JP2570836B2 - Non-contact current detector - Google Patents
Non-contact current detectorInfo
- Publication number
- JP2570836B2 JP2570836B2 JP63305644A JP30564488A JP2570836B2 JP 2570836 B2 JP2570836 B2 JP 2570836B2 JP 63305644 A JP63305644 A JP 63305644A JP 30564488 A JP30564488 A JP 30564488A JP 2570836 B2 JP2570836 B2 JP 2570836B2
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- Prior art keywords
- current
- magnetic field
- transmission
- distribution line
- coil
- Prior art date
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- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は送配電線の電流を非接触で検出する装置に関
する。Description: BACKGROUND OF THE INVENTION The present invention relates to an apparatus for non-contactly detecting current in a transmission and distribution line.
〔従来技術とその課題点〕 従来、送配電線に流れる電流の検出には、パーマロイ
等からなる高透磁率の環状磁性体の回りに２次巻線を巻
いた電流変成器を用い、その中心部に前記送配電線を貫
通させ、前記２次巻線の電流を測定するのが一般的であ
った。しかし、この方式は高価で重い磁性体を必要とす
るだけでなく、送配電線に一時的な過電流が流れ急に電
流が遮断されたとき、磁性体のヒステリシス特性に基づ
く残留磁気が残って、特性が変化し誤差を生じるという
欠点があった。このことは、「PT・CT実務必携」の第23
3頁下から第５行目ないし第２行目に記載されている。
すなわち、「（１）CTの残留磁気CTの一次回路に過電流
が流れた状態で急に電流がしゃ断されたような場合に
は、鉄心のヒステリシス現象に基づく残留磁気が残る。
そのまま使用すると定格電流付近では大きな誤差の変化
はないが、定格電流の10％以下のような低電流で使用す
る場合に誤差の変化が大きい。」とある。[Prior art and its problems] Conventionally, a current transformer in which a secondary winding is wound around a high-permeability annular magnetic body made of permalloy or the like has been used to detect current flowing in a transmission and distribution line. In general, the power transmission and distribution line was penetrated through the section, and the current of the secondary winding was measured. However, this method not only requires an expensive and heavy magnetic material, but also causes a residual magnetism based on the hysteresis characteristics of the magnetic material when a temporary overcurrent flows in the transmission and distribution line and the current is suddenly cut off. However, there is a drawback that characteristics change and errors occur. This is the 23rd part of “PT / CT Practical Handbook”
It is described in the fifth and second lines from the bottom of page 3.
That is, “(1) When the current is suddenly cut off in a state where an overcurrent flows in the primary circuit of the residual magnetic CT of the CT, the residual magnetism based on the hysteresis phenomenon of the iron core remains.
When used as it is, there is no large change in error near the rated current, but when used at a low current of 10% or less of the rated current, the change in error is large. "a.
また、送配電線を貫通させたパーマロイ等からなる高
透磁率の環状磁性体の一部をカットし、この部分にホー
ル素子あるいはホールICを挿入し、その出力から磁界を
計測し、その値から前記送配電線電流を求める方式もあ
る。この方式は、「センサと周辺回路」の第126頁第21
行目ないし第23行目に記載されている。すなわち、「導
体のまわりに磁心を設け、この磁心にギャップを作って
ホール素子などをおくと、電流（交直両用）を非接触で
測定することができます。これは磁心で電流線をはさむ
構造でクリップオン電流計として実用化されていま
す。」とある。しかし、この方式も、前記の電流変成器
と同様に、高価で重い磁性体を必要とするだけでなく、
過電流で特性が変化しやすいという欠点があった。In addition, a part of a high-permeability annular magnetic body made of permalloy or the like penetrated through the transmission and distribution lines is cut, a Hall element or Hall IC is inserted into this part, and the magnetic field is measured from the output, and the value is measured. There is also a method of obtaining the transmission and distribution line current. This method is described in page 126, 21
Lines 23 through 23 describe it. In other words, "If a magnetic core is provided around a conductor, a gap is created in the magnetic core, and a Hall element is placed, the current (for both AC and DC) can be measured in a non-contact manner. It has been put into practical use as a clip-on ammeter. " However, this method, like the current transformer described above, not only requires an expensive and heavy magnetic material, but also
There is a disadvantage that characteristics are easily changed by overcurrent.
