JP2017032287A - Clamp type sensor and measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for re-clamping to a correct direction even if a direction of clamping to an electric wire is wrong.SOLUTION: A clamp type sensor comprises a current sensor part IS which detects a current I flowing through an electric wire 4 being clamped and outputs a detection signal Si3 for current measurement to the outside. The current sensor part IS has: a current detection part 11 which detects the current I and outputs a current detection signal Si; a phase selection part 22 which receives the signal Si and outputs, as the detection signal Si3, selected one of a signal in the same phase therewith and a signal opposite in phase; and a phase determination part 23 which outputs a determination signal Sb indicative of whether the detection signal Si3 is in a correct phase state or wrong phase state for an AC voltage V applied to the electric wire 4. The phase selection part 23 comprises an output part 25 which has a sub-switch 33b configured to select and output one of the two signals as the detection signal Si3, and displays a phase state of the detection signal Si3 for the AC voltage V on the basis of the determination signal Sb.SELECTED DRAWING: Figure 1

Description

  The present invention includes a clamp sensor configured to be able to detect at least an alternating current among an alternating current flowing through the measurement target wire and an alternating voltage of the measurement target wire by clamping the measurement target wire, and the clamp type sensor. The present invention relates to a measuring device.

  As this type of clamp type sensor, the applicant has already proposed the clamp type sensor disclosed in Patent Document 1 below. This clamp type sensor is configured to include a clamp unit and a sensor main body unit that are integrated with each other, and is used by being connected to a separate measurement device main body via wiring (cable).

  In this clamp type sensor, the clamp unit includes a fixed sensor arm, a movable sensor arm, and a holding arm, and clamps the measurement target wire with the fixed sensor arm and the movable sensor arm, and holds the measurement target wire in the clamped state. Thus, it can be pressed against a predetermined part of the fixed sensor arm. In addition, a pair of magnetic cores for forming a closed magnetic path surrounding the measurement target electric wire in the clamped state and a detection coil wound around the magnetic core are disposed in the fixed sensor arm and the movable sensor arm. Yes. The detection coil outputs a current detection signal whose amplitude changes in proportion to the current value of the current flowing through the measurement target electric wire. In addition, a detection electrode for voltage detection is disposed inside a predetermined portion of the fixed sensor arm.

  In addition, the sensor main body of the clamp type sensor has a current measurement unit (current measurement unit in this example) that outputs a current detection signal output from the detection coil to the outside (the measurement device main body via the wiring). , A configuration for converting the current detection signal into current data indicating the instantaneous value and outputting the current data, and a voltage detection unit. This voltage detection unit is configured to include a current-voltage conversion circuit, an integration circuit, a drive circuit, and a photocoupler, and the current flowing through the detection electrode that is capacitively coupled to the measurement target wire in the clamped state (the measurement target wire and the detection circuit). Voltage detection signal whose amplitude changes in proportion to the current value of the current flowing due to the potential difference between the electrodes) and the integration signal for this voltage detection signal (proportional to the potential difference between the measurement target wire and the detection electrode) Then, the integrated signal is output to the outside (the measurement device main body via the wiring) in a state of being electrically insulated from each circuit in the sensor main body portion. In this case, the current-voltage conversion circuit is configured using an operational amplifier, its inverting input terminal is connected to the detection electrode, and its non-inverting input terminal is a reference for the operating voltage for each circuit in the sensor body. It is specified in the voltage. With this configuration, in this clamp type sensor, the detected voltage is in a state that matches the reference voltage.

  In the measurement apparatus having the clamp type sensor and the measurement apparatus main body configured as described above, the processing unit arranged in the measurement apparatus main body passes the current flowing through the measurement target electric wire based on the current data output from the clamp type sensor. Measure the current value. In addition, the voltage generator disposed in the measuring apparatus main body is based on the integrated signal output from the clamp type sensor, and the potential difference (between the measurement target electric wire and the detection electrode) that is the source of the integrated signal. A voltage signal having a voltage value that decreases the potential difference is output and applied (applied) as a reference voltage to the clamp type sensor. In this measuring apparatus, the voltage generation unit executes the above-described operation, whereby the voltage of the voltage signal output from the voltage generation unit is matched with the voltage applied to the measurement target electric wire. The voltage of the voltage signal output from the voltage generator changes so as to follow the voltage applied to the measurement target electric wire when the voltage applied to the measurement target electric wire fluctuates. A state consistent with is maintained.

  In this measuring device, a voltmeter disposed in the measuring device main body measures the voltage of the voltage signal and outputs the measurement data to the processing unit, so that the processing unit outputs the voltage applied to the measurement target electric wire. The voltage value is measured in a non-contact manner (that is, in a metal non-contact state) without being in electrical contact with the metal portion (core wire) of the measurement target electric wire. Further, the processing unit non-contact (metal non-contact) the power value of the power supplied to the load or the like via the measurement target wire based on the current value and the voltage value of the measurement target wire measured in this way. Measure in the state of contact).

JP 2010-25653 A (page 8-10, FIG. 1-2)

  By the way, when using the clamp type sensor currently indicated by the above-mentioned patent documents 1, the direction of the arrow mark currently displayed on the clamp type sensor and the direction where the direction of the current which flows into a measuring object electric wire corresponds are correct. Therefore, it is necessary to clamp the clamp type sensor to the electric wire to be measured. This is because, in the measuring apparatus main body, the current value and the power value are measured in consideration of the phase of the current flowing in the measurement target wire with respect to the voltage applied to the measurement target wire, so the clamping direction is incorrect. As is the case, the phase state of the current detection signal output from the clamp type sensor with respect to the voltage applied to the measurement target wire is the phase state of the current flowing through the measurement target wire with respect to the voltage applied to the measurement target wire. When they do not match (that is, when the former phase state is substantially reversed with respect to the latter phase state), the current value and the power value cannot be measured correctly. In addition, about the voltage value of a measuring object electric wire, it is measured correctly irrespective of the direction of the clamp of a clamp type sensor.

  However, the clamp type sensor disclosed in the above-mentioned Patent Document 1 includes a situation in which an operator unaccustomed to handling the clamp type sensor is clamped in the wrong direction on the measurement target wire, and the current flowing through the measurement target wire in the first place. Even when the orientation of the wire is not known, there is a risk that the measurement target wire may be clamped in the wrong direction. Since it cannot be measured, there is a problem to be improved that it is necessary to change the orientation and re-clamp, which takes time.

  Furthermore, this clamp type sensor clamps the measurement target wire in the correct orientation due to the positional relationship between the measurement target wire and other structures such as other wires in the vicinity and the shape of the clamp part. There is a problem that correct current values and power values cannot be measured when a situation occurs in which it cannot be clamped only in the wrong direction.

  The present invention has been made in view of the problems to be improved, and even if the direction of the clamp to the measurement target wire is incorrect, the clamp type sensor that does not need to be re-clamped in the correct direction, and the clamp type The main object is to provide a measuring device including a sensor.

  In order to achieve the above object, the clamp type sensor according to claim 1 is configured to be capable of clamping the measurement target electric wire, and detects an AC measurement current flowing in the clamped measurement target electric wire to detect the AC measurement current. A clamp-type sensor including a current sensor unit that outputs a current measurement detection signal whose amplitude changes according to the amplitude to the outside. The current sensor unit detects the AC measurement current and detects the AC measurement current. A current detection unit that outputs a current detection signal whose amplitude changes according to the amplitude of the signal, and inputs the current detection signal, and has two signals: a signal in phase with the current detection signal and a signal in phase opposite to the current detection signal A phase selection unit that outputs a selected one of them as the current measurement detection signal, and the current measurement test for the AC voltage applied to the measurement target wire. A determination signal indicating whether the current measurement detection signal is in a correct phase state or an incorrect phase state with respect to the AC voltage is detected based on the phase difference. A phase determination unit for outputting, the phase selection unit having a selection switch for inputting the two signals and selecting one of the two signals and outputting the selected signal as the current measurement detection signal. And an output unit configured to output the phase state of the current measurement detection signal with respect to the AC voltage based on the determination signal.

