JP2017009420A - Method and device for measuring current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current measurement method and device, which allow for identifying a section of a metal plate surface with a current flow and the amount of the current flow without using current measurement means.SOLUTION: A method of measuring current involves: defining a reference potential point and three or more potential measurement points on a surface of a metal plate opposite a surface from which current flows out; measuring a potential difference between the reference point and each of the potential measurement points; and computing an amount of the current flowing out from the metal plate based on the measured potential differences.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a technical field related to electrical measurement, and more particularly to a current measuring method and apparatus for measuring a current flowing out from a metal plate surface.

  In general, it is difficult to accurately observe or measure the phenomenon at the interface. FIG. 1 is a diagram illustrating a state in which a voltage is applied to two overlapping metal plates and a current flows. Moreover, FIG. 2 is a figure which shows a mode that a metal plate is immersed in a solution and corrodes.

For example, as shown in FIG. 1, when a voltage is applied and a current flows in a state where the metal plate B is overlapped on the metal plate A, a plurality of current-carrying parts (three in FIG. The total current value I _total can be measured when there is a current-carrying part), but the position of each current-carrying part is specified and the current value flowing through each current-carrying part (I ₁ , I ₂ , I ₃ ) It is difficult to determine accurately.

Further, as shown in FIG. 2, when the metal plate is immersed in the solution and corroded, an oxidation reaction occurs in the anode part, and atoms M of the metal plate from the metal plate surface to the solution become cations M ^{n +} . Dissolves. In addition, a reduction reaction occurs at the cathode portion. That is, current flows from the metal plate to the solution at the anode portion and from the solution to the metal plate at the cathode portion. If you know the part where the current is flowing and the current value, you can know the location and the degree of corrosion, but it is not possible to accurately measure the current flowing from the metal plate surface to the outside environment. Have difficulty.

  In the case shown in FIG. 1, Patent Document 1 discloses a technique for measuring a potential distribution on the surface of one metal plate and measuring the position of the energization unit from the potential distribution.

  Prior art documents including non-patent documents referred to in the “DETAILED DESCRIPTION OF THE INVENTION” are shown below.

JP 2007-139750 A

"Numerical calculation Basic mathematics of science and engineering 8", Daisuke Takahashi, Iwanami Shoten, pp. 90-96, 2000 "

  The technique disclosed in Patent Document 1 is a method for obtaining the position of the energization portion from the potential distribution generated on the surface of one of the two metal plates when a current flows through the two stacked metal plates. The width direction, the length direction, and the plate thickness direction of the metal plate are x, y, and z directions, respectively, and “current divergence” is obtained for each minute region in the x and y directions. Is what you want.

  When the two-dimensional (x, y) potential distribution measured on the surface of the plate is V (x, y) and the conductivity of the plate is σ, the current density distribution i (x, y) is expressed by equation (A). Given in.

  Then, from the obtained current density distribution, a current divergence D (divergence) is obtained as in the following equation (B).

  Here, Patent Document 1 shows that the potential on the surface of the metal plate can be measured by a conductive wire connected to the surface of the metal plate by soldering or the like.

  In Patent Document 1, a portion where D in Equation (B) is a positive or negative value is determined as a current-carrying portion, and D does not accurately correspond to a current value flowing through the current-carrying portion. Therefore, the value of the current flowing through the energization unit cannot be directly and accurately known from the measured potential.

  Further, in the measurement method of Patent Document 1, a change in potential due to the plate thickness is not taken into consideration. Therefore, when the metal plate for measuring the surface potential distribution is thick to some extent, the surface potential is different from the potential on the opposite side due to the influence of the plate thickness, and the error due to the measurement increases.

  The present invention has been made in view of the circumstances as described above, and it is possible to determine the location and value of the current flowing on the surface of one metal plate without using current measuring means. An object of the present invention is to provide a measurement method and apparatus.

  In order to solve the above problems, the present invention has the following features.

[1] A current measurement method for obtaining a current value of a current flowing from one surface of a metal plate to an external environment,
Determine a potential reference point and three or more potential measurement points on the surface of the metal plate opposite to the surface from which current is flowing,
Measure the potential difference between the reference point and the potential measurement point,
A method for measuring current, characterized in that a current value flowing out of the metal plate is obtained by calculation based on the measured potential difference.

