Control device for hung-up electromagnet and hung-up electromagnet device including the same

Abstract

To provide a control device for a hung-up electromagnet which can accurately detect falling of a steel plate hung up by a hung-up electromagnet, without being affected by a skill of an operator.SOLUTION: A control device 1 for a hung-up electromagnet controls an electric circuit 4 for driving a hung-up electromagnet 2 for hanging up a steel plate by electromagnetic force. The control device 1 for the hung-up electromagnet has: a current control part 10 for controlling a current flowing in the electric circuit 4 so as to lower an excitation current flowing in the hung-up electromagnet 2, when falling the steel plate hung up by the hung-up electromagnet 2; an excitation current detection part 20 for detecting the excitation current flowing in the hung-up electromagnet 2, when the current flowing in the electric circuit 4 is controlled by the current control part 10; and a steel plate falling detection part 30 for detecting falling of a steel plate hung up by the hung-up electromagnet 2, on the basis of the excitation current detected by the excitation current detection part 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention controls an electric circuit that drives a lifting electromagnet that lifts a steel plate by electromagnetic force. The present invention relates to a lifting electromagnet control device and a lifting electromagnet device equipped with the same. [Background technology]

[0002] A lifting electromagnet that controls the electric circuit that drives the lifting electromagnet that lifts the steel plate by electromagnetic force. Such a control device for a hoisting electromagnet is known. 1 includes a lifting electromagnet and a magnetic circuit formed in a steel plate lifted by the lifting electromagnet. The detection output of a magnetic flux detector that detects the magnetic flux in the suspension is used to detect the adhesion and detachment of the steel plate. A steel plate attraction / detachment detection device for an upper electromagnet is known.

[0003] The steel plate attraction / detachment detection device detects a pulse signal obtained by differentiating the detection output of the magnetic flux detector. The number of adhesions or detachments of the steel plates is determined by counting the number of adhesions or detachments of the steel plates according to their polarity. It is equipped with a separation detection circuit.

[0004] This allows the operator to operate the selection control of the number of sheets to be attracted or the suspension failure correction control between the lifting electromagnets. Compared to relying on the intuition of the operator, it is now possible to perform easy and accurate control, improving safety and This will improve work efficiency. Also, the operator can visually check the adhesion and release of the steel plate. Since it can detect automatically without any trouble, it is possible to check the change in the number of adsorbed steel plates. can. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 59-24717 Summary of the Invention [Problem to be solved by the invention]

[0006] When a steel plate attracted to a lifting electromagnet falls, the steel plate is pulled by the lifting electromagnet. When the magnetic flux of the magnetic circuit formed by the lifting electromagnet starts to change, Therefore, the change in magnetic flux in the magnetic circuit occurs before the steel plate falls. The magnetic flux generated when the steel plate is peeled off from the lifting electromagnet is The change is gradual, and it is difficult to detect the change in the magnetic flux with high accuracy. In the steel plate attraction / detachment detection device of Patent Document 1, the falling of a steel plate against a lifting electromagnet is detected by detecting It is difficult to accurately detect the timing of the fall.

[0007] Here, the lifting electromagnet lifts up a plurality of steel plates, and the lowest layer is When only the steel plate is dropped, the excitation current flowing through the lifting electromagnet is reduced to the lowest level. After the steel plate is dropped, a predetermined excitation current is passed through the hoisting electromagnet to generate a magnetic flux. Therefore, it is necessary to attract the other steel plate to the lifting electromagnet again. It is necessary to predict the timing when the steel plate will fall from the electromagnet and to pass the excitation current to the lifting electromagnet. Therefore, the operator's skills were required to operate the hoisting electromagnet device.

[0008] In contrast, the steel plate being lifted by the lifting electromagnet is not affected by the skill of the operator. In order to accurately control the number of steel plates, a device that can detect the falling of steel plates with high accuracy is required. It is being read.

[0009] The object of the present invention is to provide a lifting electromagnet that can lift a vehicle without being affected by the skill of the operator. The present invention aims to provide a control device for a hoisting electromagnet that can accurately detect the fall of a suspended steel plate. [Means for solving the problem]

[0010] The lifting electromagnet control device according to one embodiment of the present invention lifts a steel plate by electromagnetic force. This is a lifting electromagnet control device that controls the electric circuit that drives the lifting electromagnet. The control device for the stone is configured to control the front and rear of the steel plate when the steel plate lifted by the lifting electromagnet is dropped. The current flowing through the electric circuit is controlled so as to reduce the exciting current flowing through the hoisting electromagnet. a current control unit, and when the current control unit controls a current flowing through the electric circuit, an excitation current detection unit for detecting an excitation current flowing through the hoisting electromagnet; Based on the excitation current detected by the lifting electromagnet, and a steel plate drop detection unit that detects the drop of the steel plate (first configuration).

[0011] When the steel plate lifted by the lifting electromagnet is dropped, the current control unit When the steel plate falls against the lifting electromagnet, the exciting current flowing through the lifting electromagnet is reduced. When the lifting magnet is lowered, an induced current flows in the lifting electromagnet due to the change in magnetic flux. The excitation current flowing through the electromagnet increases temporarily. This occurs when the steel plate is dropped, and is larger than the change in magnetic flux caused by the drop of the steel plate.