  In addition, the clamp type sensor according to claim 2 is configured to be able to clamp the measurement target electric wire and detects an AC measurement current flowing through the clamped measurement target electric wire according to the amplitude of the AC measurement current. A clamp-type sensor including a current sensor unit that outputs a current measurement detection signal whose amplitude changes to the outside, wherein the current sensor unit detects the AC measurement current and responds to the amplitude of the AC measurement current. A current detection unit that outputs a current detection signal whose amplitude changes, and inputs the current detection signal and selects one of two signals: a signal in phase with the current detection signal and a signal in phase opposite to the current detection signal A phase selection unit for outputting the detected one as the current measurement detection signal, and a phase difference of the current measurement detection signal with respect to the AC voltage applied to the measurement target wire A phase determination unit that detects and outputs a determination signal indicating whether the current measurement detection signal is in a correct phase state or an incorrect phase state with respect to the AC voltage based on the phase difference The phase selection unit inputs the two signals and outputs the current measurement detection signal of the two signals when the determination signal indicates the erroneous phase state. A signal different from the existing signal is selected and output as a new current measurement detection signal, and when the determination signal indicates the correct phase state, it is output as the current measurement detection signal of the two signals. And a signal selection unit for continuously outputting the signal being output.

  The clamp type sensor according to claim 3 further includes a voltage detection unit that detects the AC voltage and outputs a voltage detection signal having the same phase as the AC voltage in the clamp type sensor according to claim 1 or 2, The phase determination unit detects the phase difference of the current measurement detection signal with respect to the AC voltage by detecting a phase difference of the current measurement detection signal with respect to the voltage detection signal.

  According to a fourth aspect of the present invention, there is provided a measuring apparatus including the clamp sensor according to any one of the first to third aspects, and a voltage measurement detection signal that detects the AC voltage and changes in amplitude according to the amplitude of the AC voltage. Based on the output voltage sensor, the current measurement detection signal output from the clamp sensor, and the voltage measurement detection signal output from the voltage sensor, the current value of the AC measurement current and the measurement target electric wire And a measuring device main body for measuring at least one of the power values of the power supplied via.

  The measuring apparatus according to claim 5 includes a detection electrode capacitively coupled to the measurement target electric wire and operates with a floating voltage based on a reference voltage, and generates a current flowing between the measurement target electric wire and the detection electrode. A voltage detection unit that detects and outputs a voltage measurement detection signal whose amplitude changes according to a potential difference between the reference voltage and the AC voltage based on the detected current, and the phase determination unit The clamp type sensor according to claim 1 or 2, wherein the phase difference of the current measurement detection signal with respect to the AC voltage is detected by detecting a phase difference of the current measurement detection signal with respect to a reference voltage, and the reference voltage A voltage generator that generates an applied voltage to be applied to the clamp-type sensor, and a measuring device main body having a processing unit, and the voltage generator is An operation of changing the voltage value of the applied voltage so that the amplitude of the detection signal for voltage measurement output from the amplifier sensor approaches zero, and the processing unit outputs the signal output from the clamp sensor. Based on the detection signal for current measurement and the applied voltage, the power value of the power supplied via the measurement target electric wire is measured.

  According to the clamp type sensor of the first and second aspects, since the phase selection unit and the phase determination unit are provided, the current is measured regardless of whether the measurement target electric wire is not clamped in the correct direction. Of the two signals, the signal having the same phase as the detection signal and the signal having the opposite phase, a signal in a correct phase state with respect to the AC voltage can be finally output to the outside as a current measurement detection signal. Therefore, according to this clamp type sensor, a signal in a correct phase state with respect to the AC voltage can be finally output as a current measurement detection signal without re-clamping in the correct direction.

  In the clamp type sensor according to the third aspect of the invention, since the voltage detection unit that detects the AC voltage and outputs a voltage detection signal having the same phase as the AC voltage is provided, the phase determination unit determines the current based on the voltage detection signal. It is possible to detect the phase difference of the measurement detection signal and output a determination signal based on this phase difference. Therefore, according to this clamp type sensor, a signal in a correct phase state with respect to the AC voltage can be finally output as a current measurement detection signal by the clamp type sensor alone.

  Therefore, according to the measuring apparatus according to claim 4, comprising the clamp type sensor according to any one of claims 1 to 3, an operation for re-clamping the clamp type sensor with respect to the measurement target electric wire is unnecessary, and At least one of the current value of the measurement current and the power value of the power supplied via the measurement target electric wire can be measured.

  According to the measuring device of claim 5, since the voltage value of the AC voltage can be measured together with the current value of the AC measurement current without preparing a voltage sensor separate from the clamp sensor, the measurement object Based on the measured voltage value and current value, it is possible to measure the power value of the power supplied via the measurement target wire, while eliminating the need to re-clamp the clamp sensor with respect to the wire.

1 is a configuration diagram of a measuring device 1. FIG. It is a block diagram of the clamp type sensor 2 of FIG. It is a block diagram of the other measuring apparatus 1A. It is a block diagram of the clamp type sensor 2A of FIG. It is a block diagram of the measuring apparatus 1B.

  Embodiments of a clamp sensor according to the present invention and a measurement apparatus according to the present invention including the clamp sensor will be described below with reference to the accompanying drawings.

  A measuring apparatus 1 shown in FIG. 1 includes a clamp type sensor 2 and a main unit 3, and determines a current value of an electric current (AC measurement current) I flowing in a measurement target electric wire 4 (hereinafter also simply referred to as “electric wire 4”). It is comprised so that it can measure in non-contact (namely, metal non-contact state), without contacting the metal part (core wire) of 4 electrically. Further, the measuring device 1 is configured to be connectable with a voltage sensor 7 (in this example, a metal contact type voltage probe) separate from the clamp type sensor 2. The voltage sensor 7 detects the AC voltage V applied to the electric wire 4 and detects a voltage measurement detection signal Sv whose amplitude changes in accordance with the amplitude of the AC voltage V (a signal having the same phase as the AC voltage V). Is output to the measuring apparatus 1. As a result, the measuring apparatus 1 measures the voltage value of the AC voltage V based on the voltage measurement detection signal Sv, and calculates the current value of the current I and the power value of the power W supplied via the electric wire 4. Measurement is possible in a state where the phase of the AC voltage V is taken into consideration.

  As shown in FIG. 1, the clamp type sensor 2 includes a clamp part 5 and a sensor main body part 6. In this case, the clamp portion 5 is configured to be able to clamp the electric wire 4 (it is possible to sandwich the electric wire 4 or surround the electric wire 4), and in this example, the current I is detected and the current I is detected. A current detection unit 11 that outputs a current detection signal Si whose amplitude changes according to the amplitude of I is provided. The current detection unit 11 is a constituent element that constitutes a part of the current sensor unit IS. As an example, the magnetic cores 11a and 11b, the detection coil 11c, and the current-voltage conversion unit 11d (in this example, as shown in FIG. 2, a resistor connected between both ends of the detection coil 11c (hereinafter also referred to as a resistor 11d).

