of operation control of an electric motor is sequentially advanced according to a predetermined control sequence, as a method for monitoring a torque abnormality of the electric motor, each step of the operation control of the electric motor is performed. Regardless of the above, it is common to take a coping method of stopping the electric motor as an abnormality when the torque exceeds a certain threshold value which is predetermined in consideration of the rated capacity.
In this method, a monitoring means for tripping the non-fuse breaker against an overcurrent of the electric motor is used as a general method.

[0003]

However, irrespective of each step of the operation control of the electric motor as described above, when the torque exceeds a certain threshold value determined in consideration of the rated capacity, the electric motor is judged to be abnormal. The method of stopping
When the electric motor torque changes due to deterioration of the plant over time, or when the torque during normal operation differs depending on each step of operation control of the electric motor, it is not possible to accurately detect the abnormality. In addition, even if the same process is not performed again when an abnormality occurs, such a treatment cannot be automatically performed, which impedes automation.

Incidentally, for example, in Japanese Unexamined Patent Publication No. 7-40021, the load currents of the driving motors of all the pinch rolls of the continuous casting equipment are continuously monitored and the pattern of the current change is analyzed to determine the pattern of all the pinch rolls. A technology for detecting abnormalities such as bearing wear, roll wear, roll eccentricity, and rolling reduction is disclosed.However, this method can cope with changes in motor torque due to aging of the plant, but The problem similar to the above occurs when the torque in the normal state is different depending on each control process.

It is an object of the present invention to provide a torque abnormality monitoring method for an electric motor and an abnormality processing method therefor, which have been made to solve the above-mentioned problems of the prior art.

[0006]

According to the present invention, there is provided a method for monitoring an abnormal torque of a motor in a sequence-controlled automated plant, in which each step of the operation control of the motor is sequentially advanced according to a predetermined control sequence. The torque is continuously measured in each step, and when the torque exceeds a predetermined threshold value based on the torque measurement value at the normal time in each step of the operation control of the electric motor, the torque is abnormal. A method for monitoring a torque abnormality of an electric motor, characterized by making a determination.

The threshold value can be changed in a predetermined cycle by sampling a past measured value of the torque of the electric motor determined to be normal. Further, the present invention, in the torque abnormality processing method of the motor when it is determined to be abnormal by the torque abnormality monitoring method of the electric motor, is predetermined according to each step of the operation control of the electric motor which has been made the torque abnormality. The torque abnormality processing method for an electric motor is characterized by eliminating the torque abnormality based on the processing procedure.

[0008]

FIG. 1 is a schematic diagram showing the overall configuration of an automatic suction removal apparatus for accumulated particulate matter in a vertical cylindrical container as an example of an automated plant suitable for carrying out the method of the present invention. is there. In this figure, reference numeral 1 is a vertical cylindrical container in which a granular material 2 is deposited. Reference numeral 3 denotes a suction pipe having its tip inserted into the vertical cylindrical container 1 and having its upper end connected to a vacuum suction device (not shown) for sucking the powdery granular material 2. Reference numeral 4 is a gripping device that grips the suction tube 3 and moves up and down, and 5 is a guide that guides the gripping device 4 up and down.

Reference numeral 6 is a chain whose one end is connected to the gripping device 4 and the other end is connected to the balance weight 7. 8 is a sprocket wheel that engages with the chain 6 to rotate, 9 is a rotation detector connected to the rotation shaft of the sprocket wheel 8, and 10 is a rotation of the sprocket wheel 8 that raises and lowers the suction pipe 3 via the gripping device 4. The speed of the electric motor is controlled by the speed control device 11. A torque measuring device 12 is connected to the rotating shaft 10a of the electric motor 10 to measure the load torque.

Reference numeral 13 is a control device which inputs the measurement signals of the rotation detector 9 and the torque measuring device 12 and has the following functions. (1) Measurement signal of rotation detector 9 and sprocket wheel 8
The vertical position of the suction tube 3 is continuously measured from the effective diameter of (2) The sequence control program for the electric motor 10 is built in, and the start / stop of the electric motor 10 and the rotation speed control command are output to the speed control device 11 according to the elevation position information of the suction tube 3 and the sequence control program. (3) Measured torque in each step of the operation control of the electric motor 10 continuously measured by the torque measuring device 12 and each predetermined step based on the torque measurement value at the normal time in each step of the operation control of the electric motor 10. When the measured torque exceeds the threshold value, it is determined to be abnormal and an abnormality alarm is output. (4) Corresponding to each step of the operation control of the electric motor in which the torque abnormality has occurred, the action command according to the abnormality processing program stored in advance and stored is output.

Below, the lowering control in the process of raising and lowering the suction tube 3 in the above-mentioned automatic suction removing device will be specifically explained. First, the descending control of the suction pipe 3 is divided into the following three steps. (i) A high-speed descending step of descending from the upper end position of the suction pipe 3 to a position where the lower end of the suction pipe is higher than the upper end of the vertical cylindrical container 1 by a predetermined height at high speed. (ii) From the position where the lower end of the suction pipe is higher than the upper end of the vertical cylindrical container 1 by a predetermined height, the lower portion of the suction pipe is inserted into the vertical cylindrical container 1, and the lower end of the suction pipe is located at the upper end of the powdery granular material 2. Medium-speed descending process of descending to an approaching position at medium speed. (iii) A low speed descending step in which the lower end of the suction pipe is sucked from the position where the lower end of the suction pipe is close to the upper end of the powdery granular material 2 and is slowly moved down to the bottom of the vertical cylindrical container 1.

