Lifting electromagnet abnormality diagnosis device and lifting electromagnet device including the same

Abstract

To provide a lifting electromagnet abnormality diagnostic device capable of efficiently detecting abnormality of resistance of a coil in lifting work by a lifting electromagnet.SOLUTION: The lifting electromagnet abnormality diagnosis device 10 includes a measurement value acquisition unit 11 configured to acquire a measurement value of a current flowing through the exciting coil 91 of the lifting electromagnet 90, and a start-time abnormality diagnosis unit 12 configured to diagnose an abnormality of the exciting coil 91 based on a gradient of a change in the measurement value of the current acquired by the measurement value acquisition unit 11 when energization of the exciting coil 91 of the lifting electromagnet 90 is started to positively excite the exciting coil 91.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lifting electromagnet abnormality diagnosis device that diagnoses a lifting electromagnet that lifts steel materials by electromagnetic force generated by current flowing through an exciting coil, and a lifting electromagnet device equipped with the same. [Background technology]

[0002] A lifting electromagnet device is known that includes a lifting electromagnet that lifts steel materials using electromagnetic force. The lifting electromagnet has an excitation coil that generates the electromagnetic force when an excitation current flows through it. If the insulation between the layers of the winding of the excitation coil is damaged by partial burnout or the like, a resistance abnormality (hereinafter referred to as a "layer short") may occur, causing a decrease in the resistance value of the excitation coil.

[0003] If the excitation coil has a resistance abnormality due to a layer short circuit, partial burnout, or the like, the resistance value of the excitation coil will be lower than that of a normal excitation coil. If the resistance value of the excitation coil is lowered due to an abnormality, the desired magnetic flux density cannot be obtained in the lifting electromagnet, and the attraction force generated by the electromagnetic force of the lifting electromagnet may be reduced.

[0004] Various diagnostic devices are known as a method for detecting an abnormality in the resistance of the excitation coil as described above. For example, Patent Document 1 discloses a diagnostic device that determines whether the excitation coil to be diagnosed is good or bad by exciting the excitation coil to be diagnosed with a diagnostic coil. The diagnostic device in Patent Document 1 is installed in a diagnostic car that runs on a track, and diagnoses a coil system for levitation and guidance of a linear motor car. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-015941 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the resistance of the excitation coil of the lifting electromagnet varies depending on the amount of steel being lifted, the temperature during operation, the frequency of use, etc. Therefore, abnormalities in resistance due to partial burnout of the excitation coil, etc., cannot be determined by the resistance value alone. Even if the diagnostic coil of the diagnostic device described in Cited Document 1 is used, from the viewpoint of workability, it is difficult to diagnose the coil resistance value of the lifting electromagnet during lifting work using the lifting electromagnet.

[0007] For the above reasons, workers may not notice a decrease in the attractive force due to an abnormality in the resistance of the exciting coil for a long period of time.

[0008] For this reason, it is desirable to efficiently detect abnormalities in the resistance of the excitation coil during lifting work using a lifting electromagnet.

[0009] An object of the present invention is to provide a lifting electromagnet abnormality diagnosis device that can efficiently detect abnormalities in the resistance of an exciting coil during lifting work using a lifting electromagnet. [Means for solving the problem]

[0010] A lifting electromagnet abnormality diagnosis device according to one embodiment of the present invention is a device for diagnosing abnormalities in a lifting electromagnet that lifts steel materials by electromagnetic force generated by current flowing through an exciting coil. The lifting electromagnet abnormality diagnosis device includes a current measurement value acquisition unit that acquires a measurement value of the current flowing through the exciting coil, and a start-up abnormality diagnosis unit that diagnoses an abnormality in the exciting coil based on a gradient of change in the current measurement value acquired by the current measurement value acquisition unit when starting to energize the exciting coil of the lifting electromagnet to positively excite the exciting coil (first configuration).

[0011] In the above-described configuration, the start-up abnormality diagnosis unit can diagnose abnormalities in the excitation coil using the gradient of the change in the current measurement value when starting to energize the excitation coil of the lifting electromagnet for positive excitation. In this case, in an excitation coil with an abnormal resistance due to a layer short or the like, the change in current relative to a change in voltage will be faster than in a normal excitation coil.

[0012] Therefore, the abnormality diagnosis unit can determine the difference in the current response at the start of energization based on the gradient of the change in the measured current value during lifting work using the lifting electromagnet.

[0013] This makes it possible to detect an abnormality in the lifting electromagnet at the start of energization by estimating an abnormality in the resistance of the excitation coil from the gradient of the change in the measured current value when energization begins.

[0014] Therefore, during lifting work using the lifting electromagnet, abnormalities in the resistance of the coil can be detected efficiently.

[0015] In the first configuration, the device further includes a maximum value abnormality diagnosis unit that compares a predetermined reference value of the current flowing through the excitation coil at a predetermined voltage with the maximum measured value of the current flowing through the excitation coil at the predetermined voltage from the start of forward excitation to the start of reverse excitation of the excitation coil to diagnose an abnormality in the excitation coil (second configuration).