[2] In the method for measuring current according to [1] above,
Determine a reference point for the potential and four potential measurement points;
In calculating the current value by calculation,
A method for measuring current, which is obtained by the following equation (1).

[3] A current measurement method for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
Determining a potential reference point and three or more potential measurement points on the surface of the metal plate opposite to the surface from which current is flowing; and
Measuring a potential difference between the reference point and the potential measurement point, respectively,
A step 3 of obtaining a current value flowing out of the metal plate based on the measured potential difference by calculation;
A method of measuring current, wherein the distribution of current flowing out from the metal plate is determined by repeating Step 1, Step 2, and Step 3 in this order.

[4] A current measurement method for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
Step 0 of measuring the potential at a predetermined potential measuring point over the entire area of the surface of the metal plate opposite to the surface where current is flowing;
Determining a potential reference point and three or more potential measurement points among the potential measurement points;
Measuring a potential difference between the reference point and the potential measurement point, respectively,
A step 3 of obtaining a current value flowing out of the metal plate based on the measured potential difference by calculation;
A method of measuring current, wherein the distribution of current flowing out from the metal plate is determined by repeating Step 1, Step 2, and Step 3 in this order.

[5] In the method for measuring current according to [3] or [4] above,
In step 1, a reference point of potential and four potential measurement points are determined,
In calculating the current value in step 3 above,
A method for measuring a current distribution, which is obtained by the following equation (1).

[6] A current measuring device for obtaining a current value of a current flowing from one surface of a metal plate to an external environment,
A connecting portion connected to a reference point of potential and three or more potential measuring points provided on a surface of the metal plate opposite to a surface from which current flows;
An electrometer for measuring a potential difference between the reference point and the potential measurement point, respectively;
An apparatus for measuring current, comprising: a calculator for calculating a current value flowing out of the metal plate based on the measured potential difference.

[7] In the current measuring device according to [6] above,
The connection part is connected to the reference point of the potential and four potential measurement points,
In calculating the current value by calculation,
A current measuring device obtained by the following equation (1).

[8] A current measuring device for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
A connecting portion connected to a reference point of potential and three or more potential measuring points provided on the surface of the metal plate opposite to the surface from which current is flowing;
An electrometer for measuring a potential difference between the reference point and the potential measurement point, respectively;
Comprising a calculator for calculating a current value flowing out of the metal plate based on the measured potential difference,
A current measuring apparatus, wherein the current distribution is measured by moving the connecting portion according to a predetermined rule.

[9] A current measuring device for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
The metal plate has measurement points provided at a predetermined interval on a surface opposite to a surface from which current flows.
Any one of the measurement points is a potential reference point, and three or more measurement points around the potential reference point are potential measurement points.
A connection portion connected to the reference point of the potential and the potential measurement point;
An electrometer for measuring a potential difference between the reference point and the potential measurement point, respectively;
Comprising a calculator for calculating a current value flowing out of the metal plate based on the measured potential difference,
A current measuring apparatus, wherein the current distribution is measured by moving the connecting portion according to a predetermined rule.

[10] A current measuring device for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
The metal plate is connected to all measurement points provided at a predetermined interval on the surface opposite to the surface from which current flows, and
An electrometer that measures all potentials in advance using the connection portion as a potential measurement point;
Of the potential data stored and stored, the potential measurement point is any one of the potential measurement points, and the potential reference point and three or more points around the potential reference point are measurement points. Comprising a calculator for calculating a current value flowing out from the metal plate based on a potential difference between the reference point and the measurement point from stored potential data corresponding to three or more measurement points;
An apparatus for measuring current, wherein a current distribution is measured by moving a reference point of the potential and three or more measurement points around the reference point of the potential according to a predetermined rule.

[11] In the current measuring device according to any one of [8] to [10],
The potential reference point and the four measurement points are potential measurement points,
In calculating the current value by calculation,
A current measuring device obtained by the following equation (1).

  According to the present invention, since the current flowing out from the metal plate surface is calculated from the potential distribution on the back surface of the metal plate, the current distribution of the current flowing out from the metal plate surface without using an ammeter is obtained. It can be measured without error.

