JP5191712B2 - Current measuring device - Google Patents

Description

  The present invention relates to a pair of sensors that output a detection signal corresponding to a current value of a current flowing through a measurement target object in a ring shape surrounding the measurement target object, and a measurement unit that measures a current based on the detection signal And a clamp-type current measuring device.

As a sensor used in a clamp-type current measuring device, a clamp sensor disclosed by the applicant in Japanese Patent Application Laid-Open No. 11-133303 is known. The clamp sensor includes a fixed side sensor and a movable side sensor each formed in a substantially arc shape. Moreover, in this clamp sensor, when the lever part arrange | positioned at the movable side sensor is pressed, the front-end | tip part of a movable-side sensor separates from the front-end | tip part of a stationary side sensor, and the press with respect to a lever part is cancelled | released. Sometimes, the tip portions of both sensors are joined together by the pressing force of the spring material. In this case, both sensors detect an electrical signal flowing through the conductor under measurement in a state of surrounding the conductor under measurement. On the other hand, in this type of clamp sensor, an electrical signal may not be reliably detected and an error may occur in a measurement result when the tip portions of both sensors are not securely joined. For this reason, this clamp sensor is provided with means for preventing measurement in a state where the tip portions of both sensors are not joined. Specifically, in this clamp sensor, the fixed side sensor is provided with a fixed side contact and the movable side sensor is provided with a movable side contact. When the lever portion is pressed, that is, the leading ends of both sensors are separated. When the two contacts are in contact with each other, the recognition means such as a buzzer is activated. Therefore, in this clamp sensor, since the separation and joining of both sensors can be notified by the operation and stoppage of the recognition means, it is possible to prevent measurement in a state where the tip portions of both sensors are not joined. As a result, accurate measurement is possible.
Japanese Patent Laid-Open No. 11-133303 (page 2-3, FIG. 1)

  However, the above clamp sensor has the following problems to be improved. In other words, in this clamp sensor, the recognition means is activated and deactivated according to the contact and non-contact between the fixed side contact and the movable side contact, thereby recognizing separation and joining of both sensors. However, for example, when both the contacts are worn, there is a possibility that the recognition means may operate because both the contacts are not in contact with each other even though both sensors are actually joined. Also, for example, when a foreign object is caught between the tip portions of both sensors, there is a possibility that both the contacts will be in contact with each other and the recognition means will be deactivated even though both sensors are not actually joined. There is. In other words, the clamp sensor may be notified of a joint state different from the actual joint state of both sensors, and improvement of this point is desired.

  The present invention has been made in view of such a problem to be improved, and a main object of the present invention is to provide a current measuring device capable of accurately reporting the joining state of each end of the sensor.

In order to achieve the above object, the current measuring device according to claim 1 is configured such that each end can be contacted and separated by an opening / closing operation, and is configured to form an annular shape when each end is joined to each other. A pair of sensors that output a detection signal corresponding to the current value of the current flowing through the measurement object in a state of surrounding the measurement object and forming the ring, and a measurement unit that measures the current value based on the detection signal A clamp-type current measuring device comprising: a bonding state inspection coil disposed in at least one of the sensors ; and an inspection signal having a frequency different from the frequency of the current flowing through the measurement object. a signal supplying unit for supplying subjected to the bonding state testing coil, said a notifiable notification unit to the bonding state of each end, component and the examination of the frequency of the test signal included in said detection signal And a signal processing unit for extracting a component of a frequency other than the frequency of the signal, the measuring unit, the inspection signal to the bonding state test coil is output from the sensor in a state of being supplied the Based on the frequency component of the inspection signal extracted from the detection signal, the joining state of each end is inspected and notified to the notification unit, and the frequency of the inspection signal extracted from the detection signal is set. The current value is measured based on the frequency component to be excluded . In this case, the “annular” in the present invention means a shape that is closed when surrounding the measurement object, and the “annular” includes a circular shape, an elliptical shape, Arbitrary shapes such as a rectangular shape and a polygonal shape are included.

The current measuring device according to claim 2, wherein, in the current measuring device according to claim 1, wherein the signal supplying unit is configured to switch the frequency of the test signal.

  The current measuring device according to claim 3 is the current measuring device according to claim 1 or 2, wherein the measuring unit does not measure the current value when the ends are separated from each other. The current value is measured when the ends are joined.

