JPH0620140Y2 - Current measuring device - Google Patents
Current measuring deviceInfo
- Publication number
- JPH0620140Y2 JPH0620140Y2 JP1987105322U JP10532287U JPH0620140Y2 JP H0620140 Y2 JPH0620140 Y2 JP H0620140Y2 JP 1987105322 U JP1987105322 U JP 1987105322U JP 10532287 U JP10532287 U JP 10532287U JP H0620140 Y2 JPH0620140 Y2 JP H0620140Y2
- Authority
- JP
- Japan
- Prior art keywords
- current
- capacitor
- circuit
- discharge
- charging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
Description
【考案の詳細な説明】 ［産業上の利用分野］ 本考案は電流を計測して光出力する電流計測装置に係
り、特に光変換回路を改善したものに関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a current measuring device that measures a current and outputs it as light, and more particularly to an improved current conversion circuit.
［従来の技術］ 光出力タイプの電流計測装置は広範な分野で使用される
が、絶縁度が高いことから特に高電圧・高電流を取扱う
分野で利用されることが多い。これを送電線故障区間標
定システムで用いられる計測装置を例にとって説明す
る。この装置は故障点を標定するために故障時の架空地
線に流れる電流を変成器を用いて光を検知するものであ
る。[Prior Art] An optical output type current measuring device is used in a wide range of fields, but it is often used particularly in a field handling high voltage and high current because of its high insulation. This will be described by taking a measuring device used in the transmission line fault section locating system as an example. In order to locate a fault point, this device uses a transformer to detect the light that flows through the overhead ground wire at the time of a fault.
現在開発されているこの種の電流計測装置としては、ア
ナログ出力タイプとパルス出力タイプの２種類がある。There are two types of current measuring devices that are currently being developed: analog output type and pulse output type.
前者は、例えば「送電線故障区間標定システムの開発」
昭和61年電気学会全国大会，A-166に記載されているよ
うに、電流値の大きさに比例した光出力を出すもので、
ダイナミックレンジを大幅に拡大しずらいという欠点を
有している。The former is, for example, "Development of transmission line fault segment location system".
As stated in A-166, National Conference of the Institute of Electrical Engineers of Japan in 1986, it produces an optical output proportional to the magnitude of the current value.
It has a drawback that it is difficult to greatly expand the dynamic range.
後者は、変成器の飽和特性を利用しており、電流値が大
きくなる程光出力パルス幅が狭くなり、このパルス幅を
計測することによって電流値を計測するものである。ダ
イナミックレンジを広くできるものの、電流に含まれて
いる高調波やノイズの影響を受けやすく、精度上問題が
あった。The latter utilizes the saturation characteristic of the transformer, and the optical output pulse width becomes narrower as the current value increases, and the current value is measured by measuring this pulse width. Although it can widen the dynamic range, it is easily affected by the harmonics and noise contained in the current, causing a problem in accuracy.
このような欠点や問題は送電線故障区間標定システムで
用いられる計測装置に限られるものではなく、他分野の
光式の電流計測装置に当てはまる。Such drawbacks and problems are not limited to the measuring device used in the transmission line fault section locating system, and are applicable to optical current measuring devices in other fields.
［考案が解決しようとする問題点］ 上記したように、アナログ出力タイプの電流計測装置で
はダイナミックレンジを大きくとれず、またパルス出力
タイプのものでは、ダイナミックレンジは大きくとれる
が、精度の点で問題があった。[Problems to be Solved by the Invention] As described above, the analog output type current measuring device cannot have a large dynamic range, and the pulse output type has a large dynamic range, but there is a problem in accuracy. was there.
これらの原因は、前者にあっては２次電流波形そのもの
を光出力に変換することにあり、後者にあっては２次電
流波形の一部を光出力に変換するようにしてあるもの
の、飽和電流のレベル設定、即ち一点設定によってパル
ス幅を得ていることにある。The cause of these is that in the former, the secondary current waveform itself is converted into an optical output, and in the latter, a part of the secondary current waveform is converted into an optical output, but it is saturated. The pulse width is obtained by setting the current level, that is, by setting one point.