[0012] Therefore, the above-mentioned change in the excitation current is detected by the excitation current detection unit, and the detected change in the excitation current is The steel plate drop detection unit detects the drop of the steel plate based on the excitation current, and the lifting electromagnetic The falling of the steel plate against a stone can be detected with high accuracy.

[0013] Moreover, by detecting a change in the excitation current flowing through the lifting electromagnet, Since the falling of the steel plate against the stone can be detected, it is not dependent on the skill of the operator who operates the lifting electromagnet device. The drop of the steel plate can be detected without being affected by the impact.

[0014] Therefore, with the above-mentioned configuration, the lifting electromagnet can be operated without being affected by the skill of the operator. Therefore, the fall of the lifted steel plate can be detected with high accuracy.

[0015] In the first configuration, the steel plate drop detection unit detects a change in the excitation current per unit time. When the polarity of the amount of excitation changes or when the peak value of the excitation current is detected, The fall of a steel plate suspended by an upper electromagnet is detected (second configuration).

[0016] This makes it possible to detect changes in the excitation current flowing through the hoisting electromagnet with high accuracy. Therefore, the drop of the steel plate onto the lifting electromagnet is controlled by the excitation current flowing through the lifting electromagnet. This allows for highly accurate detection.

[0017] In the first or second configuration, the current control unit is suspended by the lifting electromagnet. When the lifted steel plate is dropped, the electric circuit is caused to supply a low exciting current to the lifting electromagnet. A discharge circuit is formed to lower the voltage (third configuration).

[0018] As a result, when the steel plate lifted by the lifting electromagnet is dropped, The excitation current of the lifting electromagnet can be reduced by the discharge circuit. The configuration for reducing the magnet excitation current can be achieved with a simple structure.

[0019] In the first or second configuration, the current control unit is suspended by the lifting electromagnet. When the lifted steel plate is dropped, the exciting current of the lifting electromagnet is reduced. The current supplied to the electric circuit is adjusted (fourth configuration).

[0020] As a result, when the steel plate lifted by the lifting electromagnet is dropped, By adjusting the current supplied to the circuit, the excitation current of the lifting electromagnet can be easily reduced. It is possible to do so.

[0021] In any one of the first to fourth configurations, the excitation current detection unit is One of the plurality of lifting electromagnets electrically connected in parallel to the power source via the electric circuit The steel plate drop detection unit detects the excitation current flowing through one of the lifting electromagnets. The lifting electromagnet is used to lift the load based on the excitation current detected by the lifting electromagnet. The fifth configuration detects the fall of a steel plate that is being held in place.

[0022] In this way, when a plurality of lifting electromagnets are electrically connected in parallel to the power source, The electrical resistance of the multiple lifting electromagnets varies due to temperature variations in the multiple lifting electromagnets. This causes variation in the excitation current flowing through the multiple lifting electromagnets. Then, the magnetic flux generated by the multiple lifting electromagnets also changes for each lifting electromagnet. There is also variation in the adhesive force of the steel plate depending on the number of lifting electromagnets.

[0023] In such a case, in the above-mentioned configuration, one of the plurality of lifting electromagnets An excitation current flowing through a magnet is detected, and the one hoisting electromagnet is The falling of the steel plate being lifted by the plurality of lifting electromagnets is detected. In this method, the falling of the steel plate is detected with high accuracy according to the variation in the electric resistance of each lifting electromagnet. It is possible.

[0024] The lifting electromagnet device according to one embodiment of the present invention has any one of the first to fifth configurations described above. A lifting electromagnet control device having one or more configurations, the lifting electromagnet, and the electric circuit. (6th configuration).

[0025] This provides a lifting electromagnet device capable of detecting the fall of a steel plate relative to the lifting electromagnet with high accuracy. can be done. Effect of the Invention

[0026] The lifting electromagnet control device according to one embodiment of the present invention is a device for controlling a lifting electromagnet lifted by the lifting electromagnet. When the steel plate is dropped, an electric current is applied to the lifting electromagnet so as to reduce the exciting current. a current control unit for controlling a current flowing through a circuit; An excitation current detection unit that detects an excitation current flowing through the lifting electromagnet when controlling the current flowing through the lifting electromagnet. and based on the excitation current detected by the excitation current detection unit, Thus, it has a steel plate drop detection unit that detects the drop of the steel plate being lifted.

[0027] This allows the change in excitation current that occurs when the steel plate falls against the hoisting electromagnet to be The excitation current is detected by the excitation current detection unit. Based on this, the steel plate drop detection unit can detect the drop of the steel plate. The drop of the steel plate against the lifting electromagnet can be controlled with high accuracy without being affected by the skill of the operator. It can be detected quickly. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a control circuit diagram showing a schematic configuration of a hoisting electromagnet device equipped with a hoisting electromagnet control device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing changes in the excitation current flowing through the lifting electromagnet and changes in the magnetic flux when a steel plate attracted to the lifting electromagnet falls. [Diagram 3] FIG. 3 is a diagram showing the relationship between the changes in excitation current and magnetic flux and the behavior of a steel plate when the steel plate falls from a hoisting electromagnet. [Figure 4] FIG. 4 is a flowchart showing the operation of the lifting electromagnet control device to detect the drop of a steel plate. [Diagram 5] FIG. 5 is a control circuit diagram showing a schematic configuration of a hoisting electromagnet device including a hoisting electromagnet control device according to the second embodiment. [Figure 6] FIG. 6 is a control circuit diagram showing a schematic configuration of a hoisting electromagnet device including a hoisting electromagnet control device according to the third embodiment. [Figure 7] FIG. 7 is a control circuit diagram showing a current flow when a lifting electromagnet control device according to a modification of the third embodiment supplies power from a power source to the lifting electromagnet. [Figure 8] FIG. 8 is a control circuit diagram showing a current flow when the lifting electromagnet control device according to the modified example of the third embodiment is discharging the lifting electromagnet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same reference numerals are used for the parts and their descriptions will not be repeated.

