JP5679145B2 - Current measuring device - Google Patents

Description

  The present invention relates to a clamp-type current measuring device including a core and a pair of sensors each having a winding formed on the core.

  As this type of clamp-type current measuring device, a current measuring device disclosed by the applicant in the following patent document is known. This current measuring device includes a pair of sensors (a fixed sensor and a movable sensor) each formed in a substantially arc shape. In this case, the fixed side sensor and the movable side sensor are each configured to include a core formed in a substantially arc shape and a winding formed in the core. In addition, the movable side sensor is rotatably disposed in a main body unit formed integrally with the fixed side sensor, and is always urged in a direction to join the fixed side sensor by a spring disposed in the main body unit. Has been. In addition, when the lever portion disposed on the movable side sensor is pushed, the movable side sensor rotates against the urging force of the spring and moves away from the fixed side sensor so that the pushing force on the lever portion does not move. When released, it is rotated in the direction of the fixed sensor by the biasing force of the spring and joined to the fixed sensor.

  In this current measuring device, when a current signal flows through the measurement object in a state where the pair of sensors surround the measurement object (measurement lead) and are joined together, a voltage proportional to the current value of the current signal is generated. , Generated between both ends of each winding connected in series. For this reason, for example, the measurement unit disposed in the main body detects the voltage value of this voltage generated in each winding and calculates the current value of the current signal flowing through the measurement object based on the detected voltage value. (taking measurement.

  On the other hand, in this type of clamp-type current measuring device, when a pair of sensors are not securely joined, a voltage lower than the correct voltage corresponding to the current value of the current signal flowing through the measurement object is applied to both ends of each winding. Since it occurs in the meantime, an error may occur in the measurement result of the current signal flowing through the measurement object. For this reason, in the current measuring device disclosed in the above publication, a bonding state inspection coil, a signal supply unit that supplies an inspection signal to the bonding state inspection coil, and a notification unit that notifies a bonding state of the pair of sensors, By adopting a configuration, it is possible to accurately measure by adopting a configuration for accurately reporting the joining state and preventing measurement in a state where the pair of sensors are not normally joined.

JP 2009-69089 A (page 4-7, FIG. 1)

  However, in the clamp-type current measuring device described above, by adopting the above-described configuration including a bonding state inspection coil or the like, it is possible to prevent measurement in a state where the pair of sensors are not normally bonded, Accurate measurement is possible. On the other hand, this current measuring device has a problem that the structure of the sensor becomes complicated by that amount because one of the pair of sensors must be provided with a bonding state inspection coil. Improvement of the point is desired.

  The present invention has been made in view of such a problem to be improved, and mainly provides a current measuring device capable of accurately measuring a current flowing through a measurement object without using a bonding state inspection coil. Objective.

In order to achieve the above object, the current measuring device according to claim 1 is characterized in that one of a pair of cores configured as a whole and one of the cores in a state where one end of each other and the other end of each other are joined. One sensor provided with one winding formed on the core of the other, and the other sensor of the other core of the pair of cores and the other winding formed on the other core And the other sensor in which the pair of cores are configured in an annular shape in a clamped state where the sensor is joined to and separated from the one sensor, and a biasing force for biasing the sensors in the joining direction. Each winding due to a current flowing through a measurement object surrounded by the pair of cores configured in a ring shape in a state where the members and the sensors are joined by the biasing member A clamp-type current measuring device including a measuring unit that measures a current value of the current based on a detection signal generated, wherein the one ends of the cores have the same polarity and the other ends are the same. An excitation unit for supplying an excitation signal as a pole to each of the windings is provided.

Further, the current measuring device according to claim 2 is formed on one of the pair of cores configured in a ring shape as a whole in a state in which one end of each other and the other end of each other are joined to each other. One sensor provided with one winding formed, the other core of the pair of cores and the other winding formed on the other core, and joining and separating from the one sensor The other sensor in which the pair of cores are configured in an annular shape in a clamped state where the sensor is joined to the one sensor, a biasing member that biases each sensor in the joining direction, Detection that occurs in each of the windings due to a current that flows through the measurement object surrounded by the pair of cores configured in an annular shape in a state where each sensor is joined by the biasing member A clamp-type current measuring device including a measuring unit that measures a current value of the current based on the number, wherein the one ends of the cores have different polarities and the other ends have different polarities. An excitation unit that supplies one of the excitation signals selected from the excitation signal and the excitation signal having the same polarity at one end of each core and the other end as the same polarity to each winding. It has.

According to a third aspect of the present invention, in the current measuring device according to the first or second aspect , the demagnetizing magnetic field for demagnetizing the residual magnetization remaining in the cores is generated in the windings. Is provided with a degaussing section for supplying the demagnetization signal to the windings.

According to the current measuring device 請 Motomeko 1, each winding excitation signal one ends of the pair of cores is the same polarity, and the other ends are energized each winding formed on each core so that the same poles By providing the excitation unit that supplies the wire, a repulsive force can be applied between the two sensors by operating the excitation unit. Therefore, according to this current measuring device, the urging force of the urging member that joins the two sensors can be weakened by the repulsive force acting between the two sensors. Can be easily transferred to.