[0016] This makes it possible to detect an abnormality in the lifting electromagnet using the measured values ​​during operation from the start of forward excitation to the start of reverse excitation, thereby making it possible to detect an abnormality in the lifting electromagnet at an early stage of the lifting operation using the lifting electromagnet.

[0017] In the first configuration, the device further includes a regeneration time abnormality diagnosis unit that diagnoses an abnormality in the excitation coil based on whether the regeneration time during which the current stored in the excitation coil performs a regenerative operation to circulate after the supply of the current to the excitation coil is less than a predetermined threshold value (third configuration).

[0018] An excitation coil with an abnormal resistance stores less electrical energy than a normal excitation coil. Therefore, in an excitation coil with an abnormal resistance, the regenerative current returning from the excitation coil decays quickly after the supply of current from the power source to the excitation coil is stopped. Therefore, in an excitation coil with an abnormal resistance, when the lifting electromagnet is performing a regenerative operation in which the line current returns, the regenerative time until the measured current value drops to a predetermined value is shortened. In the above-mentioned configuration, such characteristics can be used to detect an abnormality in the resistance of the excitation coil.

[0019] In the first configuration, the fourth configuration further includes a post-reverse excitation abnormality diagnosis unit that diagnoses an abnormality in the excitation coil based on whether the voltage of the excitation coil is equal to or greater than a predetermined value after the supply of current to the excitation coil is stopped and after reverse excitation of the excitation coil is completed.

[0020] An excitation coil having an abnormal resistance stores less electrical energy than a normal excitation coil. Therefore, after reverse excitation is completed, the peak voltage of the excitation coil having an abnormal resistance is lower than the peak voltage of a normal excitation coil. The above-described configuration utilizes these characteristics to accurately detect coil resistance abnormalities in the excitation coil.

[0021] A lifting electromagnet device according to one embodiment of the present invention comprises a lifting electromagnet abnormality diagnosis device having any one of the first to fourth configurations described above, and a power supply control device that controls the power supplied to the lifting electromagnet (fifth configuration).

[0022] This provides a lifting electromagnet device that can accurately diagnose abnormalities in the resistance of the lifting electromagnet. [Effects of the Invention]

[0023] A lifting electromagnet abnormality diagnosis device according to one embodiment of the present invention comprises a current measurement value acquisition unit that acquires a measurement value of the current flowing through the excitation coil of the lifting electromagnet, and a start-up abnormality diagnosis unit that diagnoses an abnormality in the excitation coil based on the gradient of the change in the measurement value of the current acquired by the current measurement value acquisition unit when current begins to be passed through the excitation coil of the lifting electromagnet in order to positively excite the excitation coil.

[0024] This allows detecting an abnormality in the lifting electromagnet by estimating an abnormality in the resistance of the excitation coil from the gradient of the change in the current measurement value when starting to energize the excitation coil, thereby enabling efficient detection of an abnormality in the coil resistance during lifting work using the lifting electromagnet. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a functional block diagram showing a schematic configuration of a lifting electromagnet abnormality diagnosis device according to the first embodiment. [Figure 2] FIG. 2 is a graph showing a schematic time progression of the voltage and current in a normal lifting electromagnet. [Figure 3] FIG. 3 is a graph showing a schematic time transition of the voltage and current in a lifting electromagnet having an abnormality in resistance. [Figure 4] FIG. 4 is a schematic diagram showing the output voltage, output current, etc. in each operation of the hoisting electromagnet device. [Figure 5] FIG. 5 is a functional block diagram showing a schematic configuration of a lifting electromagnet device equipped with a lifting electromagnet abnormality diagnosis device according to the second embodiment. [Figure 6] FIG. 6 is a schematic diagram showing output voltages, output currents, etc. in each operation of a lifting electromagnet device according to an example. [Figure 7] FIG. 7 is a schematic diagram showing output voltages and the like in each operation of a lifting electromagnet device according to another example. [Figure 8] FIG. 8 is a schematic diagram showing output voltages and the like in each operation of a lifting electromagnet device according to yet another example. DETAILED DESCRIPTION OF THE INVENTION

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0027] (Embodiment 1) 1 is a functional block diagram showing a schematic configuration of a lifting electromagnet abnormality diagnosis device 10 according to embodiment 1. The lifting electromagnet abnormality diagnosis device 10 diagnoses an abnormality in the resistance of a lifting electromagnet 90 of a lifting electromagnet device 80. The lifting electromagnet device 80 is a device for attracting steel materials to the lifting electromagnet 90 by electromagnetic force.

[0028] The lifting electromagnet device 80 includes a lifting electromagnet 90, a power supply control device 801, and a lifting electromagnet abnormality diagnosis device 10.

