JP3833519B2

JP3833519B2 - Vacuum circuit breaker

Info

Publication number: JP3833519B2
Application number: JP2001340261A
Authority: JP
Inventors: 功奥富; 敦史山本; 貴史草野; 経世関; 三孝本間; 淑子南
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2001-11-06
Filing date: 2001-11-06
Publication date: 2006-10-11
Anticipated expiration: 2021-11-06
Also published as: JP2003147456A

Description

【０００１】
【発明の属する技術分野】
この発明は、すぐれた遮断特性と再点弧特性とを両立させた接点を備えた真空バルブより成る真空遮断器に関する。
【０００２】
【従来の技術】
一般に、真空バルブより成る真空遮断器において、真空中でのアークの拡散性を利用して高真空中で電流遮断を行わせる真空バルブの接点は、対向する固定、可動の２つの接点から構成されている。
【０００３】
図７に示す如く、絶縁容器１０１の両端開口部を蓋体１０２ａ、１０２ｂにより閉塞した真空容器１０３内に、一対の接点１０４、１０５を対向させて設けると共に、これらを、前記蓋体１０２ａ、１０２ｂを貫通させて真空容器１０３内に挿入された通電軸１０６、１０７の端部にそれぞれ装着し、その一方の通電軸１０７を図示しない操作機構により軸方向に移動可能として、前記一方の接点である固定接点１０４に対して、他方の接点である可動接点１０５を接触または開離出来るようにしてある。この場合、蓋体１０２ｂと通電軸１０７との間には、真空容器１０３内を真空気密に保持しかつ通電軸１０７の軸方向への移動を可能とするベローズ１０８が設けられる。なお図中１０９は、前記各接点１０４、１０５および通電軸１０６、１０７を包囲する如く設けられたシールドである。
【０００４】
上記真空遮断器は、通常両接点１０４、１０５が接触し通電状態となる。この状態からの動作により通電軸１０７が図中矢印Ｍ方向に移動すると、可動接点１０５が固定接点１０４から開離し、両接点間にはアークが発生する。このアークは陰極例えば可動接点１０５側からの金属蒸気の発生により維持され、電流がゼロ点（零点）に達すると金属蒸気の発生が止まってアークが維持できなくなり、遮断が完了する。
【０００５】
ところで、上記両接点１０４、１０５間に発生するアークは、遮断電流が大きいとアーク自身により生じた磁場と外部回路の作る磁場との相互作用により著しく不安定な状態となる。その結果、アークは接点面上を移動し（接点が電極に取り付けられ一体化している時には、アークは電極面上にも移動している場合もある）、接点の端部或いは周辺部に片寄り、その部分を局部的に過熱し、多量の金属蒸気を放出させて、真空容器１０３内の真空度を低下させる。その結果、真空遮断器の遮断性能は低下する。これらは金属組織などで代表される接点の状態に依存することが多い。
【０００６】
図８は、一対の接点４１、５１を対向させて設けると共に、接点４１の背面には平板型電極４０、接点５１の背面には平板型電極５０をそれぞれ装着した真空バルブである。また接点４１の背面にはコイル電極４０、接点５１の背面にはコイル電極５０をそれぞれ装着することもできる。
【０００７】
一般に真空遮断器では、大電流断性能、耐電圧性能、耐溶着性能の基本的３要件の他に再点弧現象の発生の抑制が重要な要件となっている。
【０００８】