したがって本考案の目的は、電流の大きさをパルス発生
頻度に変換することによって、上記した従来技術の欠点
を解消し、計測レンジが大きくとれて、しかも精度良く
計測できる電流計測装置を提供することにある。Therefore, an object of the present invention is to solve the above-mentioned drawbacks of the prior art by converting the magnitude of the current into the pulse generation frequency, to provide a current measuring device which has a large measuring range and can be accurately measured. It is in.
［問題点を解決するための手段］ 本考案の電流計測装置は、１次電流によって変成器の２
次側に発生する２次電流を整流してコンデンサに充電す
る充電回路と、コンデンサに充電された充電量が所定値
に達する毎に放電して電流半波当りの放電回数を１次電
流の大きさに比例させる放電回路とを備えている。[Means for Solving Problems] The current measuring device of the present invention uses a primary current to convert a transformer
A charging circuit that rectifies the secondary current generated on the secondary side and charges the capacitor, and discharges each time the amount of charge charged in the capacitor reaches a predetermined value, and the number of discharges per half current is the magnitude of the primary current. And a discharge circuit that is proportional to the height.
また、放電回路の放電電流で発光する発光手段と、発光
手段の発光回数を計数して１次電流を計測する計測手段
とを備えている。Further, it is provided with a light emitting means that emits light by the discharge current of the discharge circuit, and a measuring means that counts the number of times the light emitting means emits light and measures the primary current.
［作用］ 高調波やノイズを重畳とした１次電流が流れても、変成
器の２次巻線抵抗と充電回路のコンデンサとによってノ
イズは積分された形で、また高調波はコンデンサによっ
てバイパスされた形で上記１次電流がコンデンサに充電
される。このため、高調波やノイズは吸収ないし平滑化
されて、コンデンサには１次電流の基本波成分のみが充
電される。[Operation] Even if the primary current with superimposed harmonics and noise flows, the noise is integrated by the secondary winding resistance of the transformer and the capacitor of the charging circuit, and the harmonics are bypassed by the capacitor. The primary current is charged into the capacitor in a different form. Therefore, harmonics and noise are absorbed or smoothed, and the capacitor is charged with only the fundamental wave component of the primary current.
一方、充電回路のコンデンサに充電された充電量の、放
電回路における放電時間を短くすると、電流半波当りの
放電回数が増加して、１次電流の大きさが、より多い発
光回数で計測される。On the other hand, if the discharge time of the discharge circuit of the charge amount charged in the capacitor of the charge circuit is shortened, the number of discharges per half current of the current increases, and the magnitude of the primary current is measured with a larger number of light emission. It
［実施例］ 本考案の実施例を第１図〜第５図を用いて説明する。[Embodiment] An embodiment of the present invention will be described with reference to FIGS.
第１図は本考案の電流計測装置を送電線故障区間標定シ
ステムの計測装置に適用した第１実施例を示す。変成器
CT内を架空地線１が貫通して１次側を構成し、この１次
側架空地線１に流れる１次電流Ｉ0で変成器CTを励磁す
る。FIG. 1 shows a first embodiment in which the current measuring device of the present invention is applied to a measuring device of a transmission line fault section locating system. Transformer
The overhead ground wire 1 penetrates through the CT to form the primary side, and the transformer CT is excited by the primary current I 0 flowing through the primary side overhead ground wire 1.
