JP2004203503A - Power supply mechanism for lifting magnet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a power supply mechanism for a lifting magnet device capable of switching a power source in a short time without stopping the power supply, surely preventing the short circuit between the power sources, and improving the operation efficiency of the lifting magnet device. <P>SOLUTION: The power supply mechanism 10 for the lifting magnet device for controlling the power to be supplied to a current controller BBC is installed between the current controller BCC for supplying the DC power to a DC electromagnet LM and a plurality of AC power sources ACG for supplying the power to the current controller BCC. The power supply mechanism 10 is provided with a connector 11 for connecting the plurality of the AC power sources ACG to the current controller BCC, and a plurality of DC power sources 12 for converting the AC power to the DC power respectively installed between the connector 11 and the respective AC power sources ACG. The plurality of DC power sources 12 are connected in parallel by the connector 11. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply mechanism of a lifting magnet device. A lifting magnet device is used for a cargo handling operation of adsorbing scraps such as iron scraps and steel frames and transferring the scraps and the steel frames. In this lifting magnet device, since a DC electromagnet is used as the magnet, a control device for controlling supply and stop of DC power to the magnet and a power supply mechanism for controlling DC power supplied to the control device are provided. Have.
The present invention relates to a power supply mechanism of a lifting magnet device for controlling DC power supplied to such a control device.
[0002]
[Prior art]
As shown in FIG. 2, a lifting magnet device mounted on a construction machine such as a crane or a hydraulic excavator generally includes a three-phase AC generator ACG1 (hereinafter, AC generator ACG1) driven by a power source of the construction machine. The AC power supplied from the AC generator ACG1 is rectified into DC power by a rectifier Rec which is a DC power supply, and then supplied to the DC electromagnet LM through the control circuit BCC (for example, , Patent Document 1). In other words, the lifting magnet device mounted on the construction machine can generate a magnetic force on the DC electromagnet LM by supplying power from the AC generator ACG1 mounted on the machine without a fixed power supply such as a factory power supply. There is a feature that the work place is not limited because it is possible.
[0003]
However, since the AC generator ACG1 is driven by a belt directly from an engine or the like of the construction machine or driven by a hydraulic motor using a hydraulic source of the construction machine, the operation of the construction machine itself, for example, movement of a crane arm, etc. When the output of the engine or the like is used, the power required to drive the AC generator ACG1 cannot be secured, and the rotation speed of the AC generator ACG1 may be lower than the specified rotation speed and the voltage may be reduced. In addition, when an abnormality occurs in the belt, the hydraulic motor circuit, or the like, there is a possibility that the rotation speed decreases and the voltage decreases.
[0004]
As described above, as a method for preventing the magnetic force of the DC electromagnet LM from decreasing, a combination of a machine-mounted AC generator ACG1 and a second power supply ACG2 such as a factory power supply or a separately prepared three-phase AC generator is used. I have.
[0005]
As shown in FIG. 3, when the second power supply ACG2 is used together, the three output terminals of the second power supply ACG2 are connected to the wiring U connecting the three output terminals of the AC generator ACG1 and the three input terminals of the rectifier Rec. , V, and W via a power supply connection unit 100, respectively. A power supply switching unit NFB1 is provided between the power supply connection unit 100 and the AC generator ACG1, and a power supply switching unit NFB2 is provided between the power supply connection unit 100 and the second power supply ACG2.
Then, the rotation speed of the AC generator ACG1 becomes lower than the specified rotation speed due to the operation of the construction machine itself, or an abnormality occurs in the belt, the hydraulic motor circuit, etc., and the desired rotation speed does not appear in the AC generator ACG1. Also, if the power supply connected to the rectifier Rec is switched from the AC generator ACG1 to the second power supply ACG2 by the power supply switching units NFB1 and NFB2, power can be supplied from the second power supply ACG2 to the rectifier REC. The operation by the lifting magnet device can be continued.
[Patent Document 1]
Japanese Patent No. 2,602,759
[Problems to be solved by the invention]
However, since both the AC generator ACG1 and the second power supply ACG2 are three-phase AC power supplies, if the power supply switching unit NFB1 and the power supply switching unit NFB2 switch the power supply manually, the AC power The machine ACG1 and the second power supply ACG2 may be connected to the rectifier Rec at the same time. Then, the AC generator ACG1 and the second power supply ACG2 are short-circuited, causing a failure.