  Moreover, the clamp part 5 has a detection electrode 12 (a part of the voltage sensor part VS) for detecting the AC voltage V applied to the electric wire 4 disposed therein. In this example, a configuration in which the AC voltage V is detected by using a voltage Vid (see FIGS. 1 and 2) induced by electrostatic induction on the detection electrode 12 coupled to the electric wire 4 via the capacitance C0. Although employed, although not shown, a configuration in which the AC voltage V is detected using electromagnetic induction by using a magnetic detection coil instead of the detection electrode 12 can also be employed.

  Specifically, the clamp unit 5 has one end (the right end in FIG. 1) fixed to the sensor body 6 and a fixed sensor arm 13 in which the magnetic core 11a and the detection electrode 12 are disposed. The magnetic core 11b and the detection coil 11c wound around the magnetic core 11b are disposed inside, and one end (the right end in the figure) is rotatably attached to the sensor body 6 and the other end The movable sensor arm 14 is configured such that the portion (the left end portion in the figure) can contact and separate from the other end portion (the left end portion in the figure) of the fixed sensor arm 13, and the one end portion of the movable sensor arm 14. A holding arm 15 is provided between the fixed sensor arm 13 and the movable sensor arm 14 and is rotatably attached to the sensor body 6 together with one end. The fixed sensor arm 13, the movable sensor arm 14, and the pressing arm 15 are made of a synthetic resin material having electrical insulation. The holding arm 15 is formed to have a shorter overall length than the fixed sensor arm 13 and the movable sensor arm 14, and rotates in the inner region of the fixed sensor arm 13 and the movable sensor arm 14. The electric wire 4 clamped by the sensor arm 14 has a function of pressing the electric wire 4 near the position where the detection electrode 12 is disposed in the fixed sensor arm 13 at the other end.

  Moreover, the 1st operation lever 16 extended in the opposite direction to the movable sensor arm 14 is attached to the one end part of the movable sensor arm 14, and both are comprised integrally. Further, a second operation lever 17 extending in the opposite direction to the pressing arm 15 is attached to one end portion of the pressing arm 15 so that both are integrally formed. In this case, the first operating lever 16 and the second operating lever 17 close the opening to an opening (not shown) provided on one side wall (upper side wall in FIG. 1) of the sensor main body 6. It is arranged in this way. The second operation lever 17 is disposed in a state of covering the first operation lever 16.

  Further, the first operation lever 16 is always protruded from the opening of the sensor body 6 by a spring (not shown) (for example, a torsion coil spring) disposed in the sensor body 6 (that is, the sensor in FIG. 1). It is biased in the direction of protruding from the upper side wall of the main body 6. As a result, the movable sensor arm 14 to which the first operation lever 16 is attached is always urged by this spring so as to rotate in the direction of the fixed sensor arm 13. On the other hand, the second operation lever 17 is always separated from the first operation lever 16 by a spring (not shown) (coil spring as an example) disposed between the first operation lever 16 and the second operation lever 17. It is urged in a direction (a direction protruding from the opening, that is, a direction protruding from the upper side wall of the sensor main body 6 in FIG. 1). As a result, the holding arm 15 to which the second operation lever 17 is attached is rotated in the direction of the fixed sensor arm 13 by the spring disposed between the first operation lever 16 and the second operation lever 17. Always energized.

  The clamp sensor 2 includes a pressing arm 15 and a second operation lever 17, and employs a preferable configuration in which the electric wire 4 is pressed by the pressing arm 15 in the vicinity of the position where the detection electrode 12 is disposed on the fixed sensor arm 13. However, in such a configuration in which the electric wire 4 is sandwiched between the pressing arm 15 and the fixed sensor arm 13, the detection electrode 12 can be disposed in the pressing arm 15. Further, when the electric wire 4 is clamped by the fixed sensor arm 13 and the movable sensor arm 14, when the voltage Vid having a sufficient amplitude is induced to the detection electrode 12 in the movable sensor arm 14, the pressing arm 15 and the second A configuration in which the operation lever 17 is omitted may be employed. When the pressing arm 15 is omitted, the detection electrode 12 can be disposed on either the fixed sensor arm 13 or the movable sensor arm 14.

  The magnetic cores 11a and 11b disposed in the clamp unit 5 form a closed magnetic circuit that surrounds the electric wire 4 when the clamp unit 5 clamps the electric wire 4 (when the clamp unit 5 is in a closed state). . Moreover, the detection coil 11c detects the change of the magnetic flux in this closed magnetic circuit which changes according to the electric current value of the electric current I which flows through the electric wire 4, and an amplitude changes according to the electric current value of this electric current I (as an example) A current signal whose amplitude changes in proportion to the current value) is generated and supplied to the resistor 11d connected between both ends thereof. The resistor 11d converts this current signal into a current detection signal Si, which is a voltage signal, and outputs it.

  As shown in FIG. 1, the sensor body 6 includes a case 21, a phase selection unit 22 and a phase determination unit 23 that constitute a part of the current sensor unit IS, and a voltage detection that constitutes a part of the voltage sensor unit VS. A unit 24 and an output unit 25 are provided.

  The case 21 is configured using a conductive material (for example, a metal material). In addition, inside the case 21, a phase selection unit 22, a phase determination unit 23, a voltage detection unit 24, and a power supply unit (not shown) for supplying an operating voltage to these components are arranged. Further, the case 21 is provided with a reference voltage for operating voltage (the voltage of the internal ground G in the case 21). With this configuration, the case 21 is provided with a phase selection unit 22, It functions as a guard electrode for the phase determination unit 23 and the voltage detection unit 24. Further, the case 21 has a structure in which the surface thereof is covered with the insulating film RE1 and the occurrence of electric leakage to the operator who operates the sensor body 6 by gripping it can be avoided.

  As shown in FIG. 2, as an example, the phase selection unit 22 includes a non-inversion unit 31, an inversion unit 32, and a selection switch 33. The phase selection unit 22 inputs a current detection signal Si output from the clamp unit 5, and the current detection signal. Si is output as a current measurement detection signal Si3 in one phase state selected from the same phase state that is the same phase as the input phase and the inverted phase state in which the phase is inverted with respect to the input phase (sensor) A function of outputting to the outside of the main body 6, that is, outputting to the outside of the clamp type sensor 2 is provided.

  In this case, the non-inverting unit 31 is configured by, for example, a buffer circuit using an operational amplifier, and receives the current detection signal Si and has the same phase state (same phase state) as the phase at the time of input, the first current detection signal Si1. Output as. The inverting unit 32 is configured by, for example, an inverting amplifier circuit using an operational amplifier, and receives the current detection signal Si and in the inverted phase state in which the phase is inverted with respect to the input phase, the second current detection signal Si2 Output as. As an example, the selection switch 33 is composed of a semiconductor switch such as an analog switch, and is disposed in the case 21. The sub switch 33 b is disposed on the surface of the case 21 so that it can be manually operated by an operator. And is configured. The main switch 33a inputs two signals of the first current detection signal Si1 and the second current detection signal Si2, and any one of the two current detection signals Si1 and Si2 is used as a current measurement detection signal Si3. Output.

  The sub switch 33b is constituted by a push-type switch, for example, and outputs a control signal Sa to the main switch 33a every time it is operated (pressed). Each time the control signal Sa is input, the main switch 33a has two input terminals to which the first current detection signal Si1 and the second current detection signal Si2 are input, and one input to which the current measurement detection signal Si3 is output. An operation of alternately switching the connection state with the output terminal, that is, an operation of alternately outputting the first current detection signal Si1 and the second current detection signal Si2 as the current measurement detection signal Si3 is performed.