変成器CTの２次側には充電回路１０と放電回路１１とが
接続されている。充電回路１０はダイオードＤとコンデ
ンサＣ1とで構成され、コンデンサＣ1と変成器CTの２次
巻線抵抗とから決まる時定数でコンデンサＣ1に２次電
流の正の半波成分が充電される。A charging circuit 10 and a discharging circuit 11 are connected to the secondary side of the transformer CT. The charging circuit 10 is constituted by a diode D and a capacitor C 1, the positive half-wave component of the secondary current to the capacitor C 1 is charged with a time constant determined from the capacitor C 1 and secondary winding resistance of transformer CT It
放電回路１１は充電回路１０のコンデンサＣ1に並列に
接続され、抵抗Ｒ1を直列に挿入した発光ダイオードLED
と抵抗Ｒ2とからなる並列抵抗回路に、サイリスタSCRを
直列接続して構成されている。放電回路１１の時定数は
コンデンサＣ１と並列抵抗Ｒ1Ｒ2とで決まる。また、
抵抗Ｒ1とＲ2とは、並列抵抗Ｒ1Ｒ2に流れる放電電流
をＲ1とＲ2との比に応じて分流することができ、抵抗Ｒ
1に流れる電流が発光ダイオードLEDの発光電流となるよ
うに構成されている。サイリスタSCRのカソードと接地
間に直列接続したリアクタＬ及びコンデンサＣ2は、適
当な電圧のときにサイリスタSCRをOFFにするために共振
素子である。サイリスタSCRのゲートには、アノードと
接地間に直列接続されたツエナーダイオードZDと抵抗Ｒ
3との接続点がつながれている。The discharging circuit 11 is connected in parallel to the capacitor C 1 of the charging circuit 10 and has a resistor R 1 inserted in series to form a light emitting diode LED.
A thyristor SCR is connected in series to a parallel resistance circuit composed of a resistor R 2 and a resistor R 2 . The time constant of the discharge circuit 11 is determined by the capacitor C1 and the parallel resistance R 1 R 2 . Also,
The resistors R 1 and R 2 can divide the discharge current flowing through the parallel resistor R 1 R 2 according to the ratio of R 1 and R 2, and
The current flowing through 1 is configured to be the light emitting current of the light emitting diode LED. The reactor L and the capacitor C 2 connected in series between the cathode of the thyristor SCR and the ground are resonant elements for turning off the thyristor SCR when the voltage is appropriate. The gate of the thyristor SCR has a Zener diode ZD and a resistor R connected in series between the anode and ground.
The connection point with 3 is connected.
上記発光ダイオードLEDには光ファイバ複合架空地線の
光ファイバ２が接続され、光ファイバ２の遠端部にはダ
イオードLEDの発光信号を電気信号に変換して発光信号
数をカウントする光／電気変換回路(O/E)3が接続されて
いる。The above-mentioned light emitting diode LED is connected to an optical fiber 2 of an optical fiber composite ground wire, and an optical / electrical device for converting the light emitting signal of the diode LED into an electric signal and counting the number of light emitting signals at the far end of the optical fiber The conversion circuit (O / E) 3 is connected.
次に第１図に示す回路の動作について説明する。電線１
に電流Ｉ0が流れると、ダイオードＤの導通方向の半波
成分のときコンデンサＣ1が充電される。コンデンサＣ1
に充電される充電電圧がツエナーダイオードZDの動作電
圧を超えると、サイリスタSCRのゲートにトリガ電流が
流れるため、サイリスタSCRがONする。サイリスタSCRの
ONによってコンデンサＣ1に充電された電荷が並列接続
された抵抗Ｒ1，Ｒ2を介して放電され、抵抗Ｒ1に直列
接続されているLEDをパルス発光させる。このLEDのパル
ス光は光ファイバ２を介してO/E3に伝送される。Next, the operation of the circuit shown in FIG. 1 will be described. Electric wire 1
When a current I 0 flows through the capacitor C 1, the capacitor C 1 is charged when the diode D has a half-wave component in the conduction direction. Capacitor C 1
When the charging voltage charged to the thyristor exceeds the operating voltage of the Zener diode ZD, a trigger current flows in the gate of the thyristor SCR, and the thyristor SCR turns on. Thyristor SCR
When turned on, the electric charge charged in the capacitor C 1 is discharged through the resistors R 1 and R 2 connected in parallel, and the LEDs connected in series to the resistor R 1 are pulsed to emit light. The pulsed light of this LED is transmitted to O / E3 via the optical fiber 2.
放電回路の放電が停止すると、コンデンサＣ1は再び充
電を開始し、この充電電圧がツエナーダイオードZDの動
作電圧に達すると再放電する。この状況を図示したもの
が第２図であり、１次電流Ｉ0が正のときで、その大き
さが大きい程放電パルスＰの数が増大する。When the discharging circuit stops discharging, the capacitor C 1 starts charging again, and when the charging voltage reaches the operating voltage of the Zener diode ZD, the capacitor C 1 is discharged again. FIG. 2 illustrates this situation. When the primary current I 0 is positive and the magnitude thereof is large, the number of discharge pulses P increases.