[0030] (Embodiment 1) FIG. 1 is a diagram showing a lifting electromagnet device X equipped with a lifting electromagnet control device 1 according to a first embodiment of the present invention. This is a control circuit diagram showing a schematic configuration of the lifting electromagnet device X1. The magnetic flux generated by the magnetic field attracts the steel plate M (see FIG. 4) to the lifting electromagnet 2. .

[0031] As shown in FIG. 1, in the lifting electromagnet device X, an electric circuit is By controlling the driving of 4, power is supplied from the power source 3 to the lifting electromagnet 2. In the magnet device X1, the power supplied to the lifting electromagnet 2 is controlled to generate a magnetic field. Therefore, the driving of the electric circuit 4 is controlled by the lifting electromagnet control device 1. By controlling this, the magnetic attraction force of the hoisting electromagnet 2 is controlled.

[0032] The lifting electromagnet device X1 of this embodiment includes a lifting electromagnet 2 and a power supply for the lifting electromagnet 2. and a lifting electromagnet control device 1 that controls the operation of the electric circuit 4. do.

[0033] The electric circuit 4 electrically connects the power source 3 and the lifting electromagnet 2. The electric circuit 4 includes a pair of open The power supply 3 has switches 41 and 42, a discharge circuit 43, and a current detector 44. It outputs DC power.

[0034] Each of the pair of switches 41 and 42 is, for example, an electromagnetic switch or an electromagnetic contactor. One of the pair of switches 41 and 42, switch 41, is connected to the positive side power supply line P of the power supply 3 and the suspension The other switch 42 electrically connects or disconnects the electromagnet 2 to the negative side of the power supply 3. The pair of switches 41 and 42 electrically connect or disconnect the inlet N and the lifting electromagnet 2. They simultaneously perform opening and closing operations in response to a drive signal output from the upper electromagnet control device 1.

[0035] When the pair of switches 41 and 42 are closed, the power supply 3 supplies the lifting electromagnet through the electric circuit 4. When the pair of switches 41 and 42 are open, the power source 3 supplies DC power to the lifting device 2. No DC power is supplied to the electromagnet 2. Therefore, the pair of switches 41 and 42 are suspended from the power source 3. The supply of DC power to the upper electromagnet 2 is controlled.

[0036] The discharge circuit 43 is connected between the pair of switches 41, 42 and the lifting electromagnet 2 through the power supply lines P and N. The discharge circuit 43 is provided to electrically connect the power source 3 and the lifting electromagnet 2. is electrically connected in parallel to

[0037] The discharge circuit 43 includes a discharge circuit switch 45 and a resistor 46. When the pair of switches 41, 42 are in the open state and the discharge circuit switch 45 is in the closed state, the lifting voltage A closed circuit is formed with the magnet 2, and the power stored in the lifting electromagnet 2 is consumed by the resistor 46. That is, the discharge circuit 43 causes the lifting electromagnet 2 to discharge.

[0038] The discharge circuit switch 45 is, for example, an electromagnetic switch or an electromagnetic contactor. The switch 45 is controlled in its open / closed state by the lifting electromagnet control device 1. 45 is in a closed state when the pair of switches 41 and 42 are in an open state and the lifting electromagnet 2 is discharged. This is an attitude.

[0039] The resistor 46 has a resistance value within 10 times the resistance value of the lifting electromagnet 2. The excitation current flowing through the upper electromagnet 2 is not immediately reduced, but is reduced relatively slowly. Therefore, when multiple steel plates are attracted by the lifting electromagnet 2, The excitation current flowing through the lifting electromagnet 2 suddenly drops, causing the multiple steel plates to fall at once. It can be prevented.

[0040] The current detector 44 detects the current flowing through the lifting electromagnet 2. 4 is the lifting electromagnet when the steel plate attracted to the lifting electromagnet 2 falls from the lifting electromagnet 2 The current detector 44 detects the current change caused by the electromagnetic induction generated in the lifting electromagnetic induction coil 2. The data is input to the stone control device 1.

[0041] The output of the current detector 44 is used to control the power supply from the power source 3 to the lifting electromagnet 2. It may also be used when

[0042] The lifting electromagnet control device 1 controls the operation of the electric circuit 4 to control the lifting electromagnet 2. The lifting electromagnet control device 1 controls the drive of the electric circuit 4 by a pair of switches 41 and 4 2, and control the driving of the discharge circuit switch 45.