It is a figure which shows a mode that a voltage is applied to two metal plates which overlap and the electric current is flowing. It is a figure which shows a mode that a metal plate is immersed in a solution and corrodes. It is a figure which shows an example of the apparatus structure of this invention. It is a figure which illustrates this invention typically. It is a figure which shows an example of the jig | tool for electric potential measurement. It is a figure which shows the example of a measurement using the electrode provided in the back surface of the metal plate at predetermined intervals. It is a figure which shows an example of the process sequence of this invention. It is a figure which shows another example of the process sequence of this invention. It is a figure explaining a present Example. It is a figure which shows the comparison of the C-experimental value and C-calculated value in a present Example. It is a figure which shows the comparison of the experimental value and estimated value of the electric current in an Example. It is a figure which shows the comparison of the estimated value of an electric current when not considering the constant C, and an experimental value.

  As described above, it is difficult to directly measure the current flowing from one surface (hereinafter, also referred to as a surface) of the metal plate that is in contact with the external environment to the external environment, particularly to continuously measure it. However, if the current can be measured from the surface opposite to the surface of the metal plate (hereinafter also referred to as the back surface), that is, the surface that is not in contact with the external environment, the location and degree of corrosion of the metal plate can be known. I can do it. Here, in order to measure the current flowing from the front surface of the metal plate to the external environment, the current flowing from the metal plate can be obtained by measuring the potential from the back surface.

  However, when the metal plate is thick, an accurate current value cannot be obtained due to the influence of the plate thickness. When the plate thickness of the metal plate is less than 1.0 mm, since the potential change in the z direction (plate thickness direction) is small, the current flowing out from the surface of the metal plate can be obtained from the potential measured on the measurement surface of the metal plate. However, when the plate thickness is about 1.0 mm or more, the change in potential in the z direction becomes large, and the current flowing from the surface of the metal plate cannot be accurately determined from the potential measured on the back surface of the metal plate.

  Therefore, as a result of intensive studies by the present inventors, it has been found that the current value flowing out from the surface of the metal plate can be accurately obtained by measuring the potential at a plurality of locations on the back surface of the metal plate and calculating from the potential difference. I came up with it.

  FIG. 3 is a diagram showing an example of the apparatus configuration of the present invention. In the figure, 1 is a metal plate, 15 is a conducting wire, 20 is an electrometer, and 30 is a calculator.

  A plurality of conductors 15 for potential difference measurement are installed on the surface (back surface) opposite to the surface (front surface) on which the current value of the current flowing out of the metal plate 1 is to be measured. Based on the potential, the calculator 30 calculates the current value flowing out from the surface of the metal plate. The electrometer 20 normally measures the potential between two points, but as shown in FIG. 3, a multi-channel electrometer may be used so that a large number of potentials can be measured simultaneously.

  Here, the potential of the back surface of the metal plate 1 is measured at one potential reference point and three or more potential measurement points. This is because the current cannot be accurately calculated when there are two or less potential measurement points. It goes without saying that more accurate current values can be calculated if the number of potential measurement points is large, but on the other hand, the calculation itself becomes complicated and not only increases the calculation load, but also the accuracy of the calculation result increases the calculation load. It does n’t get as good as it can. Therefore, the following description will be given by taking the case of one potential reference point and four potential measurement points as an example.

  FIG. 4 is a diagram schematically illustrating the present invention. 4A and 4B respectively show a top view of the surface of one metal plate 1 as viewed from above, and a side view of the side surface of the metal plate as viewed from the direction A in the top view.

  As shown in FIG. 4A, a potential reference point p (hereinafter also simply referred to as a reference point) and four potential measurement points (referred to as a, b, c, and d, respectively) are arranged. From the ease of derivation of the equation (1), the four potential measurement points are arranged in a substantially rhombus in the x and y coordinates. That is, as shown in FIG. 4A, the line segment ac connecting the potential measurement points a and c and the line segment bd connecting the potential measurement points b and d are arranged so as to be orthogonal at the position of the reference point p. is important. As described above, if the line segment ac and the line segment bd are arranged so as to be orthogonal to each other at the position of the reference point p, the line segment ac and the line segment bd may not be parallel to the x-axis and the y-axis, respectively. . Note that the current value can be calculated even when there are three or more measurement points, but since the coordinate system is not orthogonal, the calculation becomes complicated and the calculation amount increases.