ところで、１次電流半波当りの光パルス数が多ければ多
いほど検出精度が上がる。したがって、第１図に示すコ
ンデンサＣ1と並列抵抗Ｒ1Ｒ2とで決まる時定数を小
さく選定し、光パルス幅を狭くすることによってダイナ
ミックレンジを大きくとることができる。By the way, as the number of light pulses per half wave of the primary current increases, the detection accuracy increases. Therefore, the dynamic range can be widened by selecting a small time constant determined by the capacitor C 1 and the parallel resistance R 1 R 2 shown in FIG. 1 and narrowing the optical pulse width.
また、並列抵抗Ｒ1Ｒ2の値を変えないで抵抗Ｒ1とＲ2
との分流比を任意に変えることができる。従って、発光
ダイオードLEDに流れる電流を所望の値に設定すること
ができる。Also, without changing the value of the parallel resistance R 1 R 2 , the resistances R 1 and R 2
The diversion ratio of and can be changed arbitrarily. Therefore, the current flowing through the light emitting diode LED can be set to a desired value.
この半サイクル中のパルス数Ｎをカウントし、一次電流
Ｉ0との関係を示したものが第３図となる。したがっ
て、パルス数を第１図中のO/E3側でカウントすると、１
次電流Ｉ0の大きさを計測できる。The number N of pulses in this half cycle is counted, and the relationship with the primary current I 0 is shown in FIG. Therefore, if the number of pulses is counted on the O / E3 side in FIG.
The magnitude of the next current I 0 can be measured.
この場合において、ツエナーダイオードZDを用いてコン
デンサＣ1の放電電圧を一定としているため、光出力強
度は１次電流に無関係に一定となり、したがって光出力
強度と光受信感度の差分に相当する長さまで光ファイバ
長を長くできる。このことは、特に鉄塔間の距離が大き
い場合に有効となる。In this case, since the discharge voltage of the capacitor C 1 is made constant by using the Zener diode ZD, the light output intensity becomes constant irrespective of the primary current, so that the length corresponding to the difference between the light output intensity and the light receiving sensitivity is reached. The optical fiber length can be increased. This is particularly effective when the distance between steel towers is large.
なお、変成器から発光ダイードまで無電源で動作するた
め、電源を設ける必要もない。Since the transformer and the light emitting diode operate with no power source, it is not necessary to provide a power source.
上記した第１図の第１実施例は電気信号の半波のみの情
報を伝送する方式であるが、第４図は両波とも電流値と
して伝送するための第２実施例を示す回路図である。The above-mentioned first embodiment of FIG. 1 is a system for transmitting information of only half wave of electric signal, but FIG. 4 is a circuit diagram showing a second embodiment for transmitting both waves as a current value. is there.
第１図と異なる点は、両波信号を伝送するために半波整
流用のダイオードＤを、ダイオードＤ1〜Ｄ4からなるブ
リッジ回路にした点と、片極性のときのみ補助サイリス
タSCR2をONにして発光ダイオードLEDに流れる電流を変
えるために、絶縁変圧器PT及び整流ダイードＤ5を設け
た点であり、他は基本的に同一構成となっている。1 is different from FIG. 1 in that the diode D for half-wave rectification is a bridge circuit composed of the diodes D 1 to D 4 for transmitting the both-wave signal, and the auxiliary thyristor SCR 2 is provided only in the case of one polarity. The point is that an insulating transformer PT and a rectifying diode D 5 are provided in order to turn on and change the current flowing through the light emitting diode LED, and the other configurations are basically the same.