According to the current measuring device of claim 1, the detection unit outputs the detection signal output from the sensor in a state where the inspection signal is supplied to the bonding state inspection coil disposed in at least one of the sensors. A conventional clamp sensor that indirectly inspects the joint state of both sensors based on the contact and non-contact of the contacts provided on the sensor by inspecting the joint state of each end based on the signal and notifying the notification unit Unlike the actual joining state, the situation where the joining state different from the actual joining state is notified is reliably prevented, and the joining state can be accurately notified. Therefore, according to the current measuring device, it is possible to prevent measurement in a state where the end state of the sensor is not good, and as a result, it is possible to perform sufficiently accurate measurement. Further, according to the current measuring device, the frequency component of the test signal included in the detection signal can be reliably separated and extracted. For example, the value of the component and a predetermined reference value Can be accurately inspected for the joining state of each end.

According to the current measuring device of claim 2, since the signal supply unit is configured so that the frequency of the detection signal can be switched, the inspection signal having a frequency different from the frequency of the current flowing through the measurement object is joined. it is a Turkey be supplied to the test coil.

  Further, according to the current measuring device according to claim 3, when the tip of each sensor is separated (bonding state is not good), the measuring unit is securely bonded without measuring the current value. Sometimes the current value is measured to avoid measurement in a state where the measurement value may be inaccurate, and the measurement should be made only when the ends are securely joined and the measurement can be performed accurately. Therefore, only accurate measurement values can be notified by display or the like.

  Hereinafter, the best mode of a current measuring device according to the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the current measuring device 1 will be described. A current measuring device 1 shown in FIG. 1 is an example of a current measuring device according to the present invention, and is configured to be able to measure a current flowing through a conducting wire 100 as a measurement object without contact. Specifically, the current measuring device 1 includes a clamp part 2 and a main body part 3.

  As shown in FIG. 1, the clamp unit 2 includes a fixed side sensor 11 a and a movable side sensor 11 b (a pair of sensors in the present invention: hereinafter referred to as “sensor 11” when not distinguished). ). In addition, as shown in FIGS. 1 and 2, the clamp portion 2 is opened and closed as will be described later, and the tip portions 12 a and 12 b (specifically, the tip portions of coil portions 22 a and 22 b described later) of both sensors 11 and Base end portions 13a and 13b (specifically, base end portions of coil portions 22a and 22b described later) are configured to be able to contact and separate from each other (the tip portions 12a and 12b and the base end portions 13a and 13b are the main ends). Corresponding to the end in the invention). In addition, the clamp portion 2 is configured to form an annular shape when the distal end portions 12a and 12b and the proximal end portions 13a and 13b are joined to each other, and surrounds the conductive wire 100 to form an annular shape (the conductive wire 100 In the clamped state), a detection signal Sm corresponding to the current value of the current I flowing through the conducting wire 100 is output (see FIG. 3).

  As shown in FIG. 1, the stationary sensor 11a includes a sensor case 21a and a coil portion 22a. The sensor case 21 a is integrally formed with the main body case 3 a of the main body portion 3. The coil portion 22a includes a core 23 and a winding 24 wound around the core (see FIG. 3 for both), and is disposed in the sensor case 21a.

  As shown in FIG. 1, the movable side sensor 11b includes a sensor case 21b and a coil part 22b (hereinafter also referred to as “coil part 22” when not distinguished from the coil part 22a of the fixed side sensor 11a). . 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 in a direction (the direction of the arrow A shown in the figure) in which the front end of the sensor case 21b abuts on the front end of the sensor case 21a by the spring 3c disposed in the main body case 3a (both sensors 11 are closed). Is being energized. Further, when the lever 21c integrally formed with the sensor case 21b is pushed in the direction of the arrow B shown in FIG. 2, the front end of the sensor case 21b is separated from the front end of the sensor case 21a (both sensors 11). Is configured to be rotated in the direction of opening. Therefore, the clamp portion 2 is brought into contact with the distal end portions and the proximal end portions of the sensor cases 21a and 21b, that is, between the distal end portions 12a and 12b of the sensors 11 and the proximal end portions 13a and 13b by the operation (opening / closing operation) of the lever 21c. It is configured to separate (open and close).

  The coil portion 22b includes a core 23 and a winding 24 (both see FIG. 3) and is disposed in the sensor case 21a. The coil portion 22b is provided with a coil 25 (joining state inspection coil in the present invention) wound around the winding 24 in one turn. In this case, the coil 25 is a coil for inspecting whether or not the distal end portions 12a and 12b and the proximal end portions 13a and 13b of both the sensors 11 are securely joined to each other. A magnetic field is generated by supplying an inspection signal Si (inspection signal in the present invention) from the signal supply unit 31.