  In addition, the main switch 33a is switched to a connection state in which the first current detection signal Si1 is output as the current measurement detection signal Si3 in an initial state (a state immediately after the start of the clamp sensor 2). Although not shown in the figure, the clamp unit 5 is made to clamp the clamp unit 5 in accordance with the direction of the current I flowing through the electric wire 4 (that is, the clamp unit 5 is clamped in the correct direction). An arrow mark is provided for the operator, and the operator normally causes the electric wire 4 to clamp the clamp portion 5 in the correct direction according to the arrow mark, and in this case, without operating the sub switch 33b, This is because the first current detection signal Si1 in the correct phase state with respect to the AC voltage V is output as the current measurement detection signal Si3 as described later.

  Although not shown, the sub switch 33b is constituted by a changeover switch (mechanical switch) having two inputs and one output, for example, and the first current detection signal Si1 and the second current detection signal Si2 are input to the sub switch 33b. The first current detection signal Si1 and the second current detection signal Si2 may be directly switched by the sub switch 33b and output as the current measurement detection signal Si3. Although not shown, it is possible to employ a configuration in which an amplifier is arranged after the selection switch 33 so that the current measurement detection signal Si3 is output at a low impedance, and further an A / D converter is arranged. The current measurement detection signal Si3 (or its instantaneous value data) is output in a state where the current measurement detection signal Si3 is instantaneously separated by using a photocoupler or an insulation transformer. A configuration for outputting to the outside can also be adopted.

  The phase determination unit 23 detects the phase difference θ of the current measurement detection signal Si3 with respect to the AC voltage V applied to the electric wire 4, and detects the current measurement with respect to the AC voltage V based on the phase difference θ. A determination signal Sb indicating that the signal Si3 is in a correct phase state or an incorrect phase state is output. In this example, the phase determination unit 23 is based on a voltage detection signal Sd (voltage having the same phase as the AC voltage V), which will be described later, output from the voltage detection unit 24, and a current measurement detection signal Si3 for this voltage detection signal Sd. The phase difference θ is detected.

  For example, the phase determination unit 23 includes first and second two-system zero-cross detection circuits, a timer circuit, and an arithmetic circuit (all not shown), and the first-system zero-cross detection circuit detects the voltage detection signal Sd. Zero cross point (rising zero cross point or falling zero cross point) is detected, and the zero cross detection circuit of the second system detects the zero cross point (the zero cross point of the voltage detection signal Sd and the zero cross point of the current detection signal Si3). If the same zero crossing point, that is, the rising zero crossing point of the voltage detection signal Sd, is the same rising zero crossing point, and if it is the falling zero crossing point of the voltage detection signal Sd, the same falling zero crossing point) To detect. The zero cross point will be described below as a rising zero cross point, for example. The timer circuit starts measuring two times, the first time and the second time, each time the first system zero cross detection circuit detects the rising zero cross point for the voltage detection signal Sd. When the zero cross detection circuit detects a zero cross point for the current measurement detection signal Si3, the first time data indicating the first time measured up to this point is output to the arithmetic circuit. The timer circuit calculates second time data indicating the second time measured up to this time point when the first system zero cross detection circuit detects the next rising zero cross point for the voltage detection signal Sd. While outputting to a circuit, the measurement of new 1st time and 2nd time is started.

  The arithmetic circuit stores the first time and the second time output from the timer circuit, and each time a new second time is stored, a second time indicating the period of the voltage detection signal Sd and the current measurement detection signal Si3. Thus, the phase difference θ is calculated by dividing the first time indicating the time lag of the current measurement detection signal Si3 with respect to the voltage detection signal Sd and multiplying the obtained division value by the value 360. As a method of detecting the phase difference θ of the current measurement detection signal Si3 with respect to the voltage detection signal Sd, any one of various other known methods other than the above method can be employed.

  Further, the arithmetic circuit compares the calculated phase difference θ with a predetermined reference phase range (± θref), and when the phase difference θ is included in the reference phase range (± θref), the AC voltage A determination signal Sb indicating that the current measurement detection signal Si3 is in a correct phase state with respect to V (in this example, a determination signal of a voltage level (for example, a low level) corresponding to “in a correct phase state”) Sb) is output. On the other hand, when the phase difference θ is not included in the reference phase range (± θref), the arithmetic circuit determines that the current measurement detection signal Si3 is in an incorrect phase state with respect to the AC voltage V. (In this example, a determination signal Sb having a voltage level (for example, high level) corresponding to “in an incorrect phase state”) is output.

  Here, the phase of the current I flowing in the electric wire 4 with respect to the AC voltage V applied to the electric wire 4 is slightly advanced or slightly delayed depending on the line state of the electric wire 4 or the load state receiving power supply from the electric wire 4. However, it is usually within the range of ± 90 °. For this reason, the clamp direction of the clamp unit 5 with respect to the electric wire 4 is correct, and the phase selection unit 22 selects the first current detection signal Si1 and outputs it as the current measurement detection signal Si3 (the above initial state). In this case, the phase difference θ calculated by the phase determination unit 23 is also in the range of ± 90 °. Therefore, in this clamp type sensor 2, in this state, the phase determination unit 23 determines that the determination signal Sb (voltage level is low) indicating that the current measurement detection signal Si3 is in the correct phase with respect to the AC voltage V. The reference phase range (± θref) is defined as ± 90 ° (θref = 90) so that the determination signal Sb) can be output.

  The voltage detection unit 24 is configured by an amplifier circuit having an automatic gain control function, for example, and inputs the voltage Vid induced in the detection electrode 12, and the voltage Vid is set to a predetermined amplitude (a constant amplitude). And converted into a voltage detection signal Sd, which is an AC signal having the same phase as the AC voltage V, and is output. That is, the voltage detection unit 24 detects the AC voltage V in a non-contact state (that is, in a metal non-contact state) without being in electrical contact with the metal portion (core wire) of the electric wire 4 and outputs the voltage detection signal Sd. Output.

  As an example in this example, the output unit 25 includes a display (LED in this example) such as an LED (light emitting diode) and its drive circuit, and is driven to be turned on / off by a determination signal Sb output from the phase determination unit 23. The Further, at least the LED as the indicator is disposed on the surface of the case 21 in a state that can be visually recognized by the operator (in this example, the state exposed from the insulating coating RE1 covering the surface of the case 21). In the output unit 25, for example, the drive circuit turns on the LED when the voltage level of the determination signal Sb is high (voltage level corresponding to an incorrect phase state), and the voltage level of the determination signal Sb is low (correct). When the voltage level corresponds to the phase state), the LED is turned off.

  With this configuration, the operator checks the lighting / extinguishing state of the display unit 25 (in this example, the lighting / extinguishing state of the LEDs constituting the display unit 25). It is possible to determine that the measurement detection signal Si3 is in the wrong phase state, and in the off state, it is possible to determine that the current measurement detection signal Si3 is in the correct phase state with respect to the AC voltage V. In addition, about the output part 25, it is not limited to the structure which uses indicators, such as LED which an operator can visually recognize, What is necessary is just a structure which can discriminate | determine a phase state. For example, the output unit 25 may be configured by a device that outputs a sound such as a buzzer, and may output different sounds depending on whether the phase state is correct or incorrect.

  The main body unit 3 corresponds to a measuring apparatus main body, and as shown in FIG. 1, as an example, the main body unit 3 includes a processing unit 61 and a display unit 62, and via a connector (not shown) disposed in a housing (not shown). The clamp type sensor 2 and the voltage sensor 7 are configured to be detachably connected. The display unit 62 is configured by a monitor device such as a liquid crystal display, for example.