  Let the thickness of the metal plate 1 for measuring current be t and the conductivity be σ, and let the width direction, length direction, and plate thickness direction of the metal plate 1 be the x, y, and z directions, respectively. Further, the z = 0 plane of the metal plate 1 is the back surface, and the z = t plane is the front surface. Then, it is assumed that the surface of the metal plate 1 is in contact with the external environment, and current flows from the surface of the metal plate 1 to the external environment. The external environment is a medium in which current flows between a metal plate to be measured, such as various liquids, slurries, various gas atmospheres including air, and various types of metals.

The coordinate position of the center position of the surface of the metal plate 1 where the current flows to the outside is (X, Y, t), and the range for estimating the value of the current flowing to the outside is a shaded rectangle (width) ΔX = (ΔX ₁ + ΔX ₂ ) / 2, length ΔY = (ΔY ₁ + ΔY ₂ ) / 2). The total current value flowing from this range to the external environment is I.

When a current flows between the metal plate 1 and the external environment, a potential distribution corresponding to the magnitude of the flowing current is generated on the back surface of the metal plate 1. The state of this potential distribution is measured with an electrometer. Here, the coordinates (X, Y, 0), (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0), (X, Y−ΔY ₂ , 0) of the back surface of the metal plate 1 , Measure the potential at 5 points (X, Y + ΔY ₁ , 0).

Coordinates (X, Y, 0) are set as potential reference points (Ground), and (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0), (X, Y−ΔY ₂ , 0) And (X, Y + ΔY ₁ , 0) as measurement points, coordinates (X, Y, 0) and (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0), (X, Y−ΔY ₂ , 0) and (X, Y + ΔY ₁ , 0) are each measured using an electrometer, and the potential difference at each measurement point is V (X−ΔX ₂ ), Let V (X + ΔX ₁ ), V (Y−ΔY ₂ ), and V (Y + ΔY ₁ ).

  The current value I flowing out from the metal plate is determined by the following equation (1) from the potential at each measurement point thus measured. The expression (1) is obtained by discretizing the above-described expression (B) by a difference method (for example, refer to Non-Patent Document 1). According to the definition of equation (B), the current divergence D is negative when current flows from the metal plate to the outside, and is positive when current flows from the outside to the metal plate. It is reversed.

  As described above, the present invention is a technique for accurately obtaining the current flowing from the plate surface to the outside of the plate from the potential distribution on the surface opposite to the surface from which the current flows to the outside.

  Here, if ΔX and ΔY are made as small as possible, the accuracy of the current value that can be estimated increases, but in reality, it is difficult to provide measurement points on the metal plate at very narrow intervals. Is 5.0 [mm] or more. Further, since the accuracy of the required current value is lowered, ΔX and ΔY are set to 10.0 [mm] or less.

Although the potential reference point has been described here as the center position of the surface of the metal plate (coordinates are (X, Y, 0)), the center of the region where the current is flowing is measured when the current is actually measured. It is not always possible to set a reference point. However, based on the principle of the present invention, the reference points of the potential are (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0), (X, Y−ΔY ₂ , 0), (X , Y + ΔY ₁ , 0) and satisfy the condition of ΔX = (ΔX ₁ + ΔX ₂ ) / 2 and ΔY = (ΔY ₁ + ΔY ₂ ) / 2.

In order to perform measurement easily, electrodes corresponding to the reference point of potential and the four measurement points are set to (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0) , (X, Y−ΔY ₂ , 0), (X, Y + ΔY ₁ , 0), and ΔX = (ΔX ₁ + ΔX ₂ ) / 2, ΔY = (ΔY ₁ + ΔY ₂ ) / 2 If the connection part arranged so as to satisfy the condition is prepared, the potential can be measured and the current value can be obtained by reliably contacting the connection part with the back surface of the metal plate. Further, if the potential is measured by moving this connection portion, the current value at each location can be obtained, and thereby a wide range of current distribution can be obtained.