According to the current measuring device of claim 2 , the excitation signal in which one end of the pair of cores has different polarities and the other end has different polarities, the one end of each core has the same polarity, and the other By providing an excitation unit that supplies one of the excitation signals selected from among the excitation signals having the same polarity to the ends to each winding, an attraction force is generated between the two sensors by operating the excitation unit. Both sensors can be joined better than the configuration in which both sensors are joined only by the urging force of the urging member. Further, according to this current measuring device, the repulsive force can be applied between the two sensors by operating the excitation unit, whereby the urging force of the urging member can be weakened by this repulsive force. It is also possible to easily shift the sensor from the clamped state to the unclamped state.

Further, according to the current measuring device of claim 3 , since the demagnetizing section is provided, it is possible to demagnetize residual magnetization that may remain in each core by supplying an excitation signal to each winding. It is possible to reliably prevent a decrease in current measurement accuracy caused by residual magnetization caused by the supply of the excitation signal.

It is a front view of the electric current measurement apparatus 1 when the clamp part 2 is a clamped state. It is a front view of the electric current measurement apparatus 1 when the clamp part 2 is a non-clamp state. 1 is a configuration diagram showing a circuit configuration of a current measuring device 1. FIG. It is a block diagram for demonstrating operation | movement of the electric current measurement apparatus 1 which produces | generates attraction | suction force between both the sensors 11 and 12 of FIG. It is a block diagram for demonstrating operation | movement of the electric current measurement apparatus 1 which produces a repulsive force between both the sensors 11 and 12 of FIG. It is a block diagram for demonstrating operation | movement of the electric current measurement apparatus 1 which demagnetizes the cores 23a and 23b of FIG.

  Hereinafter, embodiments of a current measuring device will be described with reference to the accompanying drawings.

  First, the configuration of the current measuring device 1 will be described with reference to the drawings.

  A current measuring device 1 shown in FIG. 1 includes a clamp portion 2 and a main body portion 3 and is configured to be able to measure a current I flowing in a conducting wire 100 as a measurement object without contact.

  As shown in FIG. 1, the clamp unit 2 includes a fixed side sensor 11 and a movable side sensor 12 (a pair of sensors 11 and 12) formed in a substantially semicircular shape in plan view, as an example. In addition, as shown in FIGS. 1 and 2, the clamp unit 2 is configured such that the fixed side sensor 11 and the movable side sensor 12 can be joined to and separated from each other by an opening / closing operation on a lever 21 c described later.

  As shown in FIG. 1, the fixed side sensor (one sensor) 11 includes a sensor case 21 a and a coil portion 22 a each formed in a substantially semicircular shape in plan view. The sensor case 21 a is integrally formed with the main body case 3 a constituting the main body portion 3. The coil portion 22a includes a core (one core) 23a formed in a substantially semicircular shape in plan view and a winding (one winding) 24a wound around the core 23a (see FIG. 3 for both). And disposed in the sensor case 21a.

  As shown in FIG. 1, the movable side sensor (the other sensor) 12 is not distinguished from the sensor case 21 b and the coil part 22 b (hereinafter, the coil part 22 a of the fixed side sensor 11) formed in a substantially semicircular shape in plan view. (Sometimes also referred to as “coil portion 22”). The sensor case 21b has a base end portion housed in the main body case 3a, and is attached to the main body case 3a so as to be rotatable around a pin 3b inserted through the base end portion. The sensor case 21b is joined to the sensor case 21a by a spring 3c as an example of an urging member disposed in the main body case 3a (both sensors 11 and 12 are in a clamped state (joined state)). It is always urged to rotate in the direction of arrow A shown in FIG.

  The sensor case 21b is separated from the sensor case 21a when the lever 21c formed integrally with the sensor case 21b is pushed into the main body case 3a in the direction of arrow B shown in FIG. 2 (both sensors 11, 12). Is configured to rotate in the direction of being in an unclamped state. The coil portion 22b includes a core (the other core) 23b and a winding (the other winding) 24b (both of which are shown in FIG. 3) formed in a substantially semicircular shape in plan view, and is disposed in the sensor case 21b. ing.

  In the clamp portion 2 configured as described above, as shown in FIG. 1, the pair of sensors 11 and 12 are joined, that is, the distal end portion 11a of the fixed sensor 11 and the distal end portion 12a of the movable sensor 12 (specifically, Are joined together, and the base end portion 11b of the fixed sensor 11 and the base end portion 12b of the movable sensor 12 (specifically, the base portions of the coil portions 22a and 22b). In a state where the end portions are joined together, the movable sensor 12 resists the biasing force of the spring 3c by performing an operation (pushing operation) of pushing the lever 21c in the direction of arrow B shown in FIG. It rotates in the direction away from the fixed side sensor 11, and shifts to the unclamped state shown in FIG. In the unclamped state, the pair of sensors 11 and 12 are separated from each other, that is, the distal end portion 11a of the fixed sensor 11 and the distal end portion 12a of the movable sensor 12 (specifically, the distal ends of the coil portions 22a and 22b). Since the base end portion 11b of the fixed side sensor 11 and the base end portion 12b of the movable side sensor 12 (specifically, the base end portions of the coil portions 22a and 22b) are apart from each other, As shown in FIG. 2, it is possible to introduce the conductive wire 100 between the pair of sensors 11 and 12 from the outside through a gap between the tip portions 11 a and 12 a as indicated by a one-dot chain line.