また、最近になって、光伝送媒体のファラデー効果に
よる光の偏波面の回転から電流の作る磁界を検出し、そ
の値から送配電線電流を求める方式も開発されたが、精
度が低く、高価格であるという欠点がある。この方式に
ついては、日本電気協会研究発表会論文集第168頁ない
し第169頁「光ファイバ応用電流・電圧センサの開発」
に紹介されており、特にその第168頁（２−１）「光フ
ァイバ電流センサ基礎実験」の項の第１行目ないし第５
行目に「測定原理としては、単一モード光ファイバの持
つファラデー効果を利用する。ファラデー効果とは磁界
と同一方向に直線偏光を光ファイバ中に通すと、偏光方
向が磁界の大きさに比例して回転する現象であり、」と
記載されている。Recently, a method of detecting the magnetic field generated by the current from the rotation of the polarization plane of light due to the Faraday effect of the optical transmission medium and calculating the transmission / distribution line current from the detected value has been developed. There is a disadvantage that it is price. Regarding this method, see the papers of the Institute of Electrical Engineers of Japan, 168 to 169, "Development of Current and Voltage Sensors Using Optical Fiber".
In particular, the first line to the fifth line of the section “Basic experiment of optical fiber current sensor” on page 168 (2-1) are described.
In the line, "The measurement principle uses the Faraday effect of a single-mode optical fiber. When the linearly polarized light is passed through the optical fiber in the same direction as the magnetic field, the polarization direction is proportional to the magnitude of the magnetic field. This is the phenomenon of rotation. "
本発明は、送配電線に流れる電流値を非接触で、高精
度に、しかも安価な装置で測定できる非接触形電流検出
装置を提供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide a non-contact type current detecting device capable of measuring a current value flowing in a transmission and distribution line in a non-contact, high-accuracy, and inexpensive manner.
上記課題点を解決するため、本発明の非接触形電流検
出装置は、被測定電流が流れる送配電線の近傍に置かれ
る検出コイルと、同検出コイルの略中心に置かれる磁界
検出素子と、同磁界検出素子の出力電圧のうちの交流成
分を増幅する増幅器と、同増幅器の増幅率が前記送配電
線の周波数近傍では高く、それ以外の周波数では低くな
るようにする位相補正回路とを有し、前記送配電線が作
る第一の交流磁界と逆位相の第二の交流磁界を作るよう
に、前記増幅器の出力電流を前記検出コイルに流すよう
にしたものである。In order to solve the above problems, the non-contact type current detection device of the present invention, a detection coil placed near the transmission and distribution line through which the current to be measured flows, a magnetic field detection element placed substantially at the center of the detection coil, It has an amplifier that amplifies the AC component of the output voltage of the magnetic field detecting element, and a phase correction circuit that makes the amplification factor of the amplifier high near the frequency of the transmission and distribution line and low at other frequencies. The output current of the amplifier is caused to flow through the detection coil so as to generate a second AC magnetic field having a phase opposite to the first AC magnetic field generated by the transmission and distribution line.
本発明を図面に示した実施例に基づき説明する。 The present invention will be described based on an embodiment shown in the drawings.
第１図は、本発明の構成を示す説明図で、図におい
て、（１）は無限長直線導体からなる電線、（２）は電
線（１）の近傍に設置した検出コイル、（３）は該検出
コイル（２）の略中心点Ｐに設けた磁界検出素子、
（４）は前記検出コイルの検出電流を制御する制御回
路、（５），（６）はコイルの両端子を制御回路に接続
する導線、（７）は前記磁界検出素子（３）の検出信号
を制御回路に導入する導線である。FIG. 1 is an explanatory view showing the configuration of the present invention, in which (1) is an electric wire formed of an infinite-length linear conductor, (2) is a detection coil installed near the electric wire (1), and (3) is A magnetic field detection element provided at a substantially central point P of the detection coil (2);
(4) is a control circuit for controlling the detection current of the detection coil, (5) and (6) are conductors connecting both terminals of the coil to the control circuit, and (7) is a detection signal of the magnetic field detection element (3). Is a lead wire that is introduced into the control circuit.
電線（１）とＰ点との距離をｒとすると、電線（１）
の電流による磁界検出素子（３）の位置における磁界の
大きさH1は式（１）で表わされる。Assuming that the distance between the electric wire (1) and the point P is r, the electric wire (1)
The size H 1 of the magnetic field at the position of the magnetic field detecting element according to the current (3) is expressed by formula (1).