しかしながら、これらの要件の中には相反するものがある関係上、単一の金属種によって総ての要件を満足させることは不可能である。この為、実用されている多くの接点材料に於いては、不足する性能を相互に補うような２種以上の元素を組合せることによって、例えば大電流用、高耐圧用などのように特定の用途に合った接点材料の選択採用が行われ、それなりに優れた特性を持つ真空バルブが開発されているが、それでも一部の機能を犠牲にして対応している製品が多い。さらに強まる要求を充分満足する真空バルブは未だ得られていないのが実情である。
【０００９】
例えば、大電流遮断性を目的とした接点として、Ｃｒを５０重量％（ｗｔ％）程度含有させたＣｕ−Ｃｒ合金（特公昭４５-３５１０１号）が知られている。この合金は、Ｃｒ自体がＣｕと略同等の蒸気圧特性を保持し、かつ強力なガスのゲッタ作用を示す等の効果で高電圧大電流断性を実現し、高耐圧特性と大容量遮断とを両立させ得る接点として多用されている。
【００１０】
この合金は、活性度の高いＣｒを使用していることから、原料粉の選択、不純物の混入、雰囲気の管理などに十分に配慮しながら接点素材を製造（焼結工程など）したり、接点素材から接点片へと加工に配慮したりしながら接点製品としているが、再点弧の発生が引金となって遮断性能を低下させる場合が見られ、その改善が望まれている。
【００１１】
【発明が解決しようとする課題】
ＣｕＣｒ接点は、両者の高温度での蒸気圧特性が近似していることなどが主因となって、遮断した後でも接点表面は比較的平滑な損傷特性を示し、安定した電気特性を発揮している。
【００１２】
近年では一層の大電流遮断やより高電圧が印加される可能性のある回路への適応が日常的に行われる結果、接点として加工した新品時の表面状態、電流遮断後の接点表面の損傷状態などによっては、次の定常電流を開閉した時に、接触抵抗の異常上昇や温度の異常上昇を引き起こす原因となり、あるいは耐電圧不良を示し再点弧発生の一因となっている。
【００１３】
しかし、接点の表面状態を管理しても完全には再点弧発生を抑制することが出来ず、十分な電流遮断特性が得られていないのが現実である。
【００１４】
更に、例えばＣｕＣｒ合金の再点弧特性と遮断特性の安定化には、接点材料の組成、成分量（Ｃｒ量）、組織形態（粒度、粒度分布、偏析の程度、合金中に存在する空孔の程度）、ガス量および接点の表面形態に強く依存することが判明した。しかしこれらの最適化を進めているにも拘らず、上述した近年の適応状況では、まだ再点弧特性にはばらつきが見られ、特に再点弧特性のより一層の安定化と遮断特性との両特性を兼備した真空遮断器が必要となって来た。
【００１５】
この発明の目的は、再点弧特性と遮断特性とを両立させた真空遮断器を提供することにある。
【００１６】
【課題を解決するための手段】
本発明に係る真空遮断器は、真空容器と、ベローズと、通電軸と、対向する一対の接点とを備えた真空遮断器において、接点は１０〜８５重量％のＣｕより成る導電性成分と、残部が０．１〜１５０μｍの平均粒子直径を持つ９０〜１５重量％のＣｒより成る耐弧性成分とを含有するＣｕ−Ｃｒ系接点合金から成り、合金中のＣｕマトリックスにおける酸性溶液に溶解しないＣｕ化合物である酸非溶解性Ｃｕ化合物の量が１０ｐｐｍ〜１０００ｐｐｍであることを特徴とする。
【００１７】
このような構成により、再点弧特性と遮断特性とを両立させることができる。
【００１８】
すなわち、ＣｕＣｒ接点中の酸非溶解性Ｃｕ化合物の量が１０００ｐｐｍを越えると、再点弧の発生頻度が大となると共に素材毎に酸非溶解性Ｃｕ化合物の分布にばらつきが見られ、その結果再点弧の発生にも素材毎にばらつきが見られ、再点弧が不安定化する。
【００１９】
ＣｕＣｒ接点中の酸非溶解性Ｃｕ化合物の量を１０ｐｐｍ未満とすることは技術的には可能であるが、経済性の観点から得策ではない。
【００２０】