  In addition, in the unclamped state shown in FIG. 2, by performing an operation of releasing the pushing of the lever 21c in the direction of the arrow B, the movable sensor 12 is moved in the direction of the fixed sensor 11 by the biasing force of the spring 3c ( 1, the lever 21c is protruded from the main body case 3a, and as shown in FIG. In this clamped state, the clamp part 2 is wound with the windings 24a and 24b (as described later) due to the current I flowing through the conducting wire 100 introduced between the pair of sensors 11 and 12 (clamped by the clamp part 2). It is possible to output an induced voltage (voltage corresponding to the current value of the current I) V1 (see FIG. 3) as a detection signal generated in the windings 24a and 24b connected in series.

  In addition to the main body case 3a, the pin 3b, and the spring 3c, the main body 3 includes two on / off switches (hereinafter also simply referred to as “switches”) 31, 32 and a switching unit 33, as shown in FIG. A measurement unit 34, a processing unit 35, an operation unit 36, an excitation unit 37, a demagnetization unit 38, a storage unit 39, and an output unit 40. In this case, the switches 31, 32, the switching unit 33, the measurement unit 34, the processing unit 35, the excitation unit 37, the demagnetization unit 38, and the storage unit 39 are disposed in the main body case 3a, and the operation unit 36 and the output unit 40 are illustrated in FIG. As shown to 1 and 2, it is arrange | positioned on the surface of the main body case 3a.

  Specifically, the switch 31 has, at one end (one contact), a winding end on the distal end side returned to the proximal end side of the coil portion 22a in the winding 24a (hereinafter referred to as “the distal end side of the winding 24a”). Is connected to the other end (the other contact), and the winding end (hereinafter referred to as “winding”) of the winding 24b on the distal end side returned to the base end side of the coil portion 22b. 24b ”is also connected. One end (one contact) of the switch 32 is connected to one end of the switch 31, and the other end (other contact) is connected to a minus terminal of an excitation power source 37 a (described later) constituting the excitation unit 37. Each switch 31, 32 is controlled to be on / off by the processing unit 35.

  The switching unit 33 includes a plurality of change-over switches (not shown), and equivalently functions as two single-circuit three-contact change-over switches SW1 and SW2 as shown in FIG. In this case, the changeover switch SW1 is selected from the positive terminal of the excitation power source 37a, one input terminal of the pair of input terminals of the measurement unit 34, and one output terminal of the pair of output terminals of the demagnetization unit 38. Any one selected is connected to the winding end on the proximal end side of the coil portion 22a in the winding 24a (hereinafter also referred to as "winding end on the proximal end side of the winding 24a"). The changeover switch SW2 winds an arbitrary one selected from an invert circuit 37b, which will be described later, constituting the excitation unit 37, the other input terminal of the measurement unit 34, and the other output terminal of the demagnetization unit 38. It is connected to the winding end on the base end side of the coil portion 22b in 24b (hereinafter also referred to as “winding end on the base end side of the winding 24b”). In the switching unit 33, the switching state of the selector switches SW <b> 1 and SW <b> 2 is controlled by the processing unit 35.

  The measurement unit 34 includes a pair of input terminals (not shown). One input terminal of the pair of input terminals is connected to the switch SW1 of the switching unit 33, and the other input terminal is a switch of the switching unit 33. By being connected to the switch SW2, the windings 24a and 24b of the clamp unit 2 can be connected via the switching unit 33. Further, the measuring unit 34 is connected to the windings 24a and 24b of the clamp unit 2 via the switching unit 33 based on the induced voltage V1 (AC voltage) generated in the windings 24a and 24b. The current value Di of the current I flowing in the conducting wire 100 clamped by 2 is measured and output to the processing unit 35.

  The processing unit 35 includes a CPU (not shown) and is configured to join the coil units 22 a and 22 b of the clamp unit 2 based on the operation content of the operation unit 36, and the coil units of the clamp unit 2. Separation processing for separating 22a and 22b, measurement processing for measuring the current value Di of the current I flowing through the conducting wire 100, and degaussing processing for demagnetizing the cores 23a and 23b of the coil portions 22a and 22b are performed. The processing unit 35 also executes control for the switches 31 and 32, the switching unit 33, the excitation unit 37, and the demagnetization unit 38.