H1＝I/2πｒ …（１） 一方、検出コイル（２）は半径ａ、長さＬ、巻数Ｎの
円筒形とし、該検出コイル（２）に電流ｉを流したとす
ると、Ｐ点における磁界の強さの大きさH2は式（２）で
表わされる。H 1 = I / 2πr (1) On the other hand, assuming that the detection coil (2) has a cylindrical shape having a radius a, a length L, and a number of turns N, and a current i flows through the detection coil (2), the size of H 2 strength of the magnetic field is expressed by equation (2).
H2＝iN/（4a2＋L2）1/2 …（２） Ｐ点にある磁界検出素子（３）はこのH1とH2との合成
磁界に感応し、この合成磁界に比例的に変化する出力電
圧信号を生じるが、制御回路（４）は、該信号を受けて
電流ｉを調整し、この信号電圧が近似的に０となるよう
に、即ち前記H1とH2との合成磁界が近似的に０となるよ
うに制御する。H 2 = iN / (4a 2 + L 2 ) 1/2 (2) The magnetic field detecting element (3) at the point P is sensitive to the combined magnetic field of H 1 and H 2 and is proportional to the combined magnetic field. Although produces an output voltage signal which varies, control circuit (4) adjusts the current i by receiving the signal, so that the signal voltage is approximately 0, ie synthesis of the H 1 and H 2 Control is performed so that the magnetic field becomes approximately zero.
このことから、式（１）と式（２）を等しいとおく
と、式（３）が得られる。From this, if the equations (1) and (2) are equal, the equation (3) is obtained.
Ｉ＝２πriN/（4a2＋L2）1/2 …（３） 式（３）から、電線（１）の電流Ｉはｒ、Ｎ、ａ、Ｌ
を知ることによりコイル（２）の電流ｉから求められる
ことがわかる。コイル（２）の電流を測定するには、こ
のコイルに直列に抵抗器を挿入し、電圧に変換してもよ
いし、又は、コイル（２）に直列に電流計を挿入しても
よい。I = 2πriN / (4a 2 + L 2 ) 1/2 (3) From equation (3), the current I of the wire (1) is r, N, a, L
, It can be understood that it can be obtained from the current i of the coil (2). To measure the current in coil (2), a resistor may be inserted in series with this coil and converted to a voltage, or an ammeter may be inserted in series with coil (2).
式（３）には、磁性体の磁化曲線のような非線形的要
素を含まないので、本発明の方式は本質的に線形性に勝
れており、過電流により変化する要素もないので、過電
流による経時的変化もない。Since the equation (3) does not include a non-linear element such as a magnetization curve of a magnetic material, the method of the present invention is essentially superior in linearity, and has no element that is changed by an overcurrent. There is no change with time due to the current.
前記検出コイル（２）は、単層ソレノイドでもよい
し、多層ソレノイドでもよい。また、必ずしも断面が円
形である必要はなく、長方形、あるいは、正方形、三角
形等であってもよい。さらに、前記の磁界検出素子はコ
イルの中心に置かれなくても、コイルの中心付近に置か
れればよい。また、第２図に示すように、コイル（２）
を（2a）と（2b）とに分割してもよい。この場合、磁界
検出素子（３）の設置位置Ｐは、両コイル（2a）と（2
b）の中間の略中心点が望ましい。The detection coil (2) may be a single-layer solenoid or a multi-layer solenoid. The cross section does not necessarily have to be circular, but may be rectangular, square, triangular or the like. Furthermore, the above-mentioned magnetic field detecting element need not be placed at the center of the coil, but may be placed near the center of the coil. In addition, as shown in FIG.
May be divided into (2a) and (2b). In this case, the installation position P of the magnetic field detecting element (3) is determined by the two coils (2a) and (2
An approximate center point in the middle of b) is desirable.