Further, in order to prevent a failure due to a human error as described above, it is necessary to switch off the power supply switching unit NFB1 and the power supply switching unit NFB2 after stopping both the AC generator ACG1 and the second power supply ACG2. Since a certain time is required for the switching, the work must be stopped during that time, so that the work efficiency is reduced.
If the power supply switching unit NFB1 and the power supply switching unit NFB2 are switched electrically by using an electromagnetic contactor or the like, it is possible to prevent a short circuit between the AC generator ACG1 and the second power supply ACG2. The configurations of the switching unit NFB1 and the power supply switching unit NFB2 are complicated. In addition, in order to operate the power supply switching unit NFB1 and the power supply switching unit NFB2 in a state where both the AC generator ACG1 and the second power supply ACG2 are stopped, in addition to the AC generator ACG1 and the second power supply ACG2, Another power supply for supplying power to the unit NFB1 and the power supply switching unit NFB2 is required.
[0007]
In view of such circumstances, the present invention can switch power supplies in a short time without stopping power supply, can reliably prevent short-circuits between power supplies, and increase the working efficiency of the lifting magnet device. It is an object of the present invention to provide a power supply mechanism of a lifting magnet device that can perform the power supply.
[0008]
[Means for Solving the Problems]
The power supply mechanism of the lifting magnet device according to claim 1, wherein the power supply mechanism is provided between a current control unit that supplies DC power to the DC electromagnet and a plurality of AC power supplies that supply power to the current control unit. A power supply mechanism of a lifting magnet device for controlling power supplied to a current control unit, wherein the power supply mechanism connects the plurality of AC power supplies to the current control unit, and the connection unit And a plurality of DC power supplies that are provided between each AC power supply and convert AC power into DC power, wherein the plurality of DC power supplies are connected in parallel at the connection part. I do.
According to a second aspect of the present invention, in the power supply mechanism of the lifting magnet device, one of the plurality of AC power supplies is a commercial power supply.
According to a third aspect of the present invention, in the power supply mechanism of the lifting magnet device according to the first aspect, a power selection unit that selects an AC power supply connected to the current control unit is provided between the AC power supply and the DC power supply unit. It is characterized by being provided.
According to a fourth aspect of the present invention, in the power supply mechanism of the lifting magnet device according to the third aspect, the power supply selection unit includes a circuit breaker that cuts off between the AC power supply and the DC power supply unit. And
[0009]
According to the first aspect of the present invention, the AC power supplied from the plurality of AC power supplies is changed to DC power by the DC power supply section and then supplied to the connection section, and the DC power supply sections are connected in parallel. Have been. For this reason, even if the voltage of one AC power supply among the plurality of AC power supplies decreases, the insufficient power is instantaneously supplied from the other power supply, so that the magnetic force of the DC electromagnet is reliably prevented from being reduced. be able to. Therefore, the work by the lifting magnet device can be continued, and the work efficiency can be increased. In addition, since the DC power is converted into DC power by each DC power supply unit and both currents are adjusted, short-circuiting between the AC power supplies can be prevented. In addition, since the protection mechanism for preventing a short circuit is only the DC power supply unit, the structure of the power supply mechanism can be simplified.
According to the second aspect of the invention, even if the voltages generated by all the other AC power supplies are lower than the predetermined voltage, the insufficient power can be reliably compensated for by the stable commercial power supply. The working efficiency of the lifting magnet device can be further increased.
According to the third aspect of the present invention, it is possible to select only the most suitable AC power supply from the plurality of AC power supplies and connect the selected AC power supply to the current control unit, thereby preventing power consumption of other AC power supplies. Alternatively, if the other AC power supply is a generator, its operation can be stopped. For example, if another AC power supply is a generator mounted on a construction machine or the like, by stopping the generator, it is possible to prevent a decrease in the operating capacity of an engine of the construction machine or the like and a deterioration in fuel efficiency.
According to the fourth aspect of the present invention, if the connection between the AC power supply and the DC power supply unit is cut off by the circuit breaker, the AC power supply connected to the current control unit can be selected. Therefore, if the newly connected AC power supply is connected to the current control unit and then the connection between the connected AC power supply and the DC power supply unit is cut off, the supply of power to the current control unit is stopped. Instead, it is possible to switch the AC power supply connected to the current control unit. Therefore, when switching the AC power supply, it is not necessary to stop the work by the lifting magnet device, so that it is possible to prevent a decrease in work efficiency, and it is only necessary to turn ON / OFF the circuit breaker. Can be done in time.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic block diagram of a power supply mechanism 10 of the present embodiment. In FIG. 1, reference numeral ACG1 indicates an AC power supply such as a three-phase AC generator driven by an engine of a construction machine equipped with a lifting magnet device, and reference numeral ACG2 is provided separately from a commercial power supply and a construction machine. This shows an AC power supply such as a three-phase AC generator.