[0043] Specifically, the lifting electromagnet control device 1 controls the driving of a pair of switches 41 and 42. In this way, the power supply from the power source 3 to the lifting electromagnet 2 is controlled. The device 1 controls the discharge of the lifting electromagnet 2 by controlling the drive of the discharge circuit switch 45. Furthermore, the lifting electromagnet control device 1 performs the following during the discharge of the lifting electromagnet 2 by the discharge circuit 43: Based on the excitation current of the lifting electromagnet 2 detected by the current detector 44, the lifting electromagnet 2 This detects the fall of the steel plate being sucked in.

[0044] In detail, the lifting electromagnet control device 1 includes a current control unit 10, an excitation current detection unit 20, and a steel and a plate drop detection unit 30.

[0045] The current control unit 10 controls the driving of the pair of switches 41 and 42 and the discharge circuit switch 45. The current control unit 10 controls the pair of switches 41 and 42 and the discharge circuit switch 45. The current control unit 10 generates and outputs an operating signal for controlling the opening and closing of a pair of switches 41 and 42. By this, the power supply from the power source 3 to the lifting electromagnet 2 is controlled. When the pair of switches 41 and 42 are in the open state, the discharge circuit switch 45 is in the closed state. The lifting electromagnet 2 is discharged by the discharge circuit 43. The electric circuit 43 is connected to the electric circuit 4 so as to reduce the exciting current flowing through the lifting electromagnet 2. This controls the current flowing through the inverter.

[0046] The excitation current detection unit 20 controls the excitation current flowing through the lifting electromagnet 2 by the current control unit 10. When the excitation current is detected by the current detector 44, the excitation current value is obtained. The current detection unit 20 calculates the unit of the excitation current by using the value of the excitation current obtained from the current detector 44. The amount of change per unit time (differential value of the excitation current) is calculated.

[0047] The steel plate drop detection unit 30 detects the lifting of the steel plate based on the value of the excitation current acquired by the excitation current detection unit 20. The falling of the steel sheet M attracted to the electromagnet 2 is detected. Specifically, the steel sheet falling detection unit 30 is The polarity of the differential value of the excitation current obtained by the excitation current detection unit 20 changes from positive to negative. In this case, it is detected that the steel plate M attracted to the lifting electromagnet 2 is falling. The lower detector 30 detects the lifting electromagnet 2 when the polarity of the differential value of the excitation current changes from negative to positive. It may be possible to detect that the steel plate M being sucked is falling.

[0048] As described above, the steel plate drop detector 30 detects that the steel plate M has fallen from the lifting electromagnet 2. When the alarm is issued, a signal is output to the outside of the lifting electromagnet control device 1 to notify workers, etc. The lifting electromagnet control device 1 may display the following on the screen based on the output signal. etc. may be carried out.

[0049] FIG. 2 shows the flow of the magnetic flux that flows into the lifting electromagnet 2 when the steel plate M that is attracted to the lifting electromagnet 2 falls. 2 is a diagram showing a change in excitation current and a change in magnetic flux. When three steel plates M are attracted to the electromagnet 2 and fall from the electromagnet 2 in order, The changes in excitation current and magnetic flux are shown.

[0050] As shown in FIG. 2, when the steel plate M falls from the lifting electromagnet 2, the excitation current flowing through the lifting electromagnet 2 is The magnetic current increases temporarily. Except for the timing when the steel plate M falls from the lifting electromagnet 2, The excitation current gradually decreases.

[0051] On the other hand, the magnetic flux generated in the lifting electromagnet 2 increases from the timing when the steel plate M falls from the lifting electromagnet 2. In this way, the magnetic field generated in the hoisting electromagnet 2 changes before the magnetic field (see P1 to P3 in Fig. 2). The timing of the change in magnetic flux is not long before the steel plate M falls from the lifting electromagnet 2. Moreover, the change in the magnetic flux generated in the lifting electromagnet 2 is small, This is much more difficult to distinguish than the change in excitation current flowing through 2.

[0052] In this way, it is not the magnetic flux that makes it difficult to determine the fall of the steel plate M, but the excitation current flowing through the lifting electromagnet 2. By using this to determine the fall of the steel plate M, the fall of the steel plate M from the lifting electromagnet 2 can be accurately detected. It can be detected quickly.

[0053] FIG. 3 shows the changes in the excitation current and magnetic flux when the steel plate M falls from the hoisting electromagnet 2, and the FIG. 1 is a diagram showing the relationship between the behavior of the electric circuit 4 and the pair of switches 41 and 42 in the open state. When the discharge circuit switch 45 is in a closed state, the excitation current flowing through the lifting electromagnet 2 is The magnetic current decreases, and the power stored in the lifting electromagnet 2 is consumed by the discharge circuit 43. After the regeneration mode, the excitation current flowing through the lifting electromagnet 2 increases. until the polarity of the differential value of the excitation current changes from positive to negative (until the peak of the excitation current). The period is a peeling mode in which the steel plate M is peeled off from the lifting electromagnet 2. After the peeling mode, the material falls from the lifting electromagnet 2.

[0054] FIG. 4 is a flow chart showing the operation of the lifting electromagnet control device 1 to detect the drop of a steel plate. When the flow shown in FIG. 4 starts (START), first, in step S1, The control device 1 judges whether a drop command is input. In step S1, If it is determined that a command has been input (YES), the process proceeds to step S2, where the current The control unit 10 opens the pair of switches 41 and 42 and turns on the discharge circuit switch 45. Put it in the closed state.