[0029] (Lifting electromagnet) The lifting electromagnet 90 has an exciting coil 91. When a current flows through the exciting coil 91 of the lifting electromagnet 90, an electromagnetic force for attracting the steel material is generated.

[0030] (Power supply control device) The power supply control device 801 electrically connects the power supply 70 and the excitation coil 91 of the lifting electromagnet 90. The power supply control device 801 supplies the power supplied from the power supply 70 to the lifting electromagnet 90. The power supply 70 is, for example, a generator that outputs three-phase alternating current. The power supply control device 801 controls the power supplied to the lifting electromagnet 90, thereby controlling the magnetic flux generated in the lifting electromagnet 90. This controls the attractive force of the lifting electromagnet 90.

[0031] Specifically, the power supply control device 801 includes a rectifier circuit 81 , an electric circuit 82 , an electric circuit control board 83 , a voltage measuring instrument 84 , and a current measuring instrument 85 .

[0032] The rectifier circuit 81 converts the three-phase AC supplied from the power supply 70 into DC and outputs it to the electric circuit 82 .

[0033] The electric circuit 82 controls the supply of DC power to the lifting electromagnet 90. The electric circuit 82 is electrically connected to the rectifier circuit 81 on the primary side, and is electrically connected to the excitation coil 91 of the lifting electromagnet 90 on the secondary side. The electric circuit 82 can be configured with a plurality of switching elements. The electric circuit 82 can be configured with, for example, a bridge circuit such as an H-bridge circuit. As a more specific configuration of the electric circuit 82, for example, the configuration of the electric circuit described in JP 2022-055097 A can be adopted.

[0034] The electric circuit control board 83 controls the driving of the lifting electromagnet 90 by controlling the driving of the switching elements in the electric circuit 82 during each operation of the lifting electromagnet device 80, namely, stopping, attracting, releasing and stopping.

[0035] The electrical circuit control board 83 switches the state of the electrical circuit 82 to each of the states of "circulation mode," "positive excitation," "regenerative mode and reverse excitation," and "circulation mode" according to each operation of the lifting electromagnet device 80, namely, stopping, adsorption, release, and stopping.

[0036] The circulation mode is a state in which no current flows between the power supply 70 and the electric circuit 82, and between the electric circuit 82 and the lifting electromagnet 90. That is, in the circulation mode, the excitation of the lifting electromagnet 90 is stopped. The forward excitation is a state in which the electric circuit 82 supplies power from the power supply 70 to the lifting electromagnet 90 to excite the lifting electromagnet 90 and generate an attractive force of the lifting electromagnet 90. The regeneration mode is a state in which the electrical energy stored in the excitation coil 91 of the lifting electromagnet 90 regenerates the excitation coil 91 and the electric circuit 82. Also, in the regeneration mode, the excitation of the lifting electromagnet 90 is stopped. The reverse excitation is a state in which the electric circuit 82 uses power from the power supply 70 to pass a current through the lifting electromagnet 90 in the direction opposite to that in the forward excitation state.

[0037] In the drive control, the electric circuit control board 83 uses the measured values ​​of a voltage measuring instrument 84 and a current measuring instrument 85. An operator gives instructions to the electric circuit control board 83 via an operation console 86.

[0038] A voltage meter 84 measures the voltage (hereinafter referred to as "output voltage V1") on the output side of the electric circuit 82. A current meter 85 measures the current (hereinafter referred to as "output current I1") flowing from the electric circuit 82 to the excitation coil 91 of the lifting electromagnet 90. The arrow accompanying I1 in Fig. 1 indicates the direction of the current in the positive excitation state.

[0039] (Lifting electromagnet abnormality diagnostic device) The lifting electromagnet abnormality diagnosis device 10 includes a measurement value acquisition unit 11 as a current measurement value acquisition unit, a start-up abnormality diagnosis unit 12, and a notification unit 13.

[0040] The measurement value acquiring unit 11 acquires the measurement value of the output voltage V1 from the voltage measuring instrument 84 and also acquires the measurement value of the output current I1 from the current measuring instrument 85.

[0041] The start-up abnormality diagnosis unit 12 diagnoses an abnormality in the resistance of the lifting electromagnet 90 based on the measured values ​​of the output voltage V1 and the output current I1. The start-up abnormality diagnosis unit 12 will be described in detail later.

[0042] When the diagnosis result of the start-up abnormality diagnosis unit 12 is "abnormal," the notification unit 13 notifies a worker or the like of the diagnosis result. The notification unit 13 may output a signal for notification to the outside. The notification unit 13 may also display the diagnosis result on a display or the like connected to the lifting electromagnet device 80.

[0043] (Details of the start-up abnormality diagnosis section) Fig. 2 is a graph showing a schematic time progression of the output voltage V1 and output current I1 in a normal lifting electromagnet 90. Fig. 3 is a graph showing a schematic time progression of the output voltage V1 and output current I1 in a lifting electromagnet 90 having an abnormality in resistance. Fig. 4 is a schematic diagram showing the output voltage V1, output current I1, etc. in each operation of the lifting electromagnet device 80.