  FIG. 5 is a diagram illustrating an example of a potential measurement jig. FIG. 5A shows an apparatus configuration example using a potential measurement jig, and FIG. 5B shows a perspective view of the potential measurement jig. In the figure, 10 represents a potential measuring jig, 15 represents a conducting wire, 101 represents a substrate, 102 represents a terminal, and 103 represents a spring.

  The electric potential measuring jig 10 is a jig for easily moving the connecting portion of the metal plate 1, and a plurality (5 in the figure) for connecting the conductive wire 15 to the substrate 101 formed of an insulator of the metal plate 1 or the like. Terminal 102.

  A spring 103 for pressing is arranged in the middle of the conducting wire 15 to the metal plate 1 to ensure connection with the back surface of the metal plate 1. By moving the potential measurement jig 10 along the back surface of the metal plate 1, the connection portion with the metal plate 1 can be moved, and a wide range of current distribution can be obtained.

  Further, a plurality of potential measurement electrodes may be provided in advance on the back surface of the metal plate at predetermined intervals. FIG. 6 is a diagram illustrating an example of measurement using electrodes provided at predetermined intervals on the back surface of the metal plate. In the figure, 1 is a metal plate, 104 is an electrode, 15 is a conducting wire, 20 is an electrometer, and 30 is a calculator.

  The potential can be measured by selecting the electrode 104 for measuring the potential from the plurality of electrodes 104 provided on the back surface of the metal plate 1 at a predetermined interval and connecting the conductive wire 15. At this time, if a potential reference point is appropriately selected, a current distribution can be obtained by measuring the potential between the surrounding measurement points.

  Further, as shown in FIG. 6, it is the same that a plurality of electrodes are provided in advance at a predetermined interval. However, the potentials of all the measurement points are measured at the same time in a state in which the conducting wire 15 is connected to all the provided electrodes 104. Also good. That is, it is also possible to determine one potential reference point, measure the potential at all potential measurement points with respect to the reference point, and obtain the current value from the potential difference between the potential measurement points.

  In this case, the potential reference point may be one of the measurement points of the metal plate 1 or a point other than the measurement point of the metal plate 1. Further, a reference point may be provided outside the metal plate 1. When providing a reference point of potential other than the measurement point of the metal plate 1 or outside the metal plate 1, it is desirable to ground the reference point of potential.

  After obtaining the potential of each measurement point relative to the reference point of the potential, re-calculate the potential difference between the reference point of the current calculation and the surrounding measurement points by using any point of the measurement point as the reference point for current calculation. Thus, the value of the current flowing around the current calculation reference point can be obtained. The current distribution of the metal plate 1 can be obtained by appropriately moving the reference point for current calculation.

  With this configuration, it is possible to obtain a current distribution at an arbitrary time. This is a more preferable configuration when the current distribution of the metal plate changes with time.

  In addition to the square lattice shown in FIG. 6, the electrode may be disposed in an oblique lattice or hexagonal lattice, for example.

  FIG. 7 is a diagram showing an example of the processing procedure of the present invention. A processing procedure example will be described according to the flow of FIG.

  First, in Step 01, a potential reference point and three or more potential measurement points are determined on the surface opposite to the surface from which current flows. In Step 02, the potential difference between the determined reference point and the potential measurement point is measured.

  Then, in Step 03, based on the potential difference measured in Step 02, the current value flowing out from the metal plate is obtained by calculation from the above-described equation (1). Now, the current value flowing out from the area determined by the reference point and the potential measurement point determined above can be calculated, but in order to calculate the current value flowing out from other areas of the metal plate and obtain the current distribution, The subsequent processing for determining the reference point and three or more potential measurement points, that is, Step 01 to Step 03 are repeated.

  When the current value calculation for all the areas to be obtained is completed in Step 04, the current distribution is output in Step 05 and the process is terminated. The above shows the procedure for obtaining the current distribution from the metal plate by repeating Step 01 to Step 03 while moving the measurement location.

  FIG. 8 is a diagram showing another example of the processing procedure of the present invention. This is different from the previous processing procedure in that a plurality of electrodes are provided in advance in all areas where current distribution is obtained at a predetermined interval and all potentials are measured simultaneously.