磁界検出素子としては、例えばホール素子あるいはホ
ールICを採用する。このホールICは出力電圧が磁界の強
さに比例して変化する特性のものとしておく。ホールIC
はホール素子とその出力を増幅する増幅器とを集積化し
たもので、磁界の変化に対する出力電圧の変化がホール
素子と比べて大きい。そのためホール素子と比べて前記
制御回路（４）の利得が小さくてもよい。一方、ホール
素子を用いた場合は、制御回路（４）の利得を大きくす
る必要がある。いずれの場合も、磁界に対する出力電圧
の直線性の良いものが得られる。このようにして本発明
では、直線性のよい測定により精度の高い電流検出がで
きる。As the magnetic field detecting element, for example, a Hall element or a Hall IC is employed. The Hall IC has a characteristic in which the output voltage changes in proportion to the strength of the magnetic field. Hall IC
Is a device in which a Hall element and an amplifier for amplifying the output of the Hall element are integrated, and the change of the output voltage with respect to the change of the magnetic field is larger than that of the Hall element. Therefore, the gain of the control circuit (4) may be smaller than that of the Hall element. On the other hand, when a Hall element is used, it is necessary to increase the gain of the control circuit (4). In either case, a good linearity of the output voltage with respect to the magnetic field can be obtained. In this manner, in the present invention, highly accurate current detection can be performed by measurement with good linearity.
本発明の適用例として、Ｉ＝600A、ｒ＝6cm、Ｎ＝400
0、ａ＝0.5cm、Ｌ＝1cmとしたとき、ｉ＝0.00563Aとい
う結果を得た。また、コイル（２）の巻線として、直径
0.07mmのポリウレタン被覆銅線を用いると、その巻線の
抵抗分は20℃で約660Ωとなる。一方、コイル（２）の
リアクタンス分は50Hzで約34Ωとなる。そのため、前記
のｉ＝0.00563Aの電流が流れたときのコイル（２）の両
端での電圧降下は約3.72Vとなる。この電圧および電流
の大きさは通常のIC化された演算増幅器で駆動できる大
きさであるので、制御回路（４）の電力消費は少ないも
のとなる。この利点はコイル（２）を小形にしたことか
ら生じている。As an application example of the present invention, I = 600 A, r = 6 cm, N = 400
When 0, a = 0.5 cm and L = 1 cm, the result was i = 0.00563A. The winding of the coil (2) has a diameter of
If a 0.07 mm polyurethane-coated copper wire is used, the resistance of the winding will be about 660Ω at 20 ° C. On the other hand, the reactance of the coil (2) is about 34Ω at 50 Hz. Therefore, when the current of i = 0.00563 A flows, the voltage drop across the coil (2) is about 3.72V. Since the magnitudes of the voltage and the current are large enough to be driven by an ordinary operational amplifier formed into an IC, the power consumption of the control circuit (4) is small. This advantage results from the small size of the coil (2).
第３図は、制御回路（４）の構成例を示す。第３図に
おいて、（4a）はIC化された演算増幅器であり、（4b）
は直流カット用コンデンサ、（4c）は演算増幅器（4a）
のバイアス用抵抗器、（4d）及び（4e）は演算増幅器
（4a）の利得を決定する帰還回路用抵抗器、（4f）は帰
還回路用位相補償コンデンサで、抵抗器（4d）、（4e）
及びコンデンサ（4f）により演算増幅器（4a）の帰還回
路を構成している。抵抗器（4d）を小さくした方が前記
帰還回路の帰還率が下がり、演算増幅器（4a）の帰還利
得が上がる。しかし、帰還利得が上がり過ぎると発振を
起こすので、発振を起こさない範囲で、抵抗器（4d）の
値を決める。コンデンサ（4f）は検出コイル（２）のリ
アクタンス分による電流の位相遅れを補償するためのも
ので、発振しない範囲でできるだけ小さくし、演算増幅
器（4a）の帰還利得が高くなるようにする。（4g）は直
流に対する利得を下げ、（4a）のオフセットによる誤差
をなくすためのコンデンサである。（4h）は演算増幅器
（4a）に直流バイアスを与えるための抵抗器であり、そ
の抵抗値は抵抗器（4h）での電圧降下が無視できる範囲
でできる限り大きい方がよい。（4i）はコイル（２）に
流れる電流を電圧に変換するための抵抗器で、その抵抗
値は、検出コイル（２）の直流抵抗分より十分小さい値
とすることが望ましい。FIG. 3 shows a configuration example of the control circuit (4). In FIG. 3, (4a) is an operational amplifier integrated into an IC, and (4b)
Is a DC cut capacitor, (4c) is an operational amplifier (4a)
(4d) and (4e) are feedback circuit resistors that determine the gain of the operational amplifier (4a), and (4f) is a feedback circuit phase compensation capacitor, and the resistors (4d) and (4e) )
The feedback circuit of the operational amplifier (4a) is constituted by the capacitor (4f) and the capacitor (4f). The smaller the resistor (4d), the lower the feedback ratio of the feedback circuit and the higher the feedback gain of the operational amplifier (4a). However, if the feedback gain is too high, oscillation will occur. Therefore, determine the value of the resistor (4d) within a range that does not cause oscillation. The capacitor (4f) is for compensating for the phase delay of the current due to the reactance of the detection coil (2), and is made as small as possible without causing oscillation, and the feedback gain of the operational amplifier (4a) is increased. (4g) is a capacitor for reducing the gain with respect to DC and eliminating the error due to the offset of (4a). (4h) is a resistor for applying a DC bias to the operational amplifier (4a), and its resistance value is preferably as large as possible within a range where the voltage drop in the resistor (4h) can be ignored. (4i) is a resistor for converting a current flowing through the coil (2) into a voltage, and its resistance value is desirably set to a value sufficiently smaller than the DC resistance of the detection coil (2).