  As shown in FIGS. 1 and 2, the operation unit 36 includes, for example, a power switch 36a, a clamp close switch (hereinafter also referred to as “closed switch”) 36b, and a clamp open switch (hereinafter also referred to as “open switch”) 36c. A measurement start switch (hereinafter also referred to as “measurement switch”) 36d and a demagnetization switch 36e, and these switches 36a to 36e are arranged on the surface of the main body case 3a. In this case, the power switch 36a is composed of, for example, an on / off switch, and from a main power supply (not shown) disposed in the main body case 3a to each component disposed in the main body case 3a. Turns on or off the supply of the operating voltage. Further, when the close switch 36b, the open switch 36c, the measurement switch 36d, and the demagnetization switch 36e are operated, the operation unit 36 outputs an operation signal Sop corresponding to the operation content to the processing unit 35.

  As shown in FIG. 3, the excitation unit 37 includes an excitation power source 37a and an invert circuit 37b. The excitation power supply 37a receives the supply of the operating voltage from the main power supply described above, generates a constant excitation voltage (DC voltage) V2, and outputs it from a pair of output terminals (plus terminal and minus terminal). The excitation unit 37 outputs an excitation voltage (DC voltage) V2 as an excitation signal with a constant polarity to the winding 24a of the coil unit 22a, and to the winding 24b of the coil unit 22b. Outputs an excitation voltage (DC voltage) V2 set to a desired polarity in the invert circuit 37b as an excitation signal. The generation and output of the excitation voltage V2 by the excitation power supply 37a is controlled by the processing unit 35.

  As shown in FIG. 3, the invert circuit 37b includes four on / off switches (hereinafter also simply referred to as “switches”) SW3, SW4, SW5, and SW6 configured as a bridge circuit, for example. In this case, each end (one contact) of the switches SW3 and SW5 is connected to each other and to the minus terminal of the excitation power source 37a. The other end (other contact) of the switch SW3 is connected to one end (one contact) of the switch SW4 and to the other end of the switch 31. The other end (other contact) of the switch SW5 is connected to one end (one contact) of the switch SW6 and to the changeover switch SW2 of the changeover unit 33. The other ends (other contacts) of the switches SW4 and SW6 are connected to each other and to the plus terminal of the excitation power source 37a.

  In the invert circuit 37b configured as described above, when the processing unit 35 controls the on / off states of the switches SW3, SW4, SW5, and SW6, the switches SW3 and SW6 are turned on, and the switches SW4 and SW5 are turned on. Repulsive connection in which the positive terminal of the excitation power source 37a is connected to the winding end on the proximal end side of the winding 24b and the minus terminal of the excitation power supply 37a is connected to the winding end on the distal end side of the winding 24b. The switches SW4 and SW5 are turned on, the switches SW3 and SW6 are turned off, the negative terminal of the excitation power source 37a is connected to the winding end on the proximal end side of the winding 24b, and the tip end of the winding 24b is connected. Suction connection state in which the positive terminal of the excitation power source 37a is connected to the winding end on the side (a connection state in which an excitation voltage V2 having a reverse polarity is supplied to the winding 24b with respect to the repulsion connection state , And all the switches SW3~SW6 shifts to any one connected state among the disconnected connection state turned off.

  The demagnetizing unit 38 receives the operating voltage from the main power source and demagnetizes the demagnetizing signal (for example, the amplitude gradually decreases) as a demagnetizing signal for demagnetizing the cores 23a and 23b of the coil units 22a and 22b. The AC voltage V3 becomes zero and is output from a pair of output terminals (not shown). The generation and output of the demagnetizing voltage V3 by the demagnetizing unit 38 is controlled by the processing unit 35.

  The storage unit 39 includes a memory such as a ROM or a RAM, and stores an operation program for the processing unit 35 in advance. The output unit 40 is configured by a display device such as an LCD (Liquid Crystal Display) as an example, and displays the current value Di of the measured current I of the conducting wire 100 on the screen by the processing unit 35. As shown in FIGS. 1 and 2, the output unit 40 is disposed such that the screen is located on the same surface as the surface of the main body case 3 a on which the operation unit 36 is disposed.

  Next, the operation of the current measuring device 1 will be described with reference to the drawings together with the procedure for measuring the current value Di of the current I flowing through the conducting wire 100 using the current measuring device 1.

  When measuring the current value Di of the current I flowing through the conducting wire 100 using the current measuring device 1, first, the conducting wire 100 is clamped by the clamp portion 2. Specifically, the lever 21c is pushed into the main body case 3a and the movable sensor 12 is rotated against the urging force of the spring 3c in the direction opposite to the arrow A direction shown in FIG. As shown, the distal end portions 11a, 12a and the proximal end portions 11b, 12b of the sensors 11, 12 are separated from each other.

  Next, as shown in FIG. 2, the lead wire 100 is introduced into the sensors 11, 12 from the separated tip end portions 11 a, 12 a side, and then the lever 21 c is released. Thereby, the movable side sensor 12 is rotated to the fixed side sensor 11 side by the urging force of the spring 3c, and the distal end portions 11a and 12a and the proximal end portions 11b and 12b of the sensors 11 and 12 are joined to each other. Thereby, the clamp part 2 transfers to a clamped state. Thereby, as shown in FIG. 1, the conducting wire 100 is clamped by the clamp part 2 (enclosed by both the sensors 11 and 12).