[0055] On the other hand, if it is determined in step S1 that the drop command has not been input (NO), In this case, the judgment of step S1 is performed until a drop command is input to the lifting electromagnet control device 1. Repeat.

[0056] In the next step S3, the excitation current detection unit 20 detects the excitation current detected by the current detector 44. The value of the magnetic current is acquired, and the differential value of the acquired exciting current is calculated. In S4, the steel plate drop detection unit 30 detects whether the polarity of the calculated differential value of the excitation current has changed from positive to negative. Determine whether or not

[0057] In step S4, it is determined that the polarity of the calculated differential value of the excitation current has changed from positive to negative. If the result is YES, in the next step S5, the steel plate drop detection unit 30 detects the lifting voltage It is determined that the steel plate M has fallen from the magnet 2. Then, in step S6, the lifting electromagnet control device After outputting the information that the steel plate M has fallen, the device 1 ends this flow (END).

[0058] On the other hand, in step S4, the polarity of the calculated differential value of the excitation current changes from positive to negative. If it is determined that the excitation current detection unit 2 is not detected (if NO), the process returns to step S3. 0 again acquires the value of the excitation current detected by the current detector 44, and The differential value of the excitation current is calculated.

[0059] The lifting electromagnet control device 1 of this embodiment is a lifting electromagnet that lifts a steel plate M by electromagnetic force. The lifting electromagnet control device 1 controls the electric circuit 4 that drives the lifting electromagnet 2. When the steel plate M is dropped, the exciting current flowing through the lifting electromagnet 2 is decreased. A current control unit 10 controls the current flowing through the electric circuit 4 so as to cause the When the current flowing through the electric circuit 4 is controlled by the and a magnetizing current detection unit based on the magnetizing current detected by the magnetizing current detection unit. A steel plate drop detector detects the drop of the steel plate M lifted by the lifting electromagnet 2. 30 and has.

[0060] When the steel plate M lifted by the lifting electromagnet 2 is dropped, the current control unit 10 This reduces the exciting current flowing through the lifting electromagnet 2. When it falls, an induced current flows in the lifting electromagnet 2 due to the change in magnetic flux, The exciting current flowing through stone 2 increases temporarily. Such a change in the exciting current is the cause of the steel plate M falling. This change in magnetic flux occurs at the same time and is larger than the change in magnetic flux caused by the steel plate M being dropped.

[0061] Therefore, the above-mentioned change in the excitation current is detected by the excitation current detection unit 20. The steel plate drop detector 30 detects the drop of the steel plate based on the excitation current, and the lifting The fall of the steel sheet M against the electromagnet 2 can be detected with high accuracy.

[0062] Moreover, by detecting the change in the excitation current flowing through the lifting electromagnet 2, Since the falling of the steel plate M against the lifting electromagnet device X1 can be detected, the lifting electromagnet device X1 is not affected by the skill of the operator. The fall of the steel plate M can be detected without being affected by the impact.

[0063] Therefore, with the above-mentioned configuration, the lifting electromagnet 2 can be operated without being affected by the skill of the operator. The drop of the lifted steel plate M can be detected with high accuracy.

[0064] In this embodiment, the steel plate drop detection unit 30 detects the amount of change in the excitation current per unit time (excitation current When the polarity of the current (differential value of the current) changes, the steel plate M being lifted by the lifting electromagnet 2 Detects falls of the device.

[0065] In this way, by detecting the change in polarity of the differential value of the excitation current flowing through the hoisting electromagnet 2, Therefore, the change in the excitation current can be detected with high accuracy. The fall of the steel plate M can be detected with high accuracy using the excitation current flowing through the lifting electromagnet 2. .

[0066] In this embodiment, the current control unit 10 is lifted by a lifting electromagnet 2. When the steel plate M is dropped, a discharge current is applied to the electric circuit 4 to reduce the exciting current of the lifting electromagnet 2. An electrical circuit 43 is formed.

[0067] As a result, when the steel plate M lifted by the lifting electromagnet 2 is dropped, The excitation current of the electromagnet 2 can be reduced by the discharge circuit 43. The configuration for reducing the excitation current of stone 2 can be realized with a simple structure.

[0068] (Embodiment 2) FIG. 5 is a diagram showing a lifting electromagnet device X2 equipped with a lifting electromagnet control device 100 according to the second embodiment. 1 is a control circuit diagram showing a schematic configuration of the embodiment. The configuration of the embodiment differs from that of the first embodiment in that it has electric circuits 4a, 4b, and 4c. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof is omitted. This will only be explained.

[0069] As shown in FIG. 5, the lifting electromagnet device X2 is a multiple electric circuit electrically connected in parallel. 4a, 4b, and 4c, and a plurality of electric circuits 4a, 4b, and 4c are supplied with power from a power source 3. The lifting electromagnets 2a, 2b, and 2c are connected to the lifting magnets 2a, 2b, and 2c.

[0070] The configuration of the multiple electric circuits 4a, 4b, and 4c is the same as the configuration of the electric circuit 4 in the first embodiment. In addition, the configuration of the plurality of lifting electromagnets 2a, 2b, and 2c is the same as that of the lifting electromagnet 2 of the first embodiment. Therefore, the electric circuits 4a, 4b, and 4c and the lifting electromagnets 2a, A detailed explanation of the configurations of 2b and 2c will be omitted.