[0044] 2 to 4, the details of the start-up abnormality diagnosis unit 12 will be described. When a resistance abnormality occurs in the lifting electromagnet 90, the inductance of the exciting coil 91 decreases, causing a change in the output voltage V1 and output current I1 to the lifting electromagnet 90.

[0045] Comparing the graph of the output voltage V1 and output current I1 in a normal state shown in Fig. 2 with the graph of the output voltage V1 and output current I1 in an abnormal state shown in Fig. 3, the responsiveness of the output current I1 to the output voltage V1 during the chucking operation at the start of operation of the lifting electromagnet 90 is higher in an abnormal state than in a normal state. Therefore, in the rising section of the output voltage V1 at the start of operation of the lifting electromagnet 90, the slope α2 of the output current I1 in an abnormal state is larger than the slope α1 of the output current I1 in a normal state.

[0046] Therefore, the start-up abnormality diagnosis unit 12 can determine whether there is an abnormality in the resistance based on the gradient of the output current I1 in the rising section of the output voltage V1 when the lifting electromagnet 90 starts operating.

[0047] Specifically, referring particularly to FIG. 4, the lifting electromagnet device 80 starts a chucking operation when the operation signal is turned on. The chucking operation includes an over-excitation operation and a subsequent constant excitation operation. During the chucking operation, the state of the electrical circuit switches to a positive excitation state. After the operation signal is turned on, the lifting electromagnet device 80 starts energizing the lifting electromagnet 90 and measures the output voltage V1 and output current I1. During the over-excitation operation for a predetermined period from the start of operation, the lifting electromagnet device 80 controls the output voltage V1 to reach the over-excitation voltage V11, and during the constant excitation operation after the over-excitation operation, controls the output voltage V1 to reach the constant excitation voltage V12.

[0048] Based on the measured values ​​of the output voltage V1 and the output current I1, the start-up abnormality diagnosis unit 12 detects a voltage steepness section T211 during which the output voltage V1 converges from 0 V at the start of operation of the lifting electromagnet 90 to the over-excitation voltage V11 during a measurement period T21 from when the operation signal is turned on until the reverse excitation signal is turned on. The measurement period T21 is a period during positive excitation that includes over-excitation operation and constant excitation operation. The start-up abnormality diagnosis unit 12 may determine whether the output voltage V1 has converged to the over-excitation voltage V11 based on whether the output voltage V1 exceeds a predetermined over-excitation voltage threshold. The start-up abnormality diagnosis unit 12 calculates a current gradient α21 during the voltage steepness section T211.

[0049] Furthermore, the start-up abnormality diagnosis unit 12 detects a maximum current I11 during the measurement period T21 based on the measured values ​​of the output voltage V1 and the output current I1. The start-up abnormality diagnosis unit 12 detects a maximum current section T212 from 0 V at the start of operation of the lifting electromagnet 90 until the maximum current I11 is detected. The start-up abnormality diagnosis unit 12 calculates a current gradient α22 during the maximum current section T212.

[0050] Next, the start-up abnormality diagnosis unit 12 calculates the gradient magnification factor K1 by the following equation (1). K1=α21 / α22 (1) The gradient magnification K1 is the magnification of the gradient α21 of the current in the steep voltage section T211 relative to the gradient α22 of the current in the maximum current section T212.

[0051] The start-up abnormality diagnosis unit 12 diagnoses whether or not the slope (gradient of change in the current measurement value) of the output current I1 at the start of operation is abnormal based on the slope magnification factor K1. If the slope magnification factor K1 exceeds a predetermined slope abnormality threshold, the start-up abnormality diagnosis unit 12 diagnoses that the slope of the output current I1 at the start of operation is "abnormal," and if the slope magnification factor K1 is equal to or less than the slope abnormality threshold, the start-up abnormality diagnosis unit 12 diagnoses that the slope of the output current I1 at the start of operation is "normal (normal)."

[0052] In the above-described configuration, the start-up abnormality diagnosis unit 12 diagnoses abnormalities in the excitation coil 91 by using the gradient of the change in the measured value of the output current I1 when current begins to be applied to the excitation coil 91 of the lifting electromagnet 90 in order to positively excite the excitation coil 91.

[0053] If the excitation coil 91 has a resistance abnormality due to a layer short or the like, the coil resistance value will be lower than that of a normal excitation coil. In an excitation coil 91 having such an abnormality in resistance, the change in current relative to voltage will be faster than in a normal excitation coil 91.

[0054] The start-up abnormality diagnosis unit 12 can determine the difference in responsiveness at the start of energization when the lifting electromagnet 90 is performing a lifting operation, based on the gradient of the change in the measured value of the output current I1.