  Subsequently, the power switch 36a of the operation unit 36 is operated to start supplying the operating voltage to each component disposed in the main body case 3a with respect to the main power source in the main body case 3a. Next, the closing switch 36b of the operation unit 36 is operated. Thereby, the operation unit 36 outputs an operation signal Sop corresponding to the closing switch 36b to the processing unit 35. When the operation signal Sop is input, the processing unit 35 performs a joining process for joining the coil units 22a and 22b of the clamp unit 2.

  In this joining process, the processing unit 35 first controls the switches 31 and 32 to shift the switch 31 to the OFF state and shift the switch 32 to the ON state as shown in FIG. In addition, the processing unit 35 executes control on the switching unit 33 to switch the switching unit 33 between the winding end on the proximal end side of the winding 24a and the plus terminal of the excitation power source 37a as shown in FIG. In addition to the connection via the switch SW1, the winding end on the base end side of the winding 24b and the invert circuit 37b are connected via the changeover switch SW2 of the changeover unit 33. Further, the processing unit 35 executes control on the invert circuit 37b, thereby turning the invert circuit 37b into a suction connection state in which the switches SW4 and SW5 are turned on and the switches SW3 and SW6 are turned off as shown in FIG. To migrate.

  As a result, the winding end on the proximal end side of the winding 24a is connected to the plus terminal of the excitation power supply 37a, and the winding end on the distal end side of the winding 24a is connected to the minus terminal of the excitation power supply 37a. The winding end on the proximal end side of the wire 24b is connected to the minus terminal of the excitation power source 37a, and the winding end on the distal end side of the winding 24b is connected to the plus terminal of the excitation power source 37a.

  Next, the processing unit 35 executes control on the excitation power source 37a to start generation and output of the excitation voltage V2 by the excitation power source 37a. As a result, as shown in FIG. 4, the excitation voltage V2 is supplied to the winding ends on the distal ends and the winding ends on the proximal ends of the windings 24a and 24b constituting the coils 22a and 22b. Each coil part 22a, 22b begins to function as an electromagnet. In this case, the exciting voltage V2 is supplied with the polarity shown in FIG. 4 to the winding ends on the distal ends and the winding ends on the base ends of the windings 24a and 24b. The winding directions of the windings 24a and 24b are defined to be the same with respect to the cores 23a and 23b serving as the annular cores. As a result, current flows in the same direction in each of the windings 24a and 24b, and as a result, an N pole is generated on the distal end side (one end of the core 23a) of the coil portion 22a and the proximal end side. An S pole is generated at (the other end of the core 23a), an S pole is generated at the distal end side (one end of the core 23b) of the coil portion 22b, and an N pole is formed at the proximal end side (the other end of the core 23b). A pole is generated. For this reason, one end of the cores 23a and 23b has different polarities and the other ends also have different polarities. As a result, an attractive force begins to act between the coil portions 22a and 22b.

  Therefore, the movable side sensor 12 that is already joined to the fixed side sensor 11 by the urging force of the spring 3c is further pressed against the fixed side sensor 11 side by the above suction force. The portions 11a and 12a and the base end portions 11b and 12b are bonded to each other more satisfactorily. In addition, since the constant excitation voltage V2 is supplied to the windings 24a and 24b, the generated attractive force is always constant. For this reason, by this suction force, the front end portions 11a and 12a and the base end portions 11b and 12b of both the sensors 11 and 12 are always in a constant joined state in any joining process.

  The processing unit 35 executes control on the excitation power source 37a after a predetermined time (for example, about several seconds) has elapsed after the generation and output of the excitation voltage V2 by the excitation power source 37a, and the excitation power source 37a performs the control. The generation and output of the excitation voltage V2 are terminated. Thereby, a joining process is completed. Note that, when the joining process is completed, no suction force is generated between the two coil portions 22a and 22b. However, the two sensors 11 and 12 once joined in a good state are then subjected to the biasing force of the spring 3c. State is maintained.

  Subsequently, the measurement switch 36d of the operation unit 36 is operated. Thereby, the operation unit 36 outputs an operation signal Sop corresponding to the measurement switch 36d to the processing unit 35. When the operation signal Sop is input, the processing unit 35 performs a measurement process for measuring the current value Di of the current I flowing through the conducting wire 100.

  In this measurement process, the processing unit 35 controls the switches 31 and 32 to move the switch 31 to the on state and to move the switch 32 to the off state, as shown in FIG. Further, the processing unit 35 executes control on the switching unit 33 to switch the connection state of the changeover switches SW1 and SW2 as shown in the figure, and the winding end on the proximal end side of the winding 24a is switched to the switching unit. It connects to one input terminal of the measurement part 34 via 33 change-over switch SW1, and the other end of the measurement part 34 is connected to the winding end on the base end side of the winding 24b via the change-over switch SW2 of the changeover part 33. Connect to the terminal. Further, the processing unit 35 controls the invert circuit 37b to shift the invert circuit 37b to a disconnected connection state in which all the switches SW3 to SW6 are turned off as shown in FIG.