  As shown in FIG. 3, the main body 3 includes a signal supply unit 31, a signal processing unit 32, an operation unit 33, a control unit 34, a display unit 35 (notification unit in the present invention), a storage unit 36, and a storage unit 36 The main body case 3a (refer FIG. 1) arrange | positioned is provided and comprised. The signal supply unit 31 outputs an inspection signal Si (for example, alternating current) to the coil 25 disposed in the movable side sensor 11b of the clamp unit 2. In this case, the signal supply unit 31 is configured to be able to switch the frequency C <b> 1 of the inspection signal Si in accordance with the operation of the operation unit 33. The signal processing unit 32 includes an amplification circuit and a filter circuit whose pass band is defined in conjunction with switching of the frequency C1, and the amplification circuit detects the detection signal output from the clamp unit 2 (both sensors 11). While amplifying Sm, the filter circuit extracts the frequency component C1 and the frequency component excluding the frequency C1 included in the detection signal Sm.

  As shown in FIG. 1, the operation unit 33 includes various switches and keys (for example, measurement keys described later) arranged on the front panel of the main body case 3a, and is operated when these are operated. The signal So is output. The control unit 34 controls each unit constituting the main body unit 3 according to the operation signal So output from the operation unit 33. The control unit 34 functions as a measurement unit in the present invention, and measures the current value of the current I flowing through the conductor 100 based on the detection signal Sm processed (the above-described amplification and extraction processing) by the signal processing unit 32. To do. In addition, in the measurement process 50 (see FIG. 4) described later, the control unit 34 joins the distal end portions 12a and 12b of the sensors 11 and the proximal end portions 13a and 13b of the clamp unit 2 based on the detection signal Sm. And the result is displayed on the display unit 35 (notification in the present invention).

  As shown in FIG. 1, the display unit 35 is arranged on the front panel of the main body case 3 a, and according to the control of the control unit 34, the distal end portions 12 a and 12 b and the proximal end portions 13 a and 13 b of both sensors 11 described above. The connection state between each other and the measured value (current value) of the current I measured by the control unit 34 are displayed. The storage unit 36 temporarily stores the measured value of the current I measured by the control unit 34 according to the control of the control unit 34. In addition, the storage unit 36 stores a reference value Is used during the measurement process 50 executed by the control unit 34. In this case, the detection signals output from the sensor 11 in a state where the distal end portions 12a and 12b and the proximal end portions 13a and 13b of both the sensors 11 are securely joined and the inspection signal Si is supplied to the coil 25. The value (for example, voltage value) of the component of the frequency C1 included in Sm is defined as the reference value Is.

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

  When measuring the current value 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 in so that the distal end portions 12a and 12b and the proximal end portions 13a and 13b of both sensors 11 are separated from each other, and then the lever 21c is pushed in a state in which the conducting wire 100 is surrounded by both the sensors 11. Is released. At this time, the stationary sensor 11a is rotated by the urging force of the spring 3c, and the distal end portions 12a and 12b and the proximal end portions 13a and 13b of both sensors 11 are joined to each other. Thereby, as shown in FIG. 1, the conducting wire 100 is clamped by the clamp portion 2.

  Subsequently, the measurement key of the operation unit 33 is operated. At this time, the operation unit 33 outputs an operation signal So corresponding to the measurement key, and the control unit 34 executes the measurement process 50 shown in FIG. 4 according to the operation signal So. In the measurement process 50, the control unit 34 controls the signal supply unit 31 to start outputting the inspection signal Si (step 51). In this case, the inspection signal Si output from the signal supply unit 31 is supplied to the coil 25 disposed in the movable side sensor 11b of the clamp unit 2, and the coil 25 generates a magnetic field.

  On the other hand, the two sensors 11 of the clamp unit 2 output a detection signal Sm corresponding to the strength of the magnetic field in the space formed by the two sensors 11. In this case, when the current I is flowing through the conducting wire 100, the conducting wire 100 generates a magnetic field. For this reason, the detection signal Sm output from both sensors 11 includes a component having the same frequency as the frequency C1 of the inspection signal Si and a component having the same frequency as the frequency C2 of the current flowing through the conducting wire 100. Next, the signal processing unit 32 amplifies the detection signal Sm output from both the sensors 11 and extracts a component of the frequency C1 and a frequency component excluding the frequency C1 included in the detection signal Sm.