[0055] As a result, when current begins to be applied to the excitation coil 91 for positive excitation, an abnormality in the resistance of the excitation coil 91 can be estimated from the gradient of the change in the measured value of the output current I1, thereby detecting an abnormality in the lifting electromagnet 90 at the start of current application.

[0056] Therefore, at the start of the lifting operation by the lifting electromagnet 90, an abnormality in resistance can be detected efficiently.

[0057] (Embodiment 2) Fig. 5 is a functional block diagram showing a schematic configuration of a lifting electromagnet device 800 equipped with a lifting electromagnet abnormality diagnosis device 102 according to embodiment 2. Fig. 6 is a schematic diagram showing output voltages and output currents in each operation of the lifting electromagnet device 800 according to an example. The lifting electromagnet abnormality diagnosis device 102 according to embodiment 2 differs from the lifting electromagnet abnormality diagnosis device 10 according to embodiment 1 in that it has a diagnosis mode abnormality diagnosis unit 14. In the following, the same components as those in embodiment 1 are denoted by the same reference numerals and their description will be omitted, and only the components different from embodiment 1 will be described.

[0058] The lifting electromagnet device 800 includes a lifting electromagnet 90, a power supply control device 801, and a lifting electromagnet abnormality diagnosis device 102.

[0059] The lifting electromagnet abnormality diagnostic device 102 has a measurement value acquisition unit 11, a start-up abnormality diagnostic unit 12, a diagnostic mode abnormality diagnostic unit 14 as a maximum value abnormality diagnostic unit, and a notification unit 13.

[0060] When the lifting electromagnet abnormality diagnosis device 102 operates in the diagnosis mode, the diagnostic mode abnormality diagnosis unit 14 compares a predetermined current reference value K2 flowing through the excitation coil 91 at a predetermined voltage with a rated current maximum value MRI1, which is the maximum measured value of the output current I1 flowing through the excitation coil 91 at the predetermined voltage from the start of forward excitation to the start of reverse excitation of the excitation coil 91, to diagnose an abnormality in the excitation coil 91.

[0061] The diagnostic mode is a mode in which the lifting electromagnet 90 of the lifting electromagnet abnormality diagnostic device 102 is operated under no load and with the temperature within a certain range in order to diagnose abnormalities in resistance. An operator can set the lifting electromagnet abnormality diagnostic device 102 to the diagnostic mode by operating the operation console 86. During the diagnostic mode, an ON signal indicating that diagnosis is in progress is output from the lifting electromagnet abnormality diagnostic device 102 or the electric circuit control board 83.

[0062] Referring again to Figures 2 and 3, when the graph of the output voltage V1 and output current I1 in a normal state shown in Figure 2 is compared with the graph of the output voltage V1 and output current I1 in an abnormal state shown in Figure 3, it is found that during adsorption operation, the maximum rated current value MRI2 in an abnormal state is greater than the maximum rated current value MRI1 in a normal state.

[0063] Specifically, the diagnostic mode abnormality diagnoser 14 detects a maximum rated current value MRI2, which is the maximum value of the output current I1 during a measurement period T22, based on the measured values ​​of the output voltage V1 and the output current I1. The measurement period T22, from when the signal during operation is turned on until the signal during reverse excitation is turned on, is the period during which the rated current flows through the excitation coil 91 in a positive excitation state including overexcitation operation and constant excitation operation.

[0064] The abnormality diagnosis unit 14 diagnoses whether or not an abnormality exists depending on whether the maximum rated current MRI2 exceeds a predetermined current reference value K2. The predetermined current reference value K2 is based on the maximum rated current MRI1 that flows in a normal lifting electromagnet 90.

[0065] The predetermined current reference value K2 may be a value that takes into account a margin of the maximum rated current MRI1. For example, the predetermined current reference value K2 can be set to a value that is 10% greater than the maximum rated current MRI1.

[0066] The diagnostic mode abnormality diagnostic unit 14 diagnoses "abnormality" when the detected maximum rated current value MRI2 exceeds a predetermined current reference value K2 (MRI2>K2), and diagnoses "no abnormality (normal)" when the maximum rated current value MRI2 is equal to or less than the predetermined current reference value K2 (MRI2≦K2).

[0067] This allows for accurate detection of abnormalities in the lifting electromagnet 90 using measured values ​​during operation from the start of forward excitation to the start of reverse excitation. Therefore, abnormalities in the lifting electromagnet 90 can be detected at an early stage of operation.

[0068] The lifting electromagnet device 800 also includes a lifting electromagnet abnormality diagnostic device 102, a lifting electromagnet 90, and a power supply control device 801. This provides the lifting electromagnet device 800 that can accurately diagnose abnormalities in the resistance of the lifting electromagnet 90.

[0069] (Modification 1 of Embodiment 2) 7 is a schematic diagram showing the output voltage V1 and the like in each operation of another example of a lifting electromagnet device 800. In the lifting electromagnet abnormality diagnosis device 102 according to the first modification of the second embodiment, the diagnosis mode abnormality diagnosis unit 14 functions as a regeneration time abnormality diagnosis unit.