  As a result, the winding end on the distal end side of the winding 24a and the winding end on the distal end side of the winding 24b are connected via the switch 31, and the winding end on the proximal end side of the winding 24a as described above. Is connected to one input terminal of the measurement unit 34 via the changeover switch SW1, and the winding end on the proximal end side of the winding 24b is connected to the other input terminal of the measurement unit 34 via the changeover switch SW2. Therefore, the winding 24a and the winding 24b are connected in series, and are connected between the pair of input terminals of the measurement unit 34. Note that the winding end on the tip end side of the winding 24a and the winding end on the tip end side of the winding 24b are in an off state and the invert circuit 37b is in a disconnected connection state. It is in a state of being electrically disconnected from other components.

  In this manner, in the state where the two windings 24a and 24b wound in the same direction as described above are connected in series to the cores 23a and 23b which are one annular core as a whole in the joined state. Since the configuration is such that only the pair of input terminals of the measuring unit 34 is connected, the series-connected windings 24a and 24b function as one winding as a whole, and both winding ends of this one winding. An induced voltage V1 proportional to the current I flowing through the conducting wire 100 is generated between the winding ends of the windings 24a and 24b. The measurement unit 34 inputs the induced voltage V1 from a pair of input terminals via the switching unit 33, calculates a current value Di of the current I based on the input induced voltage V1, and outputs the current value Di to the processing unit 35. To do. Finally, the processing unit 35 stores the current value Di in the storage unit 39 and outputs it to the output unit 40. The output unit 40 inputs the current value Di and displays it on the screen. Thereby, the measurement process is completed.

  Next, the open switch 36c of the operation unit 36 is operated. Thereby, the operation unit 36 outputs an operation signal Sop corresponding to the open switch 36c to the processing unit 35. When the operation signal Sop is input, the processing unit 35 performs a separation process for separating the coil units 22a and 22b of the clamp unit 2.

  In this separation process, the processing unit 35 first executes control on the switches 31 and 32 to shift the switch 31 to the OFF state and shift the switch 32 to the ON state as shown in FIG. As a result, the winding end on the proximal end side of the winding 24a is connected to the plus terminal of the excitation power supply 37a, and the winding end on the distal end side of the winding 24a is connected to the minus terminal of the excitation power supply 37a. Further, the processing unit 35 executes control on the invert circuit 37b, so that the invert circuit 37b is switched to a repulsive connection state in which the switches SW3 and SW6 are turned on and the switches SW4 and SW5 are turned off as shown in FIG. In addition to connecting the winding end on the proximal end side of the winding 24b and the plus terminal of the excitation power source 37a via the switching unit 33 and the invert circuit 37b, by executing control on the switching unit 33, The winding end on the tip end side of the winding 24b and the minus terminal of the excitation power source 37a are connected via the switching unit 33 and the invert circuit 37b.

  Next, the processing unit 35 executes control on the excitation power source 37a to start generation and output of the excitation voltage V2 by the excitation power source 37a. As a result, as shown in FIG. 5, the excitation voltage V2 is supplied to the winding ends on the distal end side and the winding ends on the proximal end side of the windings 24a and 24b constituting the coil portions 22a and 22b. Each coil part 22a, 22b begins to function as an electromagnet. In this case, the excitation voltage V2 is supplied with the polarity shown in FIG. 5 to the winding ends of the windings 24a and 24b on the front end side and the winding ends on the base end side. As shown in the figure, as a result of current flowing in the opposite direction, an N pole is generated on the distal end side (one end of the core 23a) of the coil portion 22a, and S is generated on the proximal end side (the other end of the core 23a). A pole is generated, an N pole is generated on the distal end side (one end of the core 23b) of the coil portion 22b, and an S pole is generated on the proximal end side (the other end of the core 23b). For this reason, one end of the cores 23a and 23b has the same polarity, and the other ends also have the same polarity. As a result, a repulsive force begins to act between the coil portions 22a and 22b.

  Therefore, the urging force of the spring 3c that joins the movable sensor 12 to the fixed sensor 11 is weakened by the repulsive force acting between the coil portions 22a and 22b. For this reason, the force required to push the lever 21c into the main body case 3a and rotate the movable sensor 12 against the urging force of the spring 3c in the direction opposite to the arrow A direction shown in FIG. Since it may be smaller than the state where the repulsive force does not act, the movable side sensor 12 can be easily separated from the fixed side sensor 11, and the clamp part 2 can be easily shifted to the unclamped state. As a result, the lead wire 100 introduced into the sensors 11 and 12 is pulled out of the sensors 11 and 12 through the tip portions 11a and 12a of the sensors 11 and 12 that are separated from each other. It becomes possible to remove the conducting wire 100 from the clamp part 2.