上記の各素子の値は実験的に決めることもできるが、
公知のナイキストの安定判別法を用いて、安定な条件を
満たしながら、送配電線電流の周波数でこの回路のルー
プ利得を最大にする条件を解析的に求めてもよい。The value of each of the above elements can be determined experimentally,
The condition for maximizing the loop gain of this circuit at the frequency of the transmission / distribution line current may be analytically obtained by using a known Nyquist stability determination method while satisfying the stable condition.
磁界検出素子（３）よりの信号は、信号線（７）、直
流カットコンデンサ（4b）を経て演算増幅器（4a）に入
力される。演算増幅器（4a）の出力は帰還回路に与えら
れる。演算増幅器（4a）と帰還回路（4d）、（4e）及び
（4f）により帰還増幅器を構成している。演算増幅器
（4a）の出力は、また、検出コイル（２）及び抵抗器
（4i）に電流を流し、磁界検出素子（３）の位置に磁界
を作り、磁界検出素子（３）の信号を小さくする。演算
増幅器（4a）の帰還利得が高い方が磁界検出素子（３）
の信号を小さくできるので、送配電線電流の作る磁界と
検出コイル（２）の作る磁界との平衡点をよりよい精度
で求めることができる。The signal from the magnetic field detection element (3) is input to the operational amplifier (4a) via the signal line (7) and the DC cut capacitor (4b). The output of the operational amplifier (4a) is provided to a feedback circuit. The operational amplifier (4a) and the feedback circuits (4d), (4e) and (4f) constitute a feedback amplifier. The output of the operational amplifier (4a) also causes a current to flow through the detection coil (2) and the resistor (4i) to create a magnetic field at the position of the magnetic field detection element (3), thereby reducing the signal of the magnetic field detection element (3). I do. The higher the feedback gain of the operational amplifier (4a), the higher the magnetic field detection element (3)
Can be reduced, and the equilibrium point between the magnetic field generated by the transmission / distribution line current and the magnetic field generated by the detection coil (2) can be obtained with higher accuracy.
検出コイル（２）に流れる電流ｉの値は、抵抗器（4
i）の出力端子（８）に計測器（９）を接続して測定で
き、このｉの値を知ることにより、前記（３）式より電
線（１）を流れる被測定電流Ｉが算出できる。この場
合、抵抗器（4i）により電圧に変換して電圧測定してい
るが、その代わりにコイル（２）に直列に電流計を挿入
して電流測定してもよい。The value of the current i flowing through the detection coil (2) is determined by the resistor (4
Measurement can be performed by connecting a measuring instrument (9) to the output terminal (8) of (i). By knowing the value of i, the measured current I flowing through the electric wire (1) can be calculated from the equation (3). In this case, the voltage is converted into a voltage by the resistor (4i) and the voltage is measured. Instead, an ammeter may be inserted in series with the coil (2) to measure the current.