  In other words, the potential measurement in the entire area is first performed as Step 00 in FIG. 8 immediately before Step 01 of FIG. 7, and is stored as potential data in the arithmetic unit. In Step 01, the reference point and the measurement point are determined by software in the arithmetic unit, and in Step 02, the potential difference is measured based on the potential data for the determined reference point and measurement point.

  Then, after calculating the current value flowing out from the predetermined area based on the measured potential difference (Step 03), returning to Step 01, the processing up to Step 03 is repeated until it is determined that the current value calculation for all the areas to be obtained in Step 04 is completed. It is the same in that the current distribution is output in Step 05 and the process is terminated.

  Examples carried out to confirm the present invention will be described below. FIG. 9 is a diagram for explaining the present embodiment. A plain steel plate was used as the metal plate. FIGS. 9A and 9B are a top view of the surface of the steel plate as viewed from above and a side view of the steel plate as viewed from the side.

  As shown in FIG. 9, let the width direction, length direction, and plate | board thickness direction of a steel plate be x, y, z direction, respectively. The steel sheet has the z = 0 plane as the back surface and the z = t surface as the front surface. Hereinafter, the specification is expressed in [mm] as necessary.

  The sample was a square of 20 [mm] in the x and y directions, and the thickness t was five types of 0.1 [mm], 0.5 [mm], 1.0 [mm], 5.0 [mm], and 10.0 [mm]. .

Let the coordinates of the center point of the back side of the steel plate be (10, 10, 0). Here, ΔX ₁ = ΔX ₂ = ΔY ₁ = ΔY ₂ = d [mm], and the potential at each potential measurement point is measured. d was 2.5, 5.0, and 7.5 [mm]. That is, when d is 2.5 [mm], ΔX ₁ = ΔX ₂ = ΔY ₁ = ΔY ₂ = 2.5 [mm], and when d is 5.0 [mm], ΔX ₁ = ΔX ₂ = ΔY ₁ = ΔY ₂ When x = 5.0 [mm] and d is 7.5 [mm], ΔX ₁ = ΔX ₂ = ΔY ₁ = ΔY ₂ = 7.5 [mm].

A potential measurement lead wire is connected to each potential measurement point. The coordinates (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0), (X, Y−ΔY ₂ , 0), (X, Y + ΔY ₁ , 0) of the potential measurement point are As described above, when d = 2.5 [mm], (7.5,10.0,0), (12.5,10.0,0), (10.0,7.5,0), (10.0,12.5,0), d = 5.0 When [mm], (5.0,10.0,0), (15.0,10.0,0), (10.0,5.0,0), (10.0,15.0,0), and when d = 7.5 [mm] 2.5,10.0,0), (17.5,10.0,0), (10.0,2.5,0), and (10.0,17.5,0).

Conductive wires were connected to these coordinates on the back surface of the steel plate by soldering so that potential measurement could be performed reliably. With the center point (10,10,0) as the ground reference point (Ground), (X−ΔX ₂ , Y, 0), (X + ΔX ₁ , Y, 0), (X, Y−ΔY ₂ , 0), (X, Y + ΔY ₁ , 0), the potentials measured with respect to the reference point of V (X−ΔX ₂ ), V (X + ΔX ₁ ), V (Y−ΔY ₂ ), respectively. ) And V (Y + ΔY ₁ ). Further, S _x = S _y = dt [mm ² ].

  Here, if the constant C in the equation (1) is clarified, the value of current flowing from the metal plate surface to the external environment can be known from the potential on the back surface of the metal plate. Therefore, in order to create a situation where a current flows between the surface of the metal plate and the external environment, an experimental system was configured so that a current flows through the metal plate, and the potential on the back surface of the metal plate was measured. That is, as shown in FIG. 4 (a), positive (+) and negative (-) electrodes were attached to the metal plate so that current would flow through the metal plate.