  Subsequently, after removing the conducting wire 100 from the clamp part 2, the open switch 36c of the operation part 36 is operated. Thereby, the operation unit 36 outputs an operation signal Sop corresponding to the open switch 36c to the processing unit 35. When the operation signal Sop is input again during execution of the separation processing, the processing unit 35 executes control on the excitation power source 37a and ends generation and output of the excitation voltage V2 by the excitation power source 37a. Thereby, the separation process is completed. Finally, the power switch 36a of the operation unit 36 is operated to stop the supply of the operating voltage from the main power source to each component arranged in the main body case 3a. In addition, after operating the open switch 36c to finish the separation process, the power switch 36a is operated to stop the supply of the operating voltage from the main power supply, and the conductor 100 is removed from the clamp portion 2 instead. The procedure of operating the power switch 36a to stop the supply of the operating voltage from the main power supply may be executed.

  On the other hand, when the measurement of the current value for the current flowing through the other conductor is continued, the clamp unit 2 is clamped to the other conductor while the processing unit 35 continues the separation process, A procedure for operating the closing switch 36b of the operation unit 36 can also be executed. In this case, since the operation signal Sop corresponding to the closing switch 36b is output from the operation unit 36 to the processing unit 35, the processing unit 35 that has input the operation signal Sop ends the separation process as described above. Subsequently, the joining process described above is executed. Thereby, the clamp part 2 transfers to a clamp state, and another conducting wire is clamped by the clamp part 2. Therefore, after that, the operation unit 36 is operated to cause the processing unit 35 to execute the above-described measurement process, whereby the current value of the current flowing through the other conductor is measured.

  By the way, when the joining process or the separation process is performed, as described above, a DC magnetic field is generated in both the sensors 11 and 12, so that residual magnetization may remain in the cores 23 a and 23 b of both the sensors 11 and 12. This residual magnetization may cause an error in current measurement. In such a case, the demagnetization process is executed for the processing unit 35 to demagnetize this residual magnetization.

  Specifically, the demagnetizing switch 36e of the operation unit 36 is operated. As a result, the operation unit 36 outputs an operation signal Sop corresponding to the demagnetization switch 36e to the processing unit 35. When receiving the operation signal Sop, the processing unit 35 executes a degaussing process.

  In the degaussing process, the processing unit 35 first executes control on the switches 31 and 32 to shift the switch 31 to the on state and to move the switch 32 to the off state as shown in FIG. Further, the processing unit 35 controls the invert circuit 37b to shift the invert circuit 37b to a disconnected connection state in which all the switches SW3 to SW6 are turned off as shown in FIG.

  Next, the processing unit 35 executes control on the switching unit 33 to switch the connection state of the changeover switches SW1 and SW2 as shown in FIG. 6, and the winding end on the proximal end side of the winding 24a is switched to the switching unit. The other end of the demagnetizing section 38 is connected to one output terminal of the demagnetizing section 38 via the selector switch SW1 and the winding end on the proximal end side of the winding 24b is connected to the other output of the demagnetizing section 38 via the selector switch SW2 of the switching section 33. Connect to the terminal. As a result, the winding end on the tip end side of the winding 24a and the winding end on the tip end side of the winding 24b are connected via the switch 31, and the winding 24a and the winding 24b are connected in series. In this state, the winding 24a and the winding 24b are connected between the pair of output terminals of the demagnetizing section 38.

  Next, the processing unit 35 performs control on the demagnetizing unit 38 to start generation and output of the demagnetizing voltage V3 by the demagnetizing unit 38, and end generation and output of the demagnetizing voltage V3 after a predetermined time elapses. . As a result, the demagnetizing voltage V3 is applied from the demagnetizing section 38 to the windings 24a and 24b constituting the coil sections 22a and 22b for a predetermined time, and the demagnetizing voltage V3 gradually increases in amplitude as described above. Therefore, the demagnetizing magnetic field is generated in the windings 24a and 24b, and the residual magnetization remaining in the cores 23a and 23b of the sensors 11 and 12 is demagnetized.

  Thus, according to the current measuring apparatus 1, the windings 24a and 24b formed on the cores 23a and 23b so that one ends of the cores 23a and 23b have different polarities and the other ends have different polarities. By providing the excitation unit 37 for supplying the excitation voltage V2 for exciting the windings 24a and 24b to each other, it is possible to apply an attractive force between the sensors 11 and 12 by operating the excitation unit 37. The front end portions 11a and 12a and the base end portions 11b and 12b of both the sensors 11 and 12 can be joined better than the configuration in which both the sensors 11 and 12 are joined only by the urging force of the spring 3c. Therefore, according to the current measuring apparatus 1, unlike the conventional current measuring apparatus, it is not necessary to inspect the coupling state of the sensors 11 and 12 in the clamped state, and as a result, without using the bonding state inspection coil. The measurement accuracy for the current value Di of the current I flowing through the conducting wire 100 can be sufficiently improved. In addition, since the suction force acting between the sensors 11 and 12 reduces the variation in the joining state of the sensors 11 and 12, this can further improve the measurement accuracy.