[0070] Referring to FIG. 7 in addition to FIG. 2, FIG. 3, and FIG. 5, the diagnostic mode abnormality diagnosis unit 14 according to the first modification diagnoses an abnormality in the excitation coil 91 based on whether or not the regenerative operation in which a current circulates due to the electrical energy stored in the excitation coil 91 is performed after the supply of the output current I1 to the excitation coil 91 is stopped, is equal to or less than a predetermined threshold value.

[0071] An exciting coil 91 having an abnormal resistance stores less electrical energy than a normal exciting coil 91. For this reason, as can be seen from a comparison between the graph of the output voltage V1 and output current I1 in a normal state shown in Fig. 2 and the graph of the output voltage V1 and output current I1 in an abnormal state shown in Fig. 3, during the regenerative operation in the release operation, the output current decays faster in an abnormal state than in a normal state. For this reason, the regenerative time until the output current drops to a predetermined current value is shorter in an abnormal state than in a normal state (in Figs. 2 and 3, the regenerative time in a normal state is indicated by "RT1") and the regenerative time in an abnormal state is indicated by "RT2").

[0072] The diagnostic mode abnormality diagnosis unit 14 detects a regeneration time T231 during a measurement period T23 during the release operation from when the signal during reverse excitation is turned on to when the signal during reverse excitation is turned off. As will be described below, the diagnostic mode abnormality diagnosis unit 14 detects the time until the measured value of the output current I1 during the release operation decreases to a predetermined value as the regeneration time T231.

[0073] In the release operation, the electric circuit 82 switches between two states, a regenerative mode state and a reverse excitation state, in sequence.

[0074] In the regeneration mode, the power supply from the power supply 70 to the lifting electromagnet 90 is stopped in order to wait for the regenerative current of the exciting coil 91 to decay. As described above, in the regeneration mode, the electric energy stored in the exciting coil 91 causes the lifting electromagnet 90 to regenerate current to the electric circuit 82. As a result, the measured value of the output voltage V1 decreases and becomes negative. Furthermore, the output current I1 reaches 0 A due to the decay of the regenerative current.

[0075] The next reverse excitation state is a state in which a current in the opposite direction to the positive excitation state is passed through the hoisting electromagnet 90 in order to demagnetize the residual magnetic force of the hoisting electromagnet 90 as described above. When the output current I1 decreases to 0 A during the regeneration mode state, the electric circuit control board 83 increases the output voltage V1 of the electric circuit 82 in order to switch the state of the electric circuit 82 to the reverse excitation state.

[0076] When the output voltage V1, which transitions negatively after the signal during reverse excitation is turned on, reaches a predetermined reference voltage V31, the diagnosis mode abnormality diagnosis unit 14 determines that the regeneration time T231 has ended. That is, the predetermined reference voltage V31 can distinguish between the state of waiting for current decay during regeneration and the reverse excitation state.

[0077] The diagnosis mode abnormality diagnosis unit 14 diagnoses the presence or absence of an abnormality according to whether the regeneration time T231 until the end of the regeneration time T231 is less than a predetermined time reference value (predetermined threshold value) K3 after the signal during reverse excitation is turned on.

[0078] The predetermined time reference value K3 may be a value obtained by considering a margin rate for the normal regeneration time RT1. For example, the predetermined time reference value K3 can be set to a value of -10% of the normal regeneration time RT1.

[0079] When the detected regeneration time T231 is less than the predetermined time reference value K3 (T231 < K3), the diagnosis mode abnormality diagnosis unit 14 diagnoses that "there is an abnormality", and when the regeneration time T231 is greater than or equal to the predetermined time reference value K3 (T231 ≥ K3), it diagnoses that "there is no abnormality (normal)".

[0080] In the above configuration, based on whether the regeneration time T231 is less than or equal to the time reference value K3, an abnormality in the resistance of the excitation coil 91 can be accurately detected.

[0081] (Modification 2 of Embodiment 2) 8 is a schematic diagram showing the output voltage V1 and the like in each operation of a lifting electromagnet device 800 according to yet another example. In the lifting electromagnet abnormality diagnosis device 102 according to the second modification of the second embodiment, the diagnosis mode abnormality diagnosis unit 14 functions as a post-reverse excitation abnormality diagnosis unit.

[0082] 2, 3, and 5, and also referring to Fig. 8, the diagnostic mode abnormality diagnosing unit 14 according to Modification 2 acquires a measured value of the output voltage V1 during a measurement period T24 from when the signal during reverse excitation is turned on, through the signal during reverse excitation being turned off and stopped, until the output voltage V1 converges to a predetermined stop voltage value near 0 V. The diagnostic mode abnormality diagnosing unit 14 diagnoses an abnormality in the exciting coil 91 based on the output voltage V1 during the measurement period T24.