  Subsequently, the control unit 34 reads the reference value Is from the storage unit 36 (step 52). Next, the control unit 34 compares the voltage value of the component of the frequency C1 included in the detection signal Sm (hereinafter, this value is also referred to as “detection value Im”) with the read reference value Is, and detects the detection value. It is determined whether Im is greater than or equal to a reference value Is (step 53). In this case, for example, foreign matter or the like is sandwiched between the distal end portions 12a and 12b of the sensor 11 or the proximal end portions 13a and 13b, and the distal end portions 12a and 12b and the proximal end portions 13a and 13b are reliably joined. If not (bonding is insufficient), the magnetic field generated from the coil 25 cannot be detected sufficiently, so that the detection value Im becomes smaller than the reference value Is. At this time, the control unit 34 discriminates the fact and displays, for example, a character or the like indicating that the joined state between the distal end portions 12a and 12b and the proximal end portions 13a and 13b in the sensor 11 is not good. (Step 54), and the measurement process 50 is terminated. Thereby, it is notified that the joining state of the distal end portions 12a and 12b and the proximal end portions 13a and 13b in the sensor 11 is not good. In this case, by notifying that the joining state is not good, it is possible to reliably prevent an error from occurring in the measurement result due to the measurement being performed in this state.

  On the other hand, when the distal end portions 12a and 12b and the proximal end portions 13a and 13b are reliably joined, the magnetic field generated from the coil 25 is reliably detected, and thus the detection value Im becomes equal to or higher than the reference value Is. At this time, the control unit 34 determines that in step 53 described above, and, for example, the distal end portions 12a and 12b and the proximal end portions 13a and 13b are reliably bonded (the bonded state is good). ) Is displayed on the display unit 35 (step 55). Subsequently, the control unit 34 measures the current value of the current I flowing through the conducting wire 100 based on the frequency components excluding the frequency C1 included in the detection signal Sm, and displays the measured value on the display unit 35. (Step 56). As a result, it is informed that the distal end portions 12a and 12b and the proximal end portions 13a and 13b of the sensor 11 are reliably bonded (the bonded state is good), and the measured value of the current I in this state. Is notified.

Here, in the current measuring device 1, the tip portion of each sensor 11 based on the detection signal Sm detected by each sensor 11 in a state where the inspection signal Si is supplied to the coil 25 for bonding state inspection. 12a and 12b and the joining state of the base end portions 13a and 13b are inspected. That is, in this current measuring device 1, it is directly inspected based on the detection signal Sm whether or not the distal end portions 12a and 12b and the proximal end portions 13a and 13b of each actual sensor 11 are reliably joined. It is possible. For this reason, in this current measuring device 1, unlike the conventional clamp sensor that indirectly inspects the joining state of both sensors based on the contact and non-contact of the contacts provided on the sensor, the tip portions 12a and 12b of the sensor 11 are used. When a foreign object or the like is sandwiched between the base ends 13a and 13b or the contact is worn, a situation in which a joining state different from the actual joining state is notified is reliably prevented, and the joining state is accurately reported. It is possible to do. Therefore, in this current measuring device 1, as a result of being able to prevent measurement in a state in which the distal end portions 12a and 12b and the proximal end portions 13a and 13b are not in good condition (separated), sufficient It is possible to perform accurate measurement.

  Moreover, in this electric current measuring apparatus 1, as above-mentioned, when the joining state of front-end | tip parts 12a and 12b and base end parts 13a and 13b is not favorable (it has separated), it is the electric current I which flows into the conducting wire 100 The measurement process 50 is terminated without measuring the current value. That is, the control unit 34 stops when the measurement of the current value is started when the joining state of the distal end portions 12a and 12b and the proximal end portions 13a and 13b in the sensor 11 is not good, and before the measurement is started. Sometimes the measurement is not started. For this reason, the measurement in a state where the measurement value may be inaccurate is avoided, and the distal end portions 12a and 12b and the proximal end portions 13a and 13b are reliably bonded to each other so that the measurement can be performed accurately. Since only the measurement is performed, only an accurate measurement value can be notified.

  As described above, according to the current measuring apparatus 1, the control unit 34 is in the state in which the inspection signal Si is supplied to the bonding state inspection coil 25 disposed in the fixed-side sensor 11a. Based on the detection signal Sm output from the two sensors 11, the joining state of the distal end portions 12 a and 12 b and the proximal end portions 13 a and 13 b in each sensor 11 is inspected and displayed on the display unit 35. Unlike the conventional clamp sensor that indirectly inspects the joining state of both sensors based on the contact and non-contact of the contact point, the situation where the joining state different from the actual joining state is notified is reliably prevented, The joining state can be notified accurately. Therefore, according to the current measuring device 1, it is possible to prevent measurement in a state where the tip end portions 12a and 12b and the base end portions 13a and 13b are not in good condition. It can be carried out.