  Further, according to the current measuring apparatus 1, the windings 24a and 24b formed on the cores 23a and 23b are excited so that one ends of the cores 23a and 23b have the same polarity and the other ends have the same polarity. By providing the excitation unit 37 for supplying the excitation voltage V2 to the windings 24a and 24b, a repulsive force can be applied between the sensors 11 and 12 by operating the excitation unit 37. Therefore, according to the current measuring device 1, the urging force of the spring 3c that joins the movable sensor 12 to the fixed sensor 11 can be weakened by the repulsive force acting between the coil portions 22a and 22b. Therefore, the force required when the lever 21c is pushed into the main body case 3a to rotate the movable sensor 12 against the urging force of the spring 3c can be reduced. As a result, the clamp portion 2 is brought into an unclamped state. It can be easily transferred.

  Further, according to the current measuring device 1, as described above, the demagnetizing section 38 for generating a demagnetizing magnetic field is provided in the windings 24a and 24b of the coil sections 22a and 22b constituting the sensors 11 and 12, respectively. By supplying the exciting voltage V2, which is a DC voltage, to each of the windings 24a, 24b, it is possible to demagnetize the residual magnetization that may remain in the cores 23a, 23b. It is possible to reliably prevent a decrease in the current measurement accuracy.

  Further, according to the current measuring device 1, the current I flowing through the conducting wire 100 is detected by adopting the configuration in which the excitation voltage V2 is supplied to the windings 24a and 24b formed in the cores 23a and 23b. As a result, the coil portions 22a and 22b that function as detection coils can be made to function as electromagnets that generate an attractive force and a repulsive force with respect to both the sensors 11 and 12, and as a result, a separate independent electromagnet is provided in the clamp portion 2. Compared with the configuration in which the dedicated windings for causing the coil portions 22a and 22b to function as electromagnets are formed on the cores 23a and 23b in addition to the windings 24a and 24b, the apparatus configuration is greatly simplified. be able to.

  The current measuring device 1 employs a configuration that can selectively generate both the attractive force and the repulsive force for both the sensors 11 and 12. It is also possible to employ a configuration that generates only one of the repulsive force and the repulsive force. When this configuration is employed, it is not necessary to invert the excitation voltage V2 supplied to the movable side sensor 12, so that the excitation unit 37 Can be configured only by the excitation power source 37a, and the arrangement of the invert circuit 37b can be omitted. As a result, the configuration of the current measuring device can be simplified. Further, when demagnetizing each of the cores 23a and 23b of the clamp unit 2 using a demagnetizer or the like, it is not necessary to provide a demagnetizing function in the current measuring device 1, and therefore the arrangement of the demagnetizing unit 38 is omitted. Of course, it is good. Also in this configuration, the configuration of the current measuring device can be simplified.

DESCRIPTION OF SYMBOLS 1 Current measuring device 3c Spring 11 Fixed side sensor 12 Movable side sensor 23a, 23b Core 24a, 24b Winding 34 Measurement part 37 Excitation part 38 Demagnetization part I Current

Claims (3)

One of the pair of cores configured in a ring shape as a whole in a state where one end of each other and the other end of each other are joined, and one winding provided with one winding formed on the one core A sensor,
A clamped state that includes the other core of the pair of cores and the other winding formed on the other core, and is configured to be joined to and separated from the one sensor, and joined to the one sensor. And the other sensor in which the pair of cores are configured in an annular shape,
A biasing member that biases each of the sensors in the joining direction;
Based on a detection signal generated in each of the windings due to a current flowing in a measurement object surrounded by the pair of cores configured in an annular shape in a state where the sensors are joined by the biasing member. A clamp-type current measuring device including a measuring unit for measuring the current value of the current,
A current measuring apparatus comprising: an excitation unit that supplies an excitation signal having the same polarity at one end of each core and the same polarity at the other end to each of the windings. One of the pair of cores configured in a ring shape as a whole in a state where one end of each other and the other end of each other are joined, and one winding provided with one winding formed on the one core A sensor,
A clamped state that includes the other core of the pair of cores and the other winding formed on the other core, and is configured to be joined to and separated from the one sensor, and joined to the one sensor. And the other sensor in which the pair of cores are configured in an annular shape,
A biasing member that biases each of the sensors in the joining direction;
Based on a detection signal generated in each of the windings due to a current flowing in a measurement object surrounded by the pair of cores configured in an annular shape in a state where the sensors are joined by the biasing member. A clamp-type current measuring device including a measuring unit for measuring the current value of the current,
Excitation signals in which the one ends of the cores have different polarities and the other ends have different polarities, and excitation signals in which the one ends of the respective cores have the same polarity and the other ends have the same polarity A current measuring device comprising an excitation unit that supplies one of the excitation signals selected from among the windings. 3. The current according to claim 1, further comprising a demagnetizing unit that supplies a degaussing signal for generating a demagnetizing magnetic field in each of the windings to demagnetize the residual magnetization remaining in each of the cores. measuring device.

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