  The processing unit 61 is configured by, for example, a computer having an A / D conversion function, and converts the current measurement detection signal Si3 output from the clamp sensor 2 and the voltage measurement detection signal Sv output from the voltage sensor 7. Based on this, a measurement process is executed to measure (calculate) the voltage value of the AC voltage V, the current value of the current I, and the power value of the power W.

  Specifically, in this measurement process, the processing unit 61 first converts the current measurement detection signal Si3 output from the clamp type sensor 2 into current instantaneous value data by sampling with a sampling clock, and the voltage sensor. The voltage measurement detection signal Sv output from 7 is sampled with the same sampling clock to be converted into voltage instantaneous value data.

  Moreover, in this measurement process, the process part 61 measures the voltage value of the alternating voltage V applied to the electric wire 4 based on this voltage instantaneous value data. Further, the processing unit 61 calculates an absolute value for the current value of the current I flowing through the electric wire 4 based on the current instantaneous value data, and the electric wire 4 based on the current instantaneous value data and the voltage instantaneous value data. The absolute value of the power value of the power W supplied via is calculated.

  In this measurement process, the processing unit 61 determines the polarity of the calculated current value and power value in consideration of the phase of the current I flowing through the wire 4 with respect to the AC voltage V applied to the wire 4, Measure (calculate) the final current value and power value. As an example, the processing unit 61 has a phase difference θ of a signal corresponding to the current I represented by the current instantaneous value data with respect to the signal corresponding to the AC voltage V represented by the voltage instantaneous value data (for example, for the former signal). The phase difference obtained from the rising zero cross point and the rising zero cross point for the latter signal is obtained, and if this phase difference θ is within a range of ± 90 ° (+ 90 °> θ> −90 °), The polarity is determined to be positive, and if the phase difference θ is outside the range of ± 90 ° (θ ≧ | 90 ° |), the polarity is determined to be negative.

  In addition, the processing unit 61 executes display processing, and causes the display unit 62 to display the calculated voltage value of the AC voltage V, the current value of the current I, and the power value of the power W. The processing unit 61 repeatedly executes the above measurement process and display process, for example, at a constant cycle. Thus, the display unit 62 displays the latest values of the voltage value of the AC voltage V, the current value of the current I, and the power value of the power W while being updated.

  Next, the measurement operation of the electric power W or the like by the measurement device 1 will be described together with the operation of the clamp type sensor 2.

  In the measurement, the operator first brings the voltage sensor 7 into electrical contact with the application portion of the AC voltage V (specifically, the core wire through which the current I flows) in the electric wire 4 and the clamp type sensor 2 is connected to the electric wire 4. Clamp part 5 is clamped. At this time, if the direction of the current I flowing in the electric wire 4 is known, the direction of the arrow mark provided on the clamp part 5 is made to coincide with the direction of the current I (with the correct direction), and the clamp part 5 is clamped. To do.

  However, when the clamp portion 5 cannot be clamped in the correct direction on the electric wire 4 due to the positional relationship between the electric wire 4 and another structure such as another electric wire located in the vicinity thereof or the shape of the clamp portion 5, this example In the clamp type sensor 2, the clamp portion 5 may be clamped in a state where the direction of the arrow mark is opposite to the direction of the current I (in the wrong direction). Further, when the direction of the current I flowing through the electric wire 4 is unknown, the clamp portion 5 is clamped to the electric wire 4 in an arbitrary direction.

  In this state, the voltage sensor 7 detects the AC voltage V and outputs a voltage measurement detection signal Sv to the measurement device 1. On the other hand, in the clamp type sensor 2, the current detection unit 11 configured by the magnetic cores 11 a and 11 b, the detection coil 11 c and the resistor 11 d and disposed in the clamp unit 5 detects the current I flowing through the electric wire 4, The current detection signal Si is output to the sensor body 6. In the clamp type sensor 2, a voltage Vid due to electrostatic induction is induced in the detection electrode 12, and this voltage Vid is also output to the sensor body 6.

  In the sensor body 6 of the clamp sensor 2, the phase selector 22 outputs a current measurement detection signal Si3 based on the current detection signal Si. The current measurement detection signal Si3 is output to the outside of the sensor body 6, that is, to the outside of the clamp sensor 2 (specifically, the body unit 3). After the measurement apparatus 1 starts operation, the main switch 33a in the phase selection unit 22 is output from the non-inversion unit 31 in a state where the operation to the sub switch 33b is not performed (initial state). A detection signal Si1 (a signal having the same phase as the current detection signal Si) is output as a current measurement detection signal Si3. Therefore, the first current detection signal Si1 is output as the current measurement detection signal Si3 to the outside of the clamp sensor 2. In the sensor body 6, the voltage detection unit 24 converts the voltage Vid induced in the detection electrode 12 into a voltage detection signal Sd having the same phase as the AC voltage V and outputs the voltage detection signal Sd.

  The phase determination unit 23 receives the voltage detection signal Sd output from the voltage detection unit 24 and the current measurement detection signal Si3 output from the phase selection unit 22, and first, the current measurement detection signal for the voltage detection signal Sd. The phase difference θ of Si3 is calculated (detected). This phase difference θ represents the phase difference of the current measurement detection signal Si3 with respect to the AC voltage V. Next, the phase determination unit 23 compares the calculated phase difference θ with a predetermined reference phase range (± θref, ± 90 ° in this example), and the phase difference θ is within the reference phase range (± θref). Is included in the display unit 25 as a determination signal Sb (in this example, a low-level determination signal Sb) indicating that the current measurement detection signal Si3 is in the correct phase with respect to the AC voltage V. When the output signal is not included in the reference phase range, a determination signal Sb indicating that the current measurement detection signal Si3 is in an incorrect phase state with respect to the AC voltage V (in this example, as an example, a high level The determination signal Sb) is output to the display unit 25.

  Here, when the clamp unit 5 is clamped in the correct orientation with respect to the electric wire 4, the current detection signal Si output from the current detection unit 11 is in a correct phase state with respect to the AC voltage V. Therefore, the current measurement detection signal Si3 which is the first current detection signal Si1 having the same phase as the current detection signal Si is also in a correct phase state with respect to the AC voltage V (that is, the calculated phase difference θ Is included in the reference phase range (± θref). Therefore, the phase determination unit 23 outputs the determination signal Sb (low-level determination signal Sb) indicating that the phase is in the correct phase state to the display unit 25, and the display unit 25 is turned off based on the determination signal Sb. Transition. The operator confirms that the display unit 25 is turned off, so that the current measurement detection signal Si3 is in the correct phase with respect to the AC voltage V (the clamp unit 5 is clamped in the correct direction). And it is determined that the selection switch 33 is not required to be switched.

  On the other hand, when the clamp unit 5 is clamped in the wrong direction with respect to the electric wire 4, the current detection signal Si output from the current detection unit 11 is in an incorrect phase state with respect to the AC voltage V. . Therefore, the current measurement detection signal Si3 which is the first current detection signal Si1 having the same phase as the current detection signal Si is also in an incorrect phase state with respect to the AC voltage V (that is, the calculated phase difference). θ is not included in the reference phase range (± θref). Therefore, the phase determination unit 23 outputs a determination signal Sb (high-level determination signal Sb) indicating that the phase is in an incorrect phase state to the display unit 25, and the display unit 25 is in the lighting state based on the determination signal Sb. Migrate to The operator confirms that the display unit 25 is in the lighting state, so that the current measurement detection signal Si3 is in an incorrect phase with respect to the AC voltage V (the clamp unit 5 is clamped in the wrong direction). It is determined that the selection switch 33 needs to be switched. Therefore, the operator performs an operation on the sub switch 33b.