[0011]
When the construction machine is provided with a three-phase AC generator to be used as a backup power supply in the main body, the backup power supply may be the AC power supply ACG2.
Furthermore, if the lifting magnet device is installed in a factory or the like, both AC power supplies ACG1 and ACG2 may be used as commercial power supplies, or the main AC power supply ACG1 may be used as commercial power supply and used when power failure occurs. The AC generator used as a backup power supply or the like may be the AC power supply ACG2.
Furthermore, the AC power supplies ACG1 and ACG2 need not be three-phase AC power supplies, but may be household AC power supplies, single-phase AC power supplies, two-phase AC power supplies, six-phase AC power supplies, or the like.
In other words, the power supply mechanism 10 of the present invention can connect one lifting magnet device to a plurality of AC power supplies at the same time regardless of the type of AC power supply. The feature is that the configuration is such that it is possible to surely prevent the operation from being performed.
[0012]
In FIG. 1, reference numeral LM indicates a DC electromagnet of the lifting magnet device. Reference numeral BCC indicates a current control unit that supplies DC power to the DC electromagnet LM. This current control unit BCC is a bridge control circuit in which diodes D1 to D4 are connected in parallel to four power transistors Tr1 to Tr4, and has substantially the same function and configuration as the bridge circuit disclosed in Japanese Patent No. 2602759. (See FIG. 2). This current control unit BCC has two input terminals A1 and A2, and controls the generation of magnetic force in the DC electromagnet LM by controlling the DC power supplied from the two input terminals A1 and A2. I have.
[0013]
A three-phase AC power supply ACG1, ACG2 is connected to two input terminals A1, A2 of the current control unit BCC via a connection unit 11 of the power supply mechanism 10. A DC power supply unit 12 that converts AC power into DC power is provided between the connection unit 11 of the power supply mechanism 10 and the three-phase AC power supplies ACG1 and ACG2. Three output terminals of three-phase AC power supplies ACG1 and ACG2 are connected to each DC power supply unit 12, respectively. The DC power supply unit 12 rectifies the AC power supplied from the three-phase AC power supplies ACG1 and ACG2 and outputs two DC powers. It is output from the terminal.
The two output terminals of each DC power supply unit 12 are connected in parallel to the current control unit BCC by the connection unit 11.
[0014]
For this reason, even if the voltage of one three-phase AC power supply ACG1 of the two three-phase AC power supplies ACG1 and ACG2 drops, insufficient power is instantaneously supplied from the three-phase AC power supply ACG2. Can be reliably prevented from being reduced.
Therefore, during the operation of the lifting magnet device, even if the voltage of the three-phase AC power supply ACG1 decreases due to fluctuations in the engine rotation speed of the construction machine or the malfunction of the three-phase AC power supply ACG1 itself, the operation using the lifting magnet device can be performed. It can be continued, and work efficiency can be increased.
In particular, if a commercial power supply is used for the three-phase AC power supply ACG2, even if the voltage generated by the three-phase AC power supply ACG1 falls below a predetermined voltage, the insufficient power can be reliably reduced by the stable commercial power supply. Since the compensation can be made, the working efficiency by the lifting magnet device can be further increased.
[0015]
Further, since the respective DC power supply units 12 are connected in parallel by the connection unit 11, that is, the AC power is converted into the DC power, and then the currents supplied from the two three-phase AC power supplies ACG1 and ACG2 are matched. Short-circuit between the two three-phase AC power supplies ACG1 and ACG2 can be prevented. Moreover, if the DC power supply unit 12 is provided between the three-phase AC power supplies ACG1 and ACG2 and the current control unit BCC, a short circuit can be prevented, so that the structure of the power supply mechanism 10 can be simplified.
[0016]
Further, between each DC power supply unit 12 and two three-phase AC power supplies ACG1 and ACG2, power supply selection units 15a and 15b are provided, respectively. The power supply selectors 15a and 15b include, for example, a circuit breaker 16 that disconnects and connects the three-phase AC power supplies ACG1 and ACG2 to each of the DC power supply sections 12.