Therefore, if torque is measured during normal operation in the descending process of the suction pipe 3 and a torque waveform as shown by the solid line P _S in FIG. 2 is obtained, for example, the torque waveform is followed by high-speed descending. The torque threshold values for the medium speed descent and the low speed descent process are set as indicated by the broken line S and stored in the control device 13. Here, it occurs when the suction tube 3 is controlled to descend,
The following cases are assumed as the abnormal phenomenon of the torque of the electric motor 10 in each process. (a) When descending at high speed; the lower end of the suction pipe 3 descends at a high speed to the upper end position of the vertical cylindrical container 1 due to an error in measuring the vertical position of the suction pipe 3, and the mutual eccentricity between the suction pipe 3 and the vertical cylindrical container 1 As a result, the lower end of the suction pipe 3 collides with the upper end of the vertical cylindrical container 1 when descending at a high speed, resulting in torque P as shown in FIG. 3 (a), for example.
Rises. (b) When descending at medium speed; due to the mutual eccentricity of the suction pipe 3 and the vertical cylindrical container 1, the lower end of the suction pipe 3 collides with the upper end of the vertical cylindrical container 1 when descending at medium speed, for example, as shown in FIG. 3 (b). As shown, the torque P increases. (c) When descending at a low speed; the powdery granular material 2 sucked into the lower end of the suction pipe 3 is clogged and clogged, and the suction is not performed normally, so the lower end of the suction pipe 3 collides with the upper end of the accumulated powdery granular material 2. Then, the torque P increases as shown in FIG. 3 (c), for example.

Therefore, when the torque abnormality as shown in the above (a) to (c) occurs, it is necessary to take the following measures according to each situation. (B) In the case of abnormalities such as the above (a) and (b), the suction pipe 3 is stopped for a while, and the lower end of the suction pipe 3 enters the upper end of the vertical cylindrical container 1 in the radial direction. While lowering the eccentricity by applying force, the descending of the suction pipe 3 is restarted. (B) In the case of an abnormality such as the above (c), if the suction tube 3 is automatically raised, the clogging at the tip will be cleared. Therefore, after raising the suction tube 3, it is slowly lowered again. To suck.

It should be noted that although the torque itself fluctuates when the equipment and the like deteriorates with time, in order to cope with the fluctuation of the torque, the past measured value of the torque of the motor judged to be normal is sampled and the threshold value is sampled. May be changed at a predetermined cycle as shown by a chain double-dashed line S ^* in FIG. 4, and the automation thereof is also possible. Further, the above-mentioned example is one in which the present invention is applied to an automatic suction / removal device for accumulated particulate matter in a vertical cylindrical container, but the present invention is not limited to this, and for example, for an elevator motor for an elevator. Abnormality monitoring, etc.
It goes without saying that the present invention can be applied without departing from the scope of the constitution of the present invention.

[0015]

As described above, according to the present invention,
Automatic torque control of a motor in a sequence control automation plant in which each step of motor operation control is sequentially advanced according to a predetermined control sequence.It is possible to perform appropriate abnormality processing for each step. By doing so, the automation rate of the equipment can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an automated plant suitable for application of the present invention.

FIG. 2 is a characteristic diagram showing an example of setting a torque threshold value.

3 (a) to 3 (c) are characteristic diagrams showing an example of an abnormal torque waveform in each descending step of the suction pipe.

FIG. 4 is a characteristic diagram showing another example of setting a torque threshold value.

[Explanation of symbols]

 1 Vertical cylindrical container 2 Powder and granular material (deposit) 3 Suction tube 4 Grasping device 5 Guide 6 Chain 7 Balance weight 8 Sprocket wheel 9 Rotation detector 10 Electric motor 11 Speed control device 12 Torque measuring device 13 Control device

Claims (3)

[Claims] 1. A method for monitoring abnormal torque of a motor in a sequence control automation plant in which each step of the operation control of the motor is sequentially advanced according to a predetermined control sequence, wherein torque in each step of the operation control of the motor is continuously measured. And a torque abnormality is determined when the torque exceeds a predetermined threshold value based on the torque measurement value at the normal time in each step of the operation control of the motor. Torque abnormality monitoring method. 2. The method for monitoring a torque abnormality of an electric motor according to claim 1, wherein the threshold value is changed in a predetermined cycle by sampling an actual measured value of past torque of the electric motor determined to be normal. 3. A torque abnormality processing method for a motor when it is determined to be abnormal by the torque abnormality monitoring method for an electric motor according to claim 1 or 2, wherein each of the operation control of the motor determined to be the torque abnormality is performed. A torque abnormality processing method for an electric motor, which eliminates the torque abnormality based on a processing procedure that is predetermined according to each of the steps.