  In this case, the operated sub switch 33b outputs the control signal Sa to the main switch 33a, and the main switch 33a that receives the control signal Sa executes a switching operation. Thereby, the main switch 33a replaces the first current detection signal Si1 so far with the second current detection signal Si2 output from the inverting unit 32 (a signal whose phase is inverted with respect to the current detection signal Si). ) As a current measurement detection signal Si3. Here, the second current detection signal Si2 is the current detection signal Si output from the current detection unit 11 of the clamp unit 5 clamped to the electric wire 4 in the wrong direction (that is, when clamped in the correct direction). Is a signal obtained by inverting the current detection signal Si) whose phase is inverted. Thereby, the second current detection signal Si2 is in a correct phase state with respect to the AC voltage V.

  Therefore, the current measurement detection signal Si3 which is the second current detection signal Si2 is also in a correct phase state with respect to the AC voltage V (that is, the calculated phase difference θ is within the reference phase range (± θref)). Is included in the status). Therefore, the phase determination unit 23 outputs the determination signal Sb (low-level determination signal Sb) indicating that the phase is in the correct phase state to the display unit 25, and the display unit 25 is turned off based on the determination signal Sb. Transition. The operator confirms that the display unit 25 is turned off, so that the current measurement detection signal Si3 is in the correct phase with respect to the AC voltage V (the clamp unit 5 is clamped in the correct direction). And it is determined that the selection switch 33 is not required to be switched. In this way, the clamp type sensor 2 of the present example has the second current in the correct phase state with respect to the AC voltage V even when the clamp portion 5 is clamped in the wrong direction with respect to the electric wire 4. The detection signal Si2 is output as the current measurement detection signal Si3.

  In the clamp type sensor 2 of this example, as an example, the phase selection unit 22 is configured to output the first current detection signal Si1 as the current measurement detection signal Si3 in the initial state. The operation on the sub switch 33b when the part 5 is clamped in the correct direction and the operation on the sub switch 33b when the unit 5 is clamped in the wrong direction have the above-described operation contents. However, the phase selection unit 22 is configured to output the second current detection signal Si2 as the current measurement detection signal Si3 in the initial state, or the phase selection unit 22 is configured to output the first current detection signal Si1 and the second current detection in the initial state. Even if it is not known which signal Si2 is output as the current measurement detection signal Si3, when the operator confirms that the display unit 25 is in the lit state, the operator performs an operation on the sub switch 33b. Thus, the current measurement detection signal Si3 output from the clamp type sensor 2 can always be in a correct phase state with respect to the AC voltage V.

  In the main unit 3, the processing unit 61 executes a measurement process based on the current measurement detection signal Si 3 output from the clamp sensor 2 and the voltage measurement detection signal Sv output from the voltage sensor 7, and generates an AC voltage. The voltage value of V, the current value of current I, and the power value of power W are measured (calculated), and display processing is executed to measure the measured voltage value of AC voltage V, the current value of current I, and the power of power W. The value is displayed on the display unit 62.

  In the measuring apparatus 1, as described above, the clamp type sensor 2 has the first current detection signal Si1 and the second current regardless of whether the clamp portion 5 is clamped in the correct direction with respect to the electric wire 4. A signal in the correct phase state with respect to the AC voltage V in the detection signal Si2 is finally output as a current measurement detection signal Si3. Therefore, the processing unit 61 uses the current measurement detection signal Si3 to measure the voltage value of the AC voltage V and the current I which are measured in a state where the clamp unit 5 is clamped in the correct direction with respect to the electric wire 4. The voltage value of the AC voltage V, the current value of the current I, and the power value of the power W are measured (calculated) and displayed on the display unit 62.

  Therefore, according to the clamp type sensor 2 and the measuring device 1 including the clamp type sensor 2, the clamp 4 is not clamped in the correct direction with respect to the wire 4. On the other hand, since the voltage value of the same AC voltage V, the current value of the same current I and the power value of the same power W can be measured as when the clamp part 5 is clamped in the correct orientation, The work of re-clamping the clamp portion 5 of the sensor 2 can be made unnecessary.

  In the above-described clamp type sensor 2, the phase selection unit 22 includes a sub switch 33 b that can be manually operated, and a display unit 25, so that the operator can select the sub switch according to whether the display unit 25 is turned on or off. A configuration is adopted in which the current measurement detection signal Si3 in the correct phase state with respect to the AC voltage V is finally output by operating the switch 33b. However, the configuration is not limited to this configuration. 4, a configuration in which the main switch 33 a of the phase selection unit 22 </ b> A is switched by the determination signal Sb output from the phase determination unit 23 is omitted, and the sub switch 33 b and the display unit 25 are omitted. It can also be configured. Hereinafter, the clamp type sensor 2A and the measurement apparatus 1A provided with the clamp type sensor 2A will be described. However, the same components as those of the clamp type sensor 2 and the measurement apparatus 1 are denoted by the same reference numerals and redundant description will be given. Omitted and different configurations will be mainly described.

  As shown in FIG. 3, the measuring apparatus 1A includes a clamp type sensor 2A and a main unit 3. The clamp type sensor 2A includes a clamp unit 5 and a sensor main unit 6A as shown in FIGS. . Further, as shown in FIG. 4, the sensor main body 6 </ b> A constitutes a case 21, a phase selection unit 22 </ b> A and a phase determination unit 23 </ b> A that constitute a part of the current sensor unit IS, and a part of the voltage sensor unit VS. And a voltage detection unit 24.

  As shown in FIG. 4 as an example, the phase selection unit 22A includes a non-inversion unit 31, an inversion unit 32, and a selection switch (signal selection unit) 33, and the selection switch 33 in this example includes a main switch 33a. ing. In addition, the main switch 33a is constituted by a semiconductor switch such as an analog switch as an example, and the determination signal Sb (in this example, not a high level or low level signal but an incorrect phase state as described later) Each time the first current detection signal Si1 and the second current detection signal Si2 are input, and the current measurement detection signal Si3. The operation of alternately switching the connection state with one output terminal from which is output, that is, the operation of alternately outputting the first current detection signal Si1 and the second current detection signal Si2 as the current measurement detection signal Si3 is executed.

  Similarly to the phase determination unit 23 described above, the phase determination unit 23A determines whether the current measurement detection signal Si3 output from the phase selection unit 22A is in a correct phase state with respect to the AC voltage V or an incorrect phase. Determine if it is in a state. On the other hand, unlike the above-described phase determination unit 23, the phase determination unit 23A outputs a determination signal Sb as a pulse signal only when it is determined that the phase state is incorrect.

  Thus, in the clamp type sensor 2A having this configuration, when the clamp unit 5 is clamped in the correct direction with respect to the electric wire 4, the current detection signal Si output from the current detection unit 11 is compared with the AC voltage V. The phase is correct. Therefore, the current measurement detection signal Si3 which is the first current detection signal Si1 having the same phase as the current detection signal Si is also in a correct phase state with respect to the AC voltage V (that is, the calculated phase difference θ Is included in the reference phase range (± θref). Therefore, the phase determination unit 23 determines that the phase is correct and does not output the determination signal Sb. Thus, the first current detection signal Si1 is continuously output as the current measurement detection signal Si3.

  On the other hand, when the clamp unit 5 is clamped in the wrong direction with respect to the electric wire 4, the current detection signal Si output from the current detection unit 11 is in an incorrect phase state with respect to the AC voltage V. . Therefore, the current measurement detection signal Si3 which is the first current detection signal Si1 having the same phase as the current detection signal Si is also in an incorrect phase state with respect to the AC voltage V (that is, the calculated phase difference). θ is not included in the reference phase range (± θref). Therefore, the phase determination unit 23A determines that the phase is incorrect and outputs a determination signal Sb that is a pulse signal to the main switch 33a of the phase selection unit 22A.