For this reason, if both of the three-phase AC power supplies ACG1 and ACG2 are connected to the current control unit BCC by the power supply selection units 15a and 15b, power can be simultaneously supplied from both to the current control unit BCC. If only one of the power supplies ACG1 and ACG2 is connected to the current control unit BCC, power can be supplied to the current control unit BCC from only one of the three-phase AC power supplies.
Therefore, only the most suitable three-phase AC power supply among the three-phase AC power supplies ACG1 and ACG2 can be selected and connected to the current control unit BCC, so that the power consumption of the other three-phase AC power supplies can be prevented. If the other AC power supply is a generator, the operation can be stopped. For example, if another AC power supply is a generator mounted on a construction machine or the like, by stopping the generator, it is possible to prevent a decrease in the operating capacity of an engine of the construction machine or the like and a deterioration in fuel efficiency.
[0018]
Then, if the connection between the three-phase AC power supplies ACG1 and ACG2 and each DC power supply unit 12 is cut off by the circuit breaker 16, the three-phase AC power supply connected to the current control unit BCC can be selected.
Therefore, if the newly connected AC power supply is connected to the current control unit BCC, and then the connection between the connected AC power supply and the current control unit BCC is cut off, power supply to the current control unit BCC will be performed. The AC power supply connected to the current control unit BCC can be switched without stopping.
Therefore, when switching between the three-phase AC power supplies ACG1 and ACG2, it is not necessary to stop the work by the lifting magnet device, so that it is possible to prevent a decrease in work efficiency. In addition, the three-phase AC power supplies ACG1 and ACG2 connected to the current control unit BCC can be switched simply by turning ON / OFF the circuit breaker 16, so that the switching can be performed in a short time.
[0019]
In the power selection units 15a and 15b, the mechanism for switching the connection between the three-phase AC power supplies ACG1 and ACG2 and each DC power supply unit 12 is not limited to the circuit breaker 16, but the three-phase power supply units 15a and 15b An electromagnetic contactor operated by AC power supplies ACG1 and ACG2 may be used, and there is no particular limitation.
Furthermore, the number of AC power supplies connected to the connection unit 11 is not limited to two, and three or more AC power supplies may be connected.
[0020]
【The invention's effect】
According to the first aspect of the present invention, since it is possible to reliably prevent the magnetic force of the DC electromagnet from being reduced, it is possible to further increase the working efficiency of the lifting magnet device. Further, short-circuiting between AC power supplies can be prevented, and the structure of the power supply mechanism can be simplified.
According to the second aspect of the invention, the working efficiency of the lifting magnet device can be further increased.
According to the third aspect of the present invention, it is possible to prevent power consumption of another AC power supply, and to stop the operation of another AC power supply if the other AC power supply is a generator.
According to the fourth aspect of the present invention, it is possible to prevent a decrease in work efficiency and to perform switching in a short time.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a power supply mechanism 10 of the present embodiment.
FIG. 2 is a schematic block diagram of a power supply mechanism of a conventional lifting magnet device.
FIG. 3 is a schematic block diagram of a power supply mechanism when two AC power supplies ACG are connected.
[Explanation of symbols]
Reference Signs List 10 Power supply mechanism 11 Connection unit 12 DC power supply unit 15a Power supply selection unit 15b Power supply selection unit 16 Circuit breaker BCC Current control unit LM DC electromagnet ACG Three-phase AC power supply

Claims (4)

A lifting magnet provided between a current control unit that supplies DC power to the DC electromagnet and a plurality of AC power supplies that supply power to the current control unit, for controlling power supplied to the current control unit A power supply mechanism of the device,
The power supply mechanism is
A connection unit that connects the plurality of AC power supplies to the current control unit;
A plurality of DC power supply units that are provided between the connection unit and each AC power supply and convert AC power into DC power,
The power supply mechanism for a lifting magnet device, wherein the plurality of DC power supply units are connected in parallel at the connection unit. The power supply mechanism according to claim 1, wherein one of the plurality of AC power supplies is a commercial power supply. 2. A power supply mechanism for a lifting magnet device according to claim 1, further comprising a power supply selector for selecting an AC power supply to be connected to the current controller, between the AC power supply and the DC power supply. . The power supply selector,
4. The power supply mechanism for a lifting magnet device according to claim 3, further comprising a circuit breaker for cutting off between the AC power supply and the DC power supply unit.

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