補助サイリスタSCR2がONするときは、これに直列接続さ
れた限流抵抗Ｒ4が限流抵抗Ｒ1と並列になって、また補
助サイリスタSCR2がOFFのときは限流抵抗Ｒ1単独となっ
て、発光ダイオードLEDの電流を変えることにより、電
流の極性が分かるようになっている。第５図に示すよう
に、例えばプラス極性のときの光パルス強度をマイナス
極性のときの光パルス強度よりも大きくしておけば、O/
E3内で電流の極性も識別できることになる。When the auxiliary thyristor SCR 2 is turned on, the current limiting resistor R 4 connected in series with it is in parallel with the current limiting resistor R 1, and when the auxiliary thyristor SCR 2 is turned off, the current limiting resistor R 1 is independent. Then, by changing the current of the light emitting diode LED, the polarity of the current can be known. As shown in FIG. 5, for example, if the light pulse intensity in the positive polarity is set to be larger than the light pulse intensity in the negative polarity, O /
The polarity of the current can also be identified in E3.
［考案の効果］ 本考案によれば次の効果がある。[Effects of the Invention] The present invention has the following effects.
(1)充電回路を設けて、１次電流半波当りの発光回数を
一次電流の積分値に比例するようにしたので、１次電流
に高調波やノイズが重畳していても、これらに影響され
ない。(1) Since a charging circuit is provided so that the number of times of light emission per half-wave of the primary current is proportional to the integral value of the primary current, even if harmonics or noise are superposed on the primary current, these will be affected. Not done.
(2)放電回路を設けて、１次電流の大きさを放電回数に
変換するようにしたので、放電時間を短くすることによ
って電流計測レンジを大幅に拡大できる。(2) Since the discharge circuit is provided to convert the magnitude of the primary current into the number of discharges, the current measurement range can be greatly expanded by shortening the discharge time.
第１図は本考案に係る電流計測装置の第１実施例を示す
回路図、第２図は同じく動作説明図、第３図は同じく回
路特性図、第４図は本考案の第２実施例を示す回路図、
第５図は同じく動作説明図である。 図中、３は光電気変換器（計測手段）、１０は充電回
路、１１は放電回路、Ｉ0は１次電流、CTは変成器、Ｄ
は整流用ダイオード、Ｃ1はコンデンサ、LEDは発光ダイ
オード、SCRはサイリスタ（スイッチ手段）、ZDはツエ
ナーダイオード（充電量検知手段）、Ｒ1，Ｒ2は放電時
定数を決める抵抗である。FIG. 1 is a circuit diagram showing a first embodiment of a current measuring device according to the present invention, FIG. 2 is an operation explanatory diagram thereof, FIG. 3 is a circuit characteristic diagram thereof, and FIG. 4 is a second embodiment of the present invention. Circuit diagram,
FIG. 5 is the same operation explanatory diagram. In the figure, 3 is a photoelectric converter (measuring means), 10 is a charging circuit, 11 is a discharging circuit, I 0 is a primary current, CT is a transformer, and D is D.
Is a rectifying diode, C 1 is a capacitor, LED is a light emitting diode, SCR is a thyristor (switch means), ZD is a zener diode (charge amount detection means), and R 1 and R 2 are resistors that determine the discharge time constant.
Claims (4)
る２次電流を整流してコンデンサに充電する充電回路
と、コンデンサに充電された充電量が所定値に達する毎
に放電して電流半波当りの放電回数を１次電流の大きさ
に比例させる放電回路と、この放電回路を構成し上記充
電回路のコンデンサとともに放電の時定数を決める２個
の並列抵抗からなる並列抵抗回路と、この並列抵抗回路
の一方の抵抗に接続され放電電流の一部で発光する発光
手段と、発光手段の発光回数を計数して１次電流を計測
する計測手段とを備えたことを特徴とする電流計測装
置。1. A charging circuit for rectifying a secondary current generated on the secondary side of a transformer by a primary current to charge a capacitor; and a discharge circuit that discharges each time the amount of charge charged in the capacitor reaches a predetermined value. A discharge circuit that makes the number of discharges per half-wave of current proportional to the magnitude of the primary current, and a parallel resistance circuit that is composed of two parallel resistors that constitute this discharge circuit and that determines the discharge time constant together with the capacitor of the charging circuit. And a light emitting means that is connected to one of the resistors of the parallel resistance circuit and emits light with a part of the discharge current, and a measuring means that counts the number of times the light emitting means emits light and measures the primary current. Current measuring device.