[0071] The lifting electromagnet control device 100 controls the driving of a plurality of electric circuits 4a, 4b, and 4c. Thus, the driving of the plurality of lifting electromagnets 2a, 2b, and 2c is controlled. 100 selectively drives at least one of the multiple electric circuits 4a, 4b, and 4c. It is configured to be able to control.

[0072] Specifically, the lifting electromagnet control device 100 has a lifting electromagnet selection unit 110. The electromagnet selection unit 110 selects a plurality of electromagnets according to a signal input to the lifting electromagnet control device 100. At least one of the electric circuits 4a, 4b, and 4c is selected, and Only when the current control unit 10 is turned on, the signal output from the current control unit 10 is permitted. 00 controls the driving of a selected electric circuit from among the plurality of electric circuits 4a, 4b, and 4c, The driving of the lifting electromagnet driven by the electric circuit can be controlled.

[0073] In addition, the lifting electromagnet control device 100 controls the driving of the multiple electric circuits 4a, 4b, and 4c. This is the same as the drive control of the electric circuit 4 by the lifting electromagnet control device 1 in the first embodiment. Therefore, a detailed description of the lifting electromagnet control device 100 will be omitted.

[0074] With the configuration of this embodiment, power is supplied to each of the multiple lifting electromagnets 2a, 2b, and 2c. Since no connection is required, a compact and low-cost lifting electromagnet device X2 can be obtained. can.

[0075] Moreover, as described above, the lifting electromagnet device X2 has a plurality of lifting electromagnets 2a, 2b, and 2c. When using a lifting electromagnet, the temperature of each lifting electromagnet may vary depending on the frequency of use and the environment. In such a case, the electrical resistance of the multiple lifting electromagnets 2a, 2b, and 2c may become Therefore, even if the same voltage is applied to the multiple lifting electromagnets 2a, 2b, and 2c, the lifting voltage The current flowing through each magnet is different. This causes a current to flow through the multiple lifting electromagnets 2a, 2b, and 2c. Therefore, the magnetic flux that is attracted by the multiple lifting electromagnets 2a, 2b, and 2c also varies. The number of plates M also varies.

[0076] In response to this, the lifting electromagnet control device 100 has a lifting electromagnet selection unit 110 and By having a configuration like the lifting electromagnet control device 1 of the first embodiment, A steel plate M can be dropped from one of the magnets 2a, 2b, and 2c. In addition, the drop of the steel plate M can be detected with high accuracy.

[0077] Specifically, in this embodiment, the excitation current detection unit 20 detects an electric circuit 4a, Among the multiple lifting electromagnets 2a, 2b, and 2c electrically connected in parallel via 4b and 4c The exciting current flowing through one of the lifting electromagnets is detected. The steel plate drop detection unit 30 is an exciting current detection unit. Based on the excitation current detected by 20, the lifting electromagnet is lifted. The falling of the steel plate M that is being lifted is detected.

[0078] As a result, in the plurality of lifting electromagnets 2a, 2b, and 2c, the electrical resistance of each lifting electromagnet is The drop of the steel plate M can be detected with high accuracy according to the variation. The number of steel plates M attracted by the lifting electromagnets 2a, 2b, and 2c can be adjusted with high accuracy. It becomes possible.

[0079] The lifting electromagnet control device 100 controls the driving of two or more electric circuits to The drop of the steel plate M from the lifting electromagnets above is detected based on the excitation current flowing through those lifting electromagnets. The device may be configured to output the

[0080] (Embodiment 3) FIG. 6 is a diagram showing a lifting electromagnet device X3 equipped with a lifting electromagnet control device 200 according to the third embodiment. This embodiment is configured by using a power supply 2 instead of a discharge circuit. 30 controls the excitation current flowing through the lifting electromagnet 2, which is different from the configuration of the first embodiment. In the following, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the configurations that are different from the above will be described.

[0081] As shown in FIG. 6, the lifting electromagnet device X3 includes a lifting electromagnet 2, an electric circuit 240, and a lifting The electromagnet control device 200 is provided. The electric circuit 240 does not have a discharge circuit. Other than that, it is the same as the electric circuit 4 of the first embodiment. The explanation will be omitted.

[0082] The lifting electromagnet control device 200 includes a current control unit 210, an excitation current detection unit 20, and a steel plate dropper. and a lower detection unit 30.

[0083] The current control unit 210 includes a positive excitation thyristor circuit 233 and a negative excitation thyristor circuit 234 of the power supply 230, which will be described later. By controlling the driving of the thyristors T constituting the respective thyristor circuits 234 for The current flowing through the lifting electromagnet 2 is controlled.

[0084] In detail, the current control unit 210 is a thyristor that constitutes the positive excitation thyristor circuit 233. By controlling the drive of T, an exciting current is passed through the hoisting electromagnet 2 to generate a magnetic flux. On the other hand, the current control unit 210 controls the driving of the thyristor T constituting the back excitation thyristor circuit 234. By controlling the current, the excitation current flowing through the lifting electromagnet 2 is reduced. The control unit 210 controls the driving of the thyristor T that constitutes the back excitation thyristor circuit 234. By this, the discharge of the hoisting electromagnet 2 can also be controlled.