  The positive (+) power supply lead (diameter 1 mm) was connected to the center of the four end faces of the steel plate by soldering as shown by the thick dotted line in the figure. The negative (−) power supply lead wire was connected by soldering to the coordinates (10, 10, t) on the surface of the steel plate, as indicated by the thick solid line in the figure. When a voltage is applied to the power feeding unit, a current flows from the periphery of the steel sheet through the center of the steel sheet surface. The current flowing through the negative power supply lead can be measured, and the measured current is I. Further, the current flowing through the four positive power feeding units can also be measured for each power feeding unit, and the sum of them is equal to I.

  On the back surface of the metal plate, as shown in FIG. 9B, a potential measurement lead wire was connected to each measurement point by soldering.

The potential V (X−ΔX ₂ ), V (X + ΔX ₁ ), V on the back side of the metal plate when a voltage is applied so that I = 10.0 A, with the negative lead wire as the reference (Ground) (Y−ΔY ₂ ) and V (Y + ΔY ₁ ) are measured, and σ is a value of iron (1.0 × 10 ⁴ [1 / (Ω · mm)]), and the constant C is calculated from the above equation (1). Asked. Here, as described above, the value of d was changed, and the thickness t was also experimented with 0.1 [mm], 0.5 [mm], 1.0 [mm], 5.0 [mm], 10.0 [mm], and each constant C The value of was obtained. Let these values be C-experimental values.

  On the other hand, the constants a, b, and c were obtained by the equation (2) for each of d = 2.5, 5.0, and 7.5 [mm]. Further, assuming that the plate thickness t is 1.0 [mm], 5.0 [mm], and 10.0 [mm], C obtained by the equation (3), that is, C obtained from these equations is defined as a C-calculated value.

  FIG. 10 is a diagram showing a comparison between C-experimental values and C-calculated values in this example. It can be seen that C (C-calculated value) obtained from the calculation almost coincides with C (C-experimental value) obtained in the experiment. However, from the C-experimental values, it can be seen that the constant C hardly changes when the plate thickness is less than 1.0 [mm]. Therefore, C = 1.1 when the plate thickness is less than 1.0 [mm].

  FIG. 11 is a diagram showing a comparison between an experimental value and an estimated value of current in the example. The estimated current value calculated by the equation (1) using the constant C determined as described above and the experimental value (in this case, 10 [A] constant) are shown together. When the plate thickness is 1.0 [mm], 5.0 [mm], 10.0 [mm], even if d changes to 2.5 [mm], 5.0 [mm], 7.5 [mm], the error is about 5% (at most Is also well within 10.5 [A] for 10 [A]. In addition, when the plate thickness is less than 1.0 [mm], 0.1 [mm] and 0.5 [mm], it seems that there are many variations, but this is because C = 1.1 was constant, but the error is still less than 10% (9 ~ 11 [A]).

  FIG. 12 is a diagram showing a comparison between an estimated current value and an experimental value when the constant C is not considered. That is, it represents an estimated current value when the constant C is C = 1. For example, when the plate thickness is 10.0 [mm] and d is 7.5 [mm], the estimated value is calculated to be slightly over 2 [A] with respect to the experimental value 10 [A]. In this case (thickness is 10.0 [mm] and d is 7.5 [mm]), the estimated accuracy is much higher in the estimated value of 10.5 [A] compared to the experimental value of 10 [A] in FIG. The

  According to the present invention, by measuring the potential distribution on the back surface of the metal plate, the current flowing from the metal plate to the external environment can be accurately obtained without using a current measuring means. Even in environments where it is difficult to directly measure current, the current value can be obtained without using a measuring means such as an ammeter, and the current distribution is also clarified. You can also know.

  Although the above explanation was performed using a normal steel plate, the present invention only needs to be able to measure the potential of the metal plate, and therefore can be applied to other metal plates such as copper plates, aluminum plates, stainless steel plates and the like. Furthermore, if the potential difference at the metal plate can be measured, minute current measurement and current distribution measurement can be performed.