  As a result, the main switch 33a performs a switching operation and replaces the first current detection signal Si1 so far with the second current detection signal Si2 output from the inverting unit 32 (with respect to the current detection signal Si). The signal whose phase is inverted is output as the current measurement detection signal Si3. Here, the second current detection signal Si2 is the current detection signal Si output from the current detection unit 11 of the clamp unit 5 clamped to the electric wire 4 in the wrong direction (that is, when clamped in the correct direction). Is a signal obtained by inverting the current detection signal Si) whose phase is inverted. Thereby, the second current detection signal Si2 is in a correct phase state with respect to the AC voltage V.

  Therefore, the current measurement detection signal Si3 which is the second current detection signal Si2 is also in a correct phase state with respect to the AC voltage V (that is, the calculated phase difference θ is within the reference phase range (± θref)). Is included in the status). Therefore, the phase determination unit 23A determines that the phase is correct and does not output the determination signal Sb. Thereby, the second current detection signal Si2 is continuously output as the current measurement detection signal Si3.

  In this way, the clamp type sensor 2A of this example also has the first current detection signal Si1 and the second current detection signal regardless of whether the clamp portion 5 is clamped in the correct direction with respect to the electric wire 4. A signal in the correct phase state with respect to the alternating voltage V in Si2 can be finally output as a current measurement detection signal Si3.

 Thereby, the processing unit 61 of the main unit 3 uses the current measurement detection signal Si3 to measure the voltage value of the AC voltage V measured in a state where the clamp unit 5 is clamped in the correct direction with respect to the electric wire 4. Then, the voltage value of the alternating voltage V, the current value of the current I, and the power value of the power W are measured (calculated) and displayed on the display unit 62.

  Therefore, according to the clamp type sensor 2A and the measuring apparatus 1A including the clamp type sensor 2A, the clamp 4 is not clamped in the correct direction with respect to the wire 4. On the other hand, since the voltage value of the same AC voltage V, the current value of the same current I and the power value of the same power W can be measured as when the clamp part 5 is clamped in the correct orientation, The work of re-clamping the clamp part 5 of the sensor 2A can be made unnecessary.

  In the clamp type sensors 2 and 2A, the AC voltage V is detected (in this example, detected in a non-contact state with the metal), and the voltage detection signal Sd having the same phase as the AC voltage V is output. The phase determination unit 23 detects the phase difference θ of the current measurement detection signal Si3 based on the voltage detection signal Sd and outputs the determination signal Sb based on the phase difference θ. It is possible. Therefore, according to the clamp type sensors 2 and 2A, the clamp type sensors 2 and 2A alone can finally output a signal having a correct phase state with respect to the AC voltage V as the current measurement detection signal Si3. Can do.

  Further, in the clamp type sensors 2 and 2A described above, a configuration is employed in which only the current measurement detection signal Si3 for measuring the current value of the current I flowing through the electric wire 4 is output to the outside. In the clamp type sensor used in the measuring device disclosed in Patent Document 1 (measuring device that measures the voltage value and the power value of the measuring target wire together with the current value without contact) Regardless of whether the clamp is clamped in the correct orientation, the AC voltage applied to the measurement target wire is a current measurement detection signal for measuring the current value of the current flowing through the measurement target wire. However, it is possible to adopt a configuration that enables output in the correct phase state. Hereinafter, the clamp type sensor 2B having this configuration and the measurement apparatus 1B having the clamp type sensor 2B will be described. The same reference numerals are used for the same configurations as the clamp type sensors 2 and 2A and the measurement apparatuses 1 and 1A. In addition, the description which overlaps is abbreviate | omitted and a different structure is mainly demonstrated. As an example, an example in which the configuration of the clamp type sensor 2 of the clamp type sensors 2 and 2A is applied will be described. In addition, although description is abbreviate | omitted, of course, you may apply the structure of 2 A of clamp type sensors.

  As shown in FIG. 5, the measuring device 1B includes a clamp type sensor 2B and a main body unit 3B, and the clamp type sensor 2B includes a clamp portion 5 and a sensor main body portion 6B as shown in FIG. The sensor body 6B includes a case 21, a phase selection unit 22 and a phase determination unit 23 that form part of the current sensor unit IS, a voltage detection unit 41 that forms part of the voltage sensor unit VS, and a display. Part 25. Unlike the measurement devices 1 and 1A, the measurement device 1B can measure the AC voltage V applied to the electric wire 4 without using the voltage sensor 7.

  In this case, the voltage detection unit 41 is the same component (not shown in the figure) as the voltage detection unit (the component denoted by reference numeral 32) in the clamp type sensor constituting the measurement apparatus disclosed in Patent Document 1. Voltage conversion circuit, integration circuit, drive circuit, and photocoupler). The voltage detection unit 41 is a voltage (for example, two voltages Vf + and Vf− having the same absolute value and different polarities) output from a DC / DC converter 66 (described later) of the main unit 3B, and the main unit 3B. The operation is performed using the floating voltages Vf + and Vf− having the reference voltage G as the voltage V4 (applied voltage applied to the case 21 of the clamp sensor 2B) output from the voltage generator 63 described later.

  In addition, as described in the background art, the voltage detection unit 41 has a current that flows through the detection electrode 12 that is capacitively coupled to the electric wire 4 in the clamped state (due to a potential difference Vdi between the electric wire 4 and the detection electrode 12). The voltage detection signal whose amplitude changes in proportion to the current value of the current flowing through the path including both of them and the integral signal (the potential difference Vdi between the electric wire 4 and the detection electrode 12) for this voltage detection signal. And outputs the integrated signal as a voltage measurement detection signal V3a to the outside (main unit 3B via wiring) in a state of being electrically insulated from each circuit in the sensor main unit. . In this case, although not shown, the current-voltage conversion circuit is configured using an operational amplifier, and its inverting input terminal is connected to the detection electrode 12 and its non-inverting input terminal is connected to the case 21 (that is, The non-inverting input terminal is defined by the reference voltage G).

  As shown in FIG. 5, the main unit 3 </ b> B includes a processing unit 61, a display unit 62, a voltage generation unit 63, a voltmeter 64, a main power supply circuit 65, and a DC / DC converter 66. Based on the voltage measurement detection signal V3a output from the clamp type sensor 2B, the voltage generation unit 63 generates the potential difference Vdi (the electric wire 4 and the detection electrode 12) that is the source of the voltage measurement detection signal V3a. A voltage V4 having a voltage value that reduces the potential difference between them is generated and output (applied) as the reference voltage G to the case 21 of the clamp sensor 2B. Thereby, the voltage value of the voltage V4 output from the voltage generation part 63 is made to correspond with the voltage value of the alternating voltage V applied to the electric wire 4. The voltmeter 64 measures the voltage value of the voltage V4 in real time and outputs voltage data Dv indicating the voltage value to the processing unit 61.

  The main power supply circuit 65 is based on the positive voltage Vdd and the negative voltage Vss (the voltage of the ground G1 in the main unit 3B (which is also the reference voltage of the AC voltage V) for operating the above-described components of the main unit 3B. DC voltages having the same absolute value and different polarities are output. The converter 66 is configured as an isolated power source in which the secondary side is electrically insulated from the primary side. Based on the positive voltage Vdd and the negative voltage Vss supplied to the primary side, the converter 66 is connected to the secondary side. Floating voltages (positive voltage Vf + and negative voltage Vf−) with reference to the reference voltage on the side are generated. The floating voltages (positive voltage Vf + and negative voltage Vf−) are supplied to the clamp sensor 2B using the voltage value of the voltage V4 output from the voltage generator 63 as a reference voltage.