[0085] The power source 230 includes an AC power source 231, a circuit breaker 232, and a positive excitation thyristor circuit 233. The positive excitation thyristor circuit 233 is electrically The positive excitation thyristor circuit 233 has three pairs of thyristors T connected in series. Three pairs of thyristors T are electrically connected in parallel, and each pair of thyristors T The midpoint is electrically connected to the AC power source 231. The reverse excitation thyristor circuit has two pairs of thyristors T electrically connected in series. The circuit 234 has two pairs of thyristors T electrically connected in parallel, and each pair of thyristors The midpoint of the thyristor T is connected to the AC power source 231 and the two pairs of thyristors of the positive excitation thyristor circuit 233. A circuit electrically connected to each midpoint of T.

[0086] In the positive excitation thyristor circuit 233, the cathode of the thyristor T is connected to the power supply line P. In the reverse excitation thyristor circuit 234, a thyristor is connected to the power supply line N. The cathode of T is connected.

[0087] As in the present embodiment, instead of a discharge circuit, the excitation voltage of the lifting electromagnet 2 is generated by a power supply 230. That is, the current control unit 210 of the present embodiment may reduce the current by the lifting electromagnet 2. When the steel plate M is dropped, the exciting current of the lifting electromagnet 2 is reduced. In this way, the current supplied to the electric circuit 240 is adjusted. When the lifted steel plate M is dropped, the current supplied to the electric circuit 240 is adjusted. This makes it possible to easily reduce the exciting current of the lifting electromagnet 2. Since the discharge circuit as in the first embodiment is not required, the electric circuit 240 can be made compact. can be done.

[0088] (Modification of the third embodiment) In the above embodiment, the power supply 230 includes a positive excitation thyristor circuit 233 and a negative excitation thyristor circuit 234. However, the power supply configuration is such that the excitation current of the lifting electromagnet 2 is reduced. Other configurations may be used as long as they are capable of reducing the power consumption.

[0089] That is, as shown in FIG. 7, the power supply 330 uses a switching element such as an IGBT. Specifically, the power supply 330 includes an AC power supply 331 and a first switch. The first switching circuit 332 and the second switching circuit 333 .

[0090] The first switching circuit 332 includes a pair of switching elements S The first switching circuit 332 has three pairs of switching elements SW. 3, and the midpoint of each pair of switching elements SW is connected to an AC power source 331. Each switching element SW has a diode in inverse parallel. In the following description, the midpoints of the switching elements SW of each pair are The side of the switching element SW on one side is called the upper arm, and the side of the switching element SW on the other side is called the is called the lower arm.

[0091] The second switching circuit 333 includes a pair of switching elements S The second switching circuit 333 has three pairs of switching elements SW. The midpoint of the two pairs of switching elements SW is connected to the lifting electromagnet 2. It is an electrically connected circuit. Each switching element SW has a diode connected in reverse parallel. In the following description, the switching elements SW of each pair are connected to each other. The other side of the midpoint of each pair of switching elements SW is called the upper arm. It's called the lower arm.

[0092] The first switching circuit 332 and the second switching circuit 333 are electrically connected in parallel. In addition, the first switching circuit 332 and the second switching circuit 333 A smoothing capacitor 334 is electrically connected in parallel.

[0093] The first switching circuit 332 and the second switching circuit 33 having the above-mentioned configuration The lifting electromagnet control device 300 controls the lifting electromagnet control device 30. The power supply control unit 310 includes a current control unit 310, an excitation current detection unit 20, and a steel plate drop detection unit 30. The flow control unit 310 controls the switching of the first switching circuit 332 and the second switching circuit 333. By controlling the driving of the switching element SW, the excitation current flowing through the lifting electromagnet 2 is controlled. .

[0094] In detail, the current control unit 310 controls the first switching circuit 332 and the second switching circuit 333 as follows. It controls the driving of the switching element SW of the switching circuit 333 .

[0095] When power is supplied from the AC power source 331 to the lifting electromagnet 2, the current control unit 310 Among the multiple switching elements SW constituting the switching circuit 332, the upper arm and the lower arm The switching elements SW of the arms are turned on one by one, and the second switching circuit 3 Among the multiple switching elements SW constituting 33, the upper arm and lower arm switching Turn on the element switches one by one. This causes the AC power supply to Current flows from 331 to the lifting electromagnet 2.

[0096] When discharging the lifting electromagnet 2, the current control unit 310 controls the second switching circuit 33 Of the multiple switching elements SW constituting the 3, either the upper arm or the lower arm Turn on one switching element SW. This causes the ON switching element SW Current flows through the diode connected in inverse parallel to the other switching element SW. As shown by the thick line in FIG. 8, a closed circuit is formed with respect to the lifting electromagnet 2. Since the exciting current flowing through magnet 2 can be gradually reduced, the lifting electromagnet 2 can be discharged. can be done.

[0097] The current control unit 310 is a control device for a hoisting electromagnet, similar to the current control unit 10 of the first embodiment. When a drop command is input to the device 300, the excitation current flowing through the lifting electromagnet 2 is reduced. , the switching elements SW of the first switching circuit 332 and the second switching circuit 333 This allows the steel plate M to be dropped from the lifting electromagnet 2.