ンデンサに充電する充電回路であることを特徴とする実
用新案登録請求の範囲第１項記載の装置。2. The device according to claim 1, wherein the charging circuit is a charging circuit for half-wave rectifying a secondary current to charge a capacitor.
ンデンサに充電する充電回路であることを特徴とする実
用新案登録請求の範囲第１項記載の装置。3. The device according to claim 1, wherein the charging circuit is a charging circuit for full-wave rectifying the secondary current to charge the capacitor.
に接続された上記並列抵抗回路と、この並列抵抗回路の
反対側にアノードを接続されたサイリスタと、上記コン
デンサの充電電圧が所定値に達すると上記サイリスタの
ゲートをトリガするツェナダイオード及び抵抗と、上記
サイリスタのカソードと上記コンデンサの接地側との間
に設けられ上記サイリスタをOFFするためのリアクタ及
びコンデンサとから構成されていることを特徴とする実
用新案登録請求の範囲第１項，第２項又は第３項記載の
装置。4. The discharging circuit comprises the parallel resistance circuit connected to the charging side of the capacitor, a thyristor having an anode connected to the opposite side of the parallel resistance circuit, and the charging voltage of the capacitor reaches a predetermined value. When it reaches, it is composed of a Zener diode and a resistor that triggers the gate of the thyristor, and a reactor and a capacitor that are provided between the cathode of the thyristor and the ground side of the capacitor to turn off the thyristor. The device according to claim 1, 2, or 3 of the utility model registration claim.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987105322U JPH0620140Y2 (en) | 1987-07-10 | 1987-07-10 | Current measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987105322U JPH0620140Y2 (en) | 1987-07-10 | 1987-07-10 | Current measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6410667U JPS6410667U (en) | 1989-01-20 |
| JPH0620140Y2 true JPH0620140Y2 (en) | 1994-05-25 |
Family
ID=31337829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1987105322U Expired - Lifetime JPH0620140Y2 (en) | 1987-07-10 | 1987-07-10 | Current measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0620140Y2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2854352B2 (en) * | 1989-12-05 | 1999-02-03 | 株式会社サンコーシャ | Voltage-pulse converter and voltage measuring device using the same |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5663264A (en) * | 1979-10-29 | 1981-05-29 | Furukawa Electric Co Ltd:The | Current detecting method |
-
1987
- 1987-07-10 JP JP1987105322U patent/JPH0620140Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6410667U (en) | 1989-01-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0620140Y2 (en) | Current measuring device | |
| CA1098585A (en) | Monitoring system for high-voltage supply | |
| GB2339295A (en) | Instrument for measuring alternating current | |
| US6366484B1 (en) | Cross current sensing in power conversion | |
| JPH0642214Y2 (en) | Current measuring device | |
| US20230062534A1 (en) | Power control device, dc-dc converter, and ac-dc converter | |
| WO2021204569A1 (en) | Energy metering and surge current detection | |
| JP3328728B2 (en) | Motor power detection device and overload protection device | |
| JPS6325338Y2 (en) | ||
| SU836752A1 (en) | Current relative pulse duration transmitter | |
| JPH0712938Y2 (en) | Transmission line fault current detector | |
| JPH0664120B2 (en) | Method for measuring dv / dt tolerance of thyristor | |
| JPH07213060A (en) | Switching power unit | |
| SU595677A1 (en) | Device for measuring current in converter rectifier diode circuit | |
| SU1069057A1 (en) | Device for checking current of rectifier converter | |
| JPS552302A (en) | High-tension generator | |
| JPH049579Y2 (en) | ||
| JPH0424761Y2 (en) | ||
| JPH0736443Y2 (en) | Optical current transformer for ground fault detection | |
| JPS5830232Y2 (en) | pulse seizatsuonkenshiyutsu warmer | |
| JPH0562955B2 (en) | ||
| RU2031978C1 (en) | Cathode station control apparatus | |
| SU1527672A1 (en) | Dc transformer | |
| RU2093838C1 (en) | Current measuring transducer | |
| SU535688A1 (en) | Constant voltage converter |