  Further, according to the current measuring apparatus 1, the signal supply unit 31 is configured so that the frequency C of the detection signal Sm can be switched, so that the inspection signal Si having a frequency C1 different from the frequency C2 of the current I flowing through the conducting wire 100 is obtained. Is supplied to the coil 25, so that the component of the frequency C1 contained in the detection signal Sm can be reliably separated and extracted, so that the tip portion 12a, by comparing the value of the component with the reference value Is, Inspection of the joining state of 12b and base end part 13a, 13b can be performed correctly.

  Further, according to the current measuring apparatus 1, when the control unit 34 is not in good condition (separated) between the distal end portions 12a and 12b and the proximal end portions 13a and 13b of each sensor 11, the current I By measuring the current value when it is securely joined without measuring the current value, measurement in a state where the measured value may be inaccurate is avoided, and the tip portions 12a, 12b and Since the measurement can be performed only when the base end portions 13a and 13b are reliably joined to each other and the measurement can be accurately performed, only an accurate measurement value can be notified by display or the like.

  In addition, this invention is not limited to said structure. For example, the example is applied to the current measuring device 1 in which the clamp unit 2 and the main body unit 3 are integrally configured. However, the present invention is applied to a current measuring device in which the clamp unit 2 and the main body unit 3 are configured separately. You can also.

  Moreover, although the example which employ | adopted the coil 25 comprised by winding 1 turn around the coil | winding 24 was mentioned above, the structure of the coil 25 is not limited to this, The coil of arbitrary turns number can be used. In addition, when the measurement key of the operation unit 33 is operated, the example in which the current value of the current I is measured following the detection of the joining state of the distal end portions 12a and 12b and the proximal end portions 13a and 13b is described above. However, a detection start key for instructing detection processing of the joint state between the distal end portions 12a and 12b and the base end portions 13a and 13b and a measurement key for instructing measurement processing of the current value are provided separately, and It is also possible to adopt a configuration in which each process is performed individually according to the operation.

  Moreover, although it mentioned above about the example which employ | adopted the structure which displays the character etc. which show a joining state on the display part 35, the structure which alert | reports a joining state is not limited to this. For example, a configuration in which the LCD emits light (or light emission is stopped) according to the joining state of the distal end portions 12a and 12b and the proximal end portions 13a and 13b, and the joining of the distal end portions 12a and 12b and the proximal end portions 13a and 13b. It is also possible to adopt a configuration for notifying the state by voice, or a configuration using these in combination.

1 is a front view of a current measuring device 1. FIG. It is a front view of the electric current measurement apparatus 1 of the state which opened the clamp part 2. FIG. 1 is a configuration diagram showing a circuit configuration of a current measuring device 1. FIG. 5 is a flowchart of a measurement process 50.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Current measuring device 11a Fixed side sensor 11b Movable side sensor 12a, 12b Tip part 13a, 13b Base end part 21c Lever 25 Coil 31 Signal supply part 32 Signal processing part 33 Operation part 34 Control part 35 Display part 50 Measurement process 100 Conduction C1 Frequency I Current Si Inspection signal Sm Detection signal

Claims (3)

Each end is configured to be able to contact and separate by opening and closing operation, and is configured to form an annular shape when the respective end portions are joined to each other. A clamp-type current measuring device comprising a pair of sensors that output a detection signal corresponding to a current value of a current flowing through the body, and a measurement unit that measures the current value based on the detection signal,
Wherein the bonding state testing coils disposed on at least one of the sensors, the signal supply section for supplying subjecting the test signals of different frequencies to the bonding state testing coil and the frequency of the current flowing in the measurement object And a signal for extracting a frequency component of the test signal and a frequency component excluding the frequency of the test signal included in the detection signal A processing unit ,
The measuring unit is configured to perform the inspection based on the frequency component of the inspection signal extracted from the detection signal output from the sensor in a state where the inspection signal is supplied to the bonding state inspection coil. A current measuring device that inspects the joining state of the end portion and informs the informing portion thereof , and measures the current value based on a frequency component excluding the frequency of the inspection signal extracted from the detection signal . Wherein the signal supplying unit includes a current measuring device according to claim 1, which is configured to switch the frequency of the test signal.   3. The current measurement according to claim 1, wherein the measurement unit does not measure the current value when the end portions are separated from each other, and measures the current value when the end portions are joined. 4. apparatus.

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