[0083] As shown in Figures 2 and 3, during the stopping operation after the release operation, a regenerative voltage is generated due to reverse excitation. The waveform of the regenerative voltage generated by reverse excitation differs between normal and abnormal conditions. For example, the regenerative voltage RV2 after reverse excitation during an abnormal condition shown in Figure 3 is lower than the regenerative voltage RV1 after reverse excitation during normal conditions shown in Figure 2.

[0084] Referring particularly to FIG. 8, the diagnostic mode abnormality diagnosis unit 14 diagnoses an abnormality in the excitation coil 91 based on whether the output voltage V1 is equal to or greater than a predetermined post-reverse excitation regenerative voltage threshold V41 during a measurement period T24 after the signal is turned on during reverse excitation. The post-reverse excitation regenerative voltage threshold V41 can be set based on the post-reverse excitation regenerative voltage RV1 in a normal state. The post-reverse excitation regenerative voltage threshold V41 can be set to a value that is equal to or less than the post-reverse excitation regenerative voltage RV1 in a normal state and equal to or greater than the post-reverse excitation regenerative voltage RV2 in an abnormal state, for example. The post-reverse excitation regenerative voltage threshold V41 can be set to a value that is 70% to 90% of the post-reverse excitation regenerative voltage RV1 in a normal state, taking into account a margin of error.

[0085] Further, the diagnostic mode abnormality diagnostic unit 14 may diagnose an abnormality of the exciting coil 91 by further using the regenerative voltage peak time after reverse excitation during the measurement period T24. After an off signal during operation is output, the diagnostic mode abnormality diagnostic unit 14 detects the time when the output voltage V1 reaches the regenerative voltage threshold V41 after reverse excitation as the start time of the regenerative voltage peak out time T241 after reverse excitation.

[0086] Further, after the start time of the regenerative voltage peak out time T241 after reverse excitation, the diagnostic mode abnormality diagnostic unit 14 detects the time when the output voltage V1 changes from the regenerative voltage threshold V41 to the peak out voltage threshold V42 as the end time of the regenerative voltage peak out time T241 after reverse excitation.

[0087] The peak out voltage threshold V42 can be set based on the regenerative voltage threshold V41 after reverse excitation. The peak out voltage threshold can be set, for example, to a value of 70% to 90% of the regenerative voltage threshold V41 after reverse excitation in consideration of a margin rate.

[0088] The diagnostic mode abnormality diagnostic unit 14 diagnoses the presence or absence of an abnormality according to whether the regenerative voltage peak out time T241 after reverse excitation detected as described above is less than a predetermined time reference value K4 (predetermined threshold).

[0089] The predetermined time reference value K4 may be a value obtained by considering a margin rate for the regenerative voltage peak out time after normal reverse excitation. For example, the predetermined time reference value K4 can be set to a value of -10% of the regenerative voltage peak out time after normal reverse excitation.

[0090] When the detected regenerative voltage peak out time T241 after reverse excitation is less than the predetermined time reference value K4 (T241 < K4), the diagnostic mode abnormality diagnostic unit 14 diagnoses "abnormality exists", and when the regenerative voltage peak out time T241 after reverse excitation is greater than or equal to the predetermined time reference value K4 (T241 ≥ K4), it diagnoses "no abnormality (normal)".

[0091] The diagnostic mode abnormality diagnostic unit 14 may diagnose an abnormality in the exciting coil 91 only by determining the regenerative voltage peak-out time T241 after reverse excitation.

[0092] In the above-described configuration, an abnormality in the resistance of the excitation coil 91 can be detected with high accuracy based on the waveform of the regenerative voltage generated by the reverse excitation.

[0093] (Other embodiments) Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and it is possible to appropriately modify the above-described embodiments within the scope of the spirit of the present invention.

[0094] In each of the above embodiments, the power supply 70 is a generator that outputs three-phase AC power, but the power supply may also be a battery that outputs DC power at a predetermined voltage, or any other power supply device.

[0095] It is also possible to combine the first embodiment, the second embodiment, and their modifications 1 and 2. For example, in a lifting electromagnet abnormality diagnosis device having the start-up abnormality diagnosis unit of the first embodiment and the diagnosis mode abnormality diagnosis unit of the second embodiment and its modifications 1 and 2, if either the start-up abnormality diagnosis unit or the diagnosis mode abnormality diagnosis unit outputs a diagnosis result of "abnormality present," the lifting electromagnet abnormality diagnosis device may output a final result of "abnormality present."

[0096] Furthermore, for example, the lifting electromagnet abnormality diagnostic device may output a final "abnormality present" by weighting the respective diagnostic results of the start-up abnormality diagnostic section or the diagnostic mode abnormality diagnostic section.

[0097] The lifting electromagnet abnormality diagnostic device may output a final result of "no abnormality" only when all of the diagnostic results of the start-up abnormality diagnostic section or the diagnostic mode abnormality diagnostic section are "no abnormality."