DESCRIPTION OF SYMBOLS 1 Metal plate 10 Electric potential measurement jig | tool 101 Board | substrate 102 Terminal 103 Spring 104 Electrode 15 Conductor 20 Electrometer 30 Calculator

Claims (11)

A current measurement method for obtaining a current value of a current flowing from one surface of a metal plate to an external environment,
Determine a potential reference point and three or more potential measurement points on the surface of the metal plate opposite to the surface from which current is flowing,
Measure the potential difference between the reference point and the potential measurement point,
A method for measuring current, characterized in that a current value flowing out of the metal plate is obtained by calculation based on the measured potential difference. The current measuring method according to claim 1,
Determine a reference point for the potential and four potential measurement points;
In calculating the current value by calculation,
A method for measuring current, which is obtained by the following equation (1).

A current measurement method for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
Determining a potential reference point and three or more potential measurement points on the surface of the metal plate opposite to the surface from which current is flowing; and
Measuring a potential difference between the reference point and the potential measurement point, respectively,
A step 3 of obtaining a current value flowing out of the metal plate based on the measured potential difference by calculation;
A method of measuring current, wherein the distribution of current flowing out from the metal plate is determined by repeating Step 1, Step 2, and Step 3 in this order. A current measurement method for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
Step 0 of measuring the potential at a predetermined potential measuring point over the entire area of the surface of the metal plate opposite to the surface where current is flowing;
Determining a potential reference point and three or more potential measurement points among the potential measurement points;
Measuring a potential difference between the reference point and the potential measurement point, respectively,
A step 3 of obtaining a current value flowing out of the metal plate based on the measured potential difference by calculation;
A method of measuring current, wherein the distribution of current flowing out from the metal plate is determined by repeating Step 1, Step 2, and Step 3 in this order. The current measuring method according to claim 3 or 4,
In step 1, a reference point of potential and four potential measurement points are determined,
In calculating the current value in step 3 above,
A method for measuring a current distribution, which is obtained by the following equation (1).

A current measuring device for obtaining a current value of a current flowing from one surface of a metal plate to an external environment,
A connecting portion connected to a reference point of potential and three or more potential measuring points provided on a surface of the metal plate opposite to a surface from which current flows;
An electrometer for measuring a potential difference between the reference point and the potential measurement point, respectively;
An apparatus for measuring current, comprising: a calculator for calculating a current value flowing out of the metal plate based on the measured potential difference. The current measuring device according to claim 6,
The connection part is connected to the reference point of the potential and four potential measurement points,
In calculating the current value by calculation,
A current measuring device obtained by the following equation (1).

A current measuring device for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
A connecting portion connected to a reference point of potential and three or more potential measuring points provided on the surface of the metal plate opposite to the surface from which current is flowing;
An electrometer for measuring a potential difference between the reference point and the potential measurement point, respectively;
Comprising a calculator for calculating a current value flowing out of the metal plate based on the measured potential difference,
A current measuring apparatus, wherein the current distribution is measured by moving the connecting portion according to a predetermined rule. A current measuring device for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
The metal plate has measurement points provided at a predetermined interval on a surface opposite to a surface from which current flows.
Any one of the measurement points is a potential reference point, and three or more measurement points around the potential reference point are potential measurement points.
A connection portion connected to the reference point of the potential and the potential measurement point;
An electrometer for measuring a potential difference between the reference point and the potential measurement point, respectively;
Comprising a calculator for calculating a current value flowing out of the metal plate based on the measured potential difference,
A current measuring apparatus, wherein the current distribution is measured by moving the connecting portion according to a predetermined rule. A current measuring device for obtaining a current distribution of a current flowing from one surface of a metal plate to an external environment,
The metal plate is connected to all measurement points provided at a predetermined interval on the surface opposite to the surface from which current flows, and
An electrometer that measures all potentials in advance using the connection portion as a potential measurement point;
Of the potential data stored and stored, the potential measurement point is any one of the potential measurement points, and the potential reference point and three or more points around the potential reference point are measurement points. Comprising a calculator for calculating a current value flowing out from the metal plate based on a potential difference between the reference point and the measurement point from stored potential data corresponding to three or more measurement points;
An apparatus for measuring current, wherein a current distribution is measured by moving a reference point of the potential and three or more measurement points around the reference point of the potential according to a predetermined rule. The current measuring device according to any one of claims 8 to 10,
The potential reference point and the four measurement points are potential measurement points,
In calculating the current value by calculation,
A current measuring device obtained by the following equation (1).

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