[0098] As in this modified example, the circuit using the switching element SW also By controlling the flowing excitation current, the drop of the steel plate M against the lifting electromagnet 2 can be controlled. .

[0099] (Other embodiments) The embodiment of the present invention has been described above. The above-mentioned embodiment is for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment and does not deviate from the spirit thereof. The above-described embodiment can be modified appropriately without departing from the scope of the present invention.

[0100] In the first embodiment, the discharge circuit 43 includes a discharge circuit switch 45 and a resistor 46. However, the discharge circuit uses a diode instead of a discharge circuit switch and resistor. By having the discharge circuit include a diode in this manner, the discharge circuit is suspended from the power supply. When power is supplied to the electromagnet, the lifting electric current is supplied while suppressing the flow of current through the discharge circuit. When discharging the magnet, a discharge circuit can be formed. Note that if the discharge circuit has a diode, When the lifting electromagnet is in the lifting position, the lifting electromagnet discharges due to its resistance.

[0101] In the first embodiment, the steel plate drop detection unit 30 of the lifting electromagnet control device 1 is The polarity of the change in the excitation current per unit time (the differential value of the excitation current) However, the steel plate drop detection unit detects the fall of the steel plate M by detecting the flow of the lifting electromagnet 2. The drop of the steel sheet M may be detected by detecting the peak value of the excitation current.

[0102] In the second embodiment, the lifting electromagnet device X2 includes three lifting electromagnets 2a, 2b, and 2c. However, the lifting electromagnet device has two The lifting electromagnet device may have four or more electric circuits. The electromagnet may have four or more electric circuits.

[0103] In the third embodiment, a thyristor is used as an example of a power source for controlling the current flowing through the hoisting electromagnet 2. This section explains circuits using switching elements such as IGBTs and switches. However, the power supply can be any other type of power supply as long as it is capable of controlling the current flowing through the lifting electromagnet. The power supply circuit may have the following configuration. [Industrial Applicability]

[0104] The present invention is applied to a lifting electromagnet device having a lifting electromagnet that lifts a steel plate by electromagnetic force. It is possible. [Explanation of symbols]

[0105] X, X1, X2, X3, X4 Lifting electromagnet device 1, 100, 200, 300 Lifting electromagnet control device 2, 2a, 2b, 2c lifting electromagnet 3, 230, 330 power supply 4, 4a, 4b, 4c, 240 Electrical circuits 10, 210, 310 Current control section 20 Excitation current detection section 30 Steel plate drop detector 41, 42 Switchgear 43 Discharge circuit 44 Current detector 45 Discharge circuit switch 46 resistor 110 Lifting electromagnet selection section 231, 331 AC power supply 232 Circuit Breaker 233 Positive excitation thyristor circuit 234 Thyristor circuit for reverse excitation 332 First switching circuit 333 Second switching circuit P Positive power line N Negative power supply line T Thyristor SW Switching element

Claims

1. A lifting electromagnet that controls the electric circuit that drives the lifting electromagnet that lifts the steel plate by electromagnetic force. A control device for stones, comprising: When the steel plate lifted by the lifting electromagnet is dropped, a current control unit that controls a current flowing through the electric circuit so as to reduce the excitation current flowing; When the current flowing through the electric circuit is controlled by the current control unit, An excitation current detection unit that detects an excitation current flowing through the stone; Based on the excitation current detected by the excitation current detection unit, a steel plate drop detection unit that detects the drop of the steel plate being lifted by the lifting device; having The steel plate drop detection unit detects a change in polarity of the amount of change in the excitation current per unit time. Or, when the peak value of the excitation current is detected, the lifting electromagnet is used to lift the load. detecting a drop of the steel plate being held by the Control device for lifting electromagnets.

2. The lifting electromagnet control device according to claim 1, The current control unit drops the steel plate lifted by the lifting electromagnet. At that time, a discharge circuit is formed in the electric circuit so as to reduce the exciting current of the lifting electromagnet. R, Control device for lifting electromagnets.

3. The lifting electromagnet control device according to claim 1, The current control unit drops the steel plate lifted by the lifting electromagnet. At that time, the current supplied to the electric circuit is adjusted so as to reduce the excitation current of the lifting electromagnet. Adjust, Control device for lifting electromagnets.

4. A lifting electromagnet that controls the electric circuit that drives the lifting electromagnet that lifts the steel plate by electromagnetic force. A control device for stones, comprising: When the steel plate lifted by the lifting electromagnet is dropped, a current control unit that controls a current flowing through the electric circuit so as to reduce the excitation current flowing; When the current flowing through the electric circuit is controlled by the current control unit, An excitation current detection unit that detects an excitation current flowing through the stone; Based on the excitation current detected by the excitation current detection unit, a steel plate drop detection unit that detects the drop of the steel plate being lifted by the lifting device; having The excitation current detection unit is electrically connected in parallel to the power supply via the electric circuit. Detecting an excitation current flowing through one of the multiple lifting electromagnets; The steel plate drop detection unit detects a drop of the steel plate based on the excitation current detected by the excitation current detection unit. and detecting a fall of the steel plate lifted by the one lifting electromagnet. Control device for lifting electromagnets.

5. A lifting electromagnet control device according to any one of claims 1 to 4, The lifting electromagnet; The electrical circuit; Equipped with Hanging electromagnet device.

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