[0098] In each of the above-described embodiments, the lifting electromagnet device 80, 800 has one lifting electromagnet 90 and one electric circuit 82. However, the lifting electromagnet device may have two or more lifting electromagnets and two or more electric circuits.

[0099] In each of the above embodiments, the lifting electromagnet device 80, 800 includes a lifting electromagnet 90, a power supply control device 801, and a lifting electromagnet abnormality diagnosis device 10, 102. However, the lifting electromagnet abnormality diagnosis device may be a device independent of the lifting electromagnet device. For example, the electromagnet abnormality diagnosis device may be retrofitted to a lifting electromagnet device that includes a lifting electromagnet and a power supply control device.

[0100] In the first embodiment, the start-up abnormality diagnosis unit 12 calculates the gradient magnification factor K1 based on the measured values ​​of the output voltage V1 and the output current I1 to diagnose an abnormality in the resistance of the lifting electromagnet 90. However, the start-up abnormality diagnosis unit may also determine the gradient of the current based on the measured value of the output current.

[0101] In the second embodiment, the diagnostic mode abnormality diagnosing unit 14 diagnoses an abnormality in the exciting coil 91 during the diagnostic mode. However, the diagnostic mode abnormality diagnosing unit may diagnose an abnormality in the exciting coil even when not in the diagnostic mode.

[0102] Although not specifically described in the above embodiments, the sampling period of the measurement values ​​acquired by the voltage measuring instrument and the current measuring instrument can be set arbitrarily. Since the voltage steep section in embodiment 1 is a very short period, the lifting electromagnet abnormality diagnosis device in embodiment 1 may set a shorter sampling period compared to embodiment 2, etc. [Industrial Applicability]

[0103] The present invention can be used in a lifting electromagnet abnormality diagnosis device that diagnoses a lifting electromagnet that lifts steel materials by electromagnetic force generated by current flowing through an exciting coil. [Explanation of symbols]

[0104] 10, 102: Lifting electromagnet abnormality diagnosis device 11: Measurement value acquisition section 12: Start-up abnormality diagnosis section 13: Information Department 14: Diagnostic mode abnormality diagnosis section 70: Power supply 80, 800: Hanging electromagnet device 801: Power supply control device 81: Rectifier circuit 82: Electrical Circuits 83: Electric circuit control board 84: Voltage measuring instrument 85: Current measuring instrument 86:Operation console 90: Lifting electromagnet 91: Excitation coil I1: Output current I11: Maximum current MRI1, MRI2: Maximum rated current RV1, RV2: Regenerative voltage after reverse excitation V1: Output voltage V11: Over-excitation voltage V12: Constant excitation voltage V31: Reference voltage V41: Regenerative voltage threshold after reverse excitation V42: Peak out voltage threshold

Claims

1. A lifting electromagnet abnormality diagnosis device that performs abnormality diagnosis on a lifting electromagnet that lifts steel materials by electromagnetic force generated by current flowing through an exciting coil, a current measurement value acquisition unit that acquires a measurement value of a current flowing through the excitation coil; a start-up abnormality diagnosis unit that diagnoses an abnormality in the excitation coil based on a gradient of change in the current measurement value acquired by the current measurement value acquisition unit when starting to energize the excitation coil of the lifting electromagnet in order to positively excite the excitation coil; having Lifting electromagnet abnormality diagnostic device.

2. 2. The lifting electromagnet abnormality diagnosis device according to claim 1, The present invention further includes a maximum value abnormality diagnosing unit that compares a predetermined reference value of a current flowing through the excitation coil at a predetermined voltage with a maximum value of a measured value of the current flowing through the excitation coil at the predetermined voltage from the start of forward excitation to the start of reverse excitation of the excitation coil, and diagnoses an abnormality in the excitation coil. Lifting electromagnet abnormality diagnostic device.

3. 2. The lifting electromagnet abnormality diagnosis device according to claim 1, The motor further includes a regeneration time abnormality diagnosis unit that diagnoses an abnormality in the excitation coil based on whether a regeneration time during which a regeneration operation in which the current stored in the excitation coil circulates after the supply of the current to the excitation coil is stopped is equal to or less than a predetermined threshold. Lifting electromagnet abnormality diagnostic device.

4. 2. The lifting electromagnet abnormality diagnosis device according to claim 1, The motor further includes a post-reverse excitation abnormality diagnosis unit that diagnoses an abnormality in the excitation coil based on whether a voltage of the excitation coil is equal to or greater than a predetermined value after the supply of the current to the excitation coil is stopped and after the reverse excitation of the excitation coil is completed. Lifting electromagnet abnormality diagnostic device.

5. The lifting electromagnet abnormality diagnosis device according to any one of claims 1 to 4, The lifting electromagnet; a power supply control device that controls power supplied to the lifting electromagnet; having Hanging electromagnet device.

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