本発明は、被測定電流が流れる送配電線の近傍に置か
れる検出コイルと、同検出コイルの略中心に置かれる磁
界検出素子と、同磁界検出素子の出力電圧のうちの交流
成分を増幅する増幅器と、同増幅器の増幅率が前記送配
電線の周波数近傍では高く、それ以外の周波数では低く
なるようにする位相補正回路とを有し、前記送配電線が
作る第一の交流磁界と逆位相の第二の交流磁界を作るよ
うに、前記増幅器の出力電流を前記検出コイルに流すよ
うにしたので、送配電線に流れる電流値を非接触で、直
線性がよく、高精度で検出することができ、しかも安価
な装置で測定できる非接触形電流検出装置を得ることが
できる。The present invention provides a detection coil placed near a transmission and distribution line through which a current to be measured flows, a magnetic field detection element placed substantially at the center of the detection coil, and amplifies an AC component of an output voltage of the magnetic field detection element. An amplifier and a phase correction circuit for increasing the amplification factor of the amplifier near the frequency of the transmission and distribution line and decreasing the amplification factor at other frequencies; Since the output current of the amplifier is caused to flow through the detection coil so as to generate the second alternating magnetic field of the phase, the current value flowing through the transmission and distribution line is detected in a non-contact manner, with good linearity, and with high accuracy. And a non-contact current detection device that can be measured with an inexpensive device.
第１図は本発明の構成を示す概略図、第２図は本発明の
構成要素である検出コイルの実施例を示す斜視図、第３
図は本発明の構成要素である制御回路のブロック図であ
る。 （１）：電線、（２）：検出コイル （３）：磁界検出素子、（４）：制御回路 （4a）：演算増幅器 （4b），（4f），（4g）：コンデンサ （4c），（4d），（4e），（4h），（4i）：抵抗器 （５），（６），（７）：導線 （８）：出力端子 （９）：計測器FIG. 1 is a schematic diagram showing a configuration of the present invention, FIG. 2 is a perspective view showing an embodiment of a detection coil which is a component of the present invention, and FIG.
FIG. 1 is a block diagram of a control circuit which is a component of the present invention. (1): Electric wire, (2): Detection coil (3): Magnetic field detection element, (4): Control circuit (4a): Operational amplifier (4b), (4f), (4g): Capacitor (4c), ( 4d), (4e), (4h), (4i): Resistor (5), (6), (7): Conductor (8): Output terminal (9): Measuring instrument
Claims (1)
れる検出コイルと、同検出コイルの略中心に置かれる磁
界検出素子と、同磁界検出素子の出力電圧のうちの交流
成分を増幅する増幅器と、同増幅器の増幅率が前記送配
電線の周波数近傍では高く、それ以外の周波数では低く
なるようにする位相補正回路とを有し、前記送配電線が
作る第一の交流磁界と逆位相の第二の交流磁界を作るよ
うに、前記増幅器の出力電流を前記検出コイルに流すよ
うにしたことを特徴とする非接触形電流検出装置。A detection coil disposed near a transmission and distribution line through which a current to be measured flows; a magnetic field detection element disposed substantially at the center of the detection coil; and an AC component of an output voltage of the magnetic field detection element is amplified. And a phase correction circuit so that the amplification factor of the amplifier is high near the frequency of the transmission and distribution line and low at other frequencies, and the first AC magnetic field generated by the transmission and distribution line A non-contact current detection device, wherein an output current of the amplifier is caused to flow through the detection coil so as to generate a second alternating magnetic field having an opposite phase.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63305644A JP2570836B2 (en) | 1988-12-01 | 1988-12-01 | Non-contact current detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63305644A JP2570836B2 (en) | 1988-12-01 | 1988-12-01 | Non-contact current detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02150775A JPH02150775A (en) | 1990-06-11 |
| JP2570836B2 true JP2570836B2 (en) | 1997-01-16 |
Family
ID=17947614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63305644A Expired - Fee Related JP2570836B2 (en) | 1988-12-01 | 1988-12-01 | Non-contact current detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2570836B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11092623B2 (en) | 2018-12-11 | 2021-08-17 | Electronics And Telecommunications Research Institute | Current sensor for measuring alternating electromagnetic wave and a current breaker using the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6508163B2 (en) * | 2016-10-31 | 2019-05-08 | 横河電機株式会社 | Current measurement device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50147372A (en) * | 1974-05-15 | 1975-11-26 | ||
| JPH0650341B2 (en) * | 1985-07-23 | 1994-06-29 | 株式会社島津製作所 | Sensor structure of magnetic detector |
-
1988
- 1988-12-01 JP JP63305644A patent/JP2570836B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11092623B2 (en) | 2018-12-11 | 2021-08-17 | Electronics And Telecommunications Research Institute | Current sensor for measuring alternating electromagnetic wave and a current breaker using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02150775A (en) | 1990-06-11 |
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