  The processing unit 61 measures the current value of the current I flowing through the electric wire 4 based on the current measurement detection signal Si3, and measures the voltage value of the AC voltage V applied to the electric wire 4 based on the voltage data Dv. . Further, the processing unit 61 non-contacts (metal non-contact) the power value of the power W supplied to the load or the like via the electric wire 4 based on the current value and the voltage value of the electric wire 4 thus measured. The state of contact is measured, and the result is displayed on the display unit 62.

  Thus, in this measuring apparatus 1B, the voltage value of the voltage V4 (reference voltage G in the clamp type sensor 2B) output from the voltage generation unit 63 of the main unit 3B and applied to the case 21 of the clamp type sensor 2B is obtained. The voltage value of the AC voltage V applied to the electric wire 4 is maintained in the same state. Therefore, the phase determination unit 23 of the clamp type sensor 2B replaces the voltage detection signal Sd (voltage having the same phase as the AC voltage V) in the measurement devices 1 and 1A with the voltage V4 (reference voltage in the clamp type sensor 2B). G) is input, and the phase difference θ of the current measurement detection signal Si3 with respect to the voltage V4 is detected.

  Therefore, the clamp type sensor 2B is also the same as the clamp type sensor 2 regardless of whether the clamp portion 5 is clamped in the correct direction with respect to the electric wire 4 or not. Of the two current detection signals Si2, a signal in a correct phase state with respect to the AC voltage V can be finally output as a current measurement detection signal Si3.

  Therefore, according to this clamp type sensor 2B and the measuring device 1B provided with this clamp type sensor 2B, the wire 4 is attached to the electric wire 4 regardless of whether the clamp portion 5 is clamped in the correct direction with respect to the electric wire 4. On the other hand, since the voltage value of the same AC voltage V, the current value of the same current I and the power value of the same power W can be measured as when the clamp part 5 is clamped in the correct orientation, The work of re-clamping the clamp portion 5 of the sensor 2 can be made unnecessary. Moreover, according to the measuring apparatus 1B provided with this clamp type sensor 2B, the power value of this electric power W is measured only by the clamp type sensor 2B without preparing the voltage sensor 7 separate from the clamp type sensor 2B. can do.

  In the above measuring apparatuses 1, 1 </ b> A, 1 </ b> B, the current value of the current I flowing through the electric wire 4, the voltage value of the AC voltage V applied to the electric wire 4, and the electric power supplied via the electric wire 4. Although the configuration for measuring all the power values of W is employed, any configuration that measures at least the current value of the current I may be used.

  In the clamp type sensors 2, 2A and 2B, the phase selection units 22 and 22A include the non-inversion unit 31 together with the inversion unit 32. However, the input current detection signal Si is directly used as the first current detection signal Si1. If it can be used, a configuration in which the non-inversion unit 31 is omitted may be employed.

1, 1A, 1B Measuring device 2, 2A, 2B Clamp type sensor 3, 3B Main unit 4 Electric wire 5 Clamp unit 6, 6A, 6B Sensor main unit 11 Current detection unit 12 Detection electrode 22 Phase selection unit 33b Sub switch 23 Phase determination Section 25 Output Section I Current IS Current Sensor Section Sb Determination Signal Si Current Detection Signal Si3 Current Measurement Detection Signal V AC Voltage W Power

Claims (5)

The measurement target electric wire is configured to be clampable, and an AC measurement current flowing through the measurement target electric wire being clamped is detected, and a current measurement detection signal whose amplitude changes according to the amplitude of the AC measurement current is externally provided. A clamp type sensor having a current sensor unit for output,
The current sensor unit detects the AC measurement current and outputs a current detection signal whose amplitude changes according to the amplitude of the AC measurement current. The current sensor unit receives the current detection signal and inputs the current detection signal. A phase selection unit that outputs one of the two signals of the same phase signal and the current detection signal and the opposite phase signal as the current measurement detection signal, and the alternating current applied to the measurement target wire Detecting a phase difference of the current measurement detection signal with respect to a voltage and determining that the current measurement detection signal is in a correct phase state and an incorrect phase state with respect to the AC voltage based on the phase difference. It has a phase determination unit that outputs a determination signal indicating either
The phase selection unit includes a selection switch that inputs the two signals and selects one of the two signals and outputs the selected signal as the current measurement detection signal.
A clamp-type sensor comprising an output unit that outputs the phase state of the current measurement detection signal with respect to the AC voltage based on the determination signal. The measurement target electric wire is configured to be clampable, and an AC measurement current flowing through the measurement target electric wire being clamped is detected, and a current measurement detection signal whose amplitude changes according to the amplitude of the AC measurement current is externally provided. A clamp type sensor having a current sensor unit for output,
The current sensor unit detects the AC measurement current and outputs a current detection signal whose amplitude changes according to the amplitude of the AC measurement current. The current sensor unit receives the current detection signal and inputs the current detection signal. A phase selection unit that outputs one of the two signals of the same phase signal and the current detection signal and the opposite phase signal as the current measurement detection signal, and the alternating current applied to the measurement target wire Detecting a phase difference of the current measurement detection signal with respect to a voltage and determining that the current measurement detection signal is in a correct phase state and an incorrect phase state with respect to the AC voltage based on the phase difference. It has a phase determination unit that outputs a determination signal indicating either
The phase selection unit inputs the two signals, and when the determination signal indicates the erroneous phase state, a signal output as the current measurement detection signal of the two signals A different signal is selected and output as a new current measurement detection signal, and when the determination signal indicates the correct phase state, a signal output as the current measurement detection signal of the two signals A clamp type sensor having a signal selection unit that continuously outputs the signal. A voltage detector that detects the AC voltage and outputs a voltage detection signal in phase with the AC voltage;
The clamp according to claim 1, wherein the phase determination unit detects the phase difference of the current measurement detection signal with respect to the AC voltage by detecting a phase difference of the current measurement detection signal with respect to the voltage detection signal. Type sensor. The clamp type sensor according to any one of claims 1 to 3,
A voltage sensor that detects the AC voltage and outputs a voltage measurement detection signal whose amplitude changes according to the amplitude of the AC voltage;
Based on the current measurement detection signal output from the clamp type sensor and the voltage measurement detection signal output from the voltage sensor, the current value of the AC measurement current and the measurement target electric wire are supplied. A measuring device comprising: a measuring device main body that measures at least one of the power values of the power. It has a detection electrode capacitively coupled to the measurement target electric wire and operates with a floating voltage based on a reference voltage to detect a current flowing between the measurement target electric wire and the detection electrode and based on the detected current A voltage detection unit that outputs a voltage measurement detection signal whose amplitude changes according to a potential difference between the reference voltage and the AC voltage, and the phase determination unit includes the current measurement detection signal with respect to the reference voltage. The clamp type sensor according to claim 1 or 2, wherein the phase difference of the current measurement detection signal with respect to the AC voltage is detected by detecting the phase difference of
A measuring device main body having a voltage generating unit and a processing unit for generating an applied voltage to be applied to the clamp sensor as the reference voltage;
The voltage generation unit performs an operation of changing a voltage value of the applied voltage so that the amplitude of the detection signal for voltage measurement output from the clamp type sensor approaches zero, and the processing unit includes the clamp A measurement device that measures a power value of power supplied via the measurement target electric wire based on the detection signal for current measurement and the applied voltage output from the sensor.

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