なお、Ｃｕ量が８５重量％を越えると、電流の遮断時に耐アーク性が劣り遮断後の接点表面は著しい荒れを示し、この荒れが再点弧発生の原因の１つとなる。Ｃｕ量が１０重量％未満では、低い導電性の為、十分な遮断特性が得られないと共に、接触抵抗特性、温度上昇特性も劣化する。
【００２１】
また、耐弧性成分の平均粒子直径は、全Ｃｒ粒子のうち０．１〜１５０μｍの範囲のＣｒ粒子が少なくとも７５容積％を占める時、安定した再点弧特性を発揮する。
【００２２】
Ｃｒ粒子の平均粒子径を０．１μｍ未満とすることは、製造技術的観点からコストが著しく高くなり、供給性に難点がある。１５０μｍを越えると、仕上げ加工した接点表面には、Ｃｒ粒子とＣｕ相界面に引っかき状の傷を残し平滑で均一な状態が得難く、再点弧特性が大きく低下する。
【００２３】
【発明の実施の形態】
以下、本発明の実施形態について詳細に説明する。
【００２４】
研究によれば、電流を遮断した直後の接点面は主としてアーク熱によって極めて高温度になり、溶融した接点面からは多量の気体状成分や固体状成分が電極空間に放出される。このうち気体状成分が電極間に所定時間以上停滞していると、真空の持つ、優れた絶縁性は破壊される。従って電極間の絶縁耐力を維持するには、接点面から放出される気体状成分の絶対量をあらかじめ極少にしておくことや、放出された気体状成分を速やかに電極間以外に拡散除去することも重要である。
【００２５】
すなわち、接点の表面或いは接点内部に存在する物質（上述の気体状成分や固体状成分）内で、アーク熱によって簡単に分解あるいは除去される様な物質の場合には、遮断前の段階（アークによって接点が昇温して行く前）や昇温過程の極く初期の段階に電極空間に移動し、再点弧発生の直接的原因となる確率は低いことが観察された。
【００２６】
逆に簡単に分解あるいは除去されない物質の場合には、遮断が完了しても分解あるいは除去が進行し電極空間に移動し、再点弧発生の重要な一因となることが観察された。
【００２７】
前記した物質が分解される過程で生成されるガス（気体）の場合では、質量数の大きい成分ほど拡散速度が遅く電極空間に残存し易く、真空度の回復が遅れる傾向にあり、その結果絶縁破壊を誘発する。
【００２８】
ここで、接点の表面或いは接点内部に存在する物質には、アーク熱やジュール熱で簡単に排除可能な物質と、簡単には排除不可能な物質の２種類の存在が考えられる。この内で特に後者の物質の取扱いが再点弧に対して重要となる。すなわち電流を遮断する前の段階で（或いは接点が昇温して行く途中の極く初期の段階で）、簡単に分解あるいは電極空間に放出・除去出来ない物質を、低減化することが重要となる。その為には、簡単に分解あるいは除去出来ない物質がどの程度の量存在するかを実際の電流を遮断することなくどう定量化するかも重要となる。
【００２９】
接点の総てを完全に蒸気状態にまで加熱すれば、その時に放出される表面ガス量や内蔵ガス量を総て捕捉することが出来るが、接点の総てを完全に蒸気状態にまで加熱する事は不可能であって、実際には融解中に分解しない物質が存在するので、表面或いは接点内部に存在する物質の総量を捕捉することは出来ないのが実情である。
【００３０】
ＣｕＣｒ合金を塩酸、硝酸などの酸類によって溶解すると、酸に溶解して除去される成分と、これとは別に酸に溶解しない非溶解物である酸非溶解性Ｃｕ化合物（ｙ）が残存する。
【００３１】
前者の酸に溶解し除去可能な成分は、アーク熱を受けた時点で接点表面へ拡散し易く、除去され易い成分に相当する。
【００３２】
これに対して、後者の酸に非溶解で除去不可能な成分は、Ｃｕ酸化物やＣｕ窒化物などＣｕ化合物として、接点表面部や接点内部に固形体として存在し、これらは簡単には分解あるいは除去され難い物質に相当し、再点弧抑制に対して重要な意味を持つ。
【００３３】
前記接点表面部分に存在する酸非溶解物（ｙ）は、アークを受けた時、分解して瞬間的に多量のガスを放出したり、分解生成物を放出したりして、これが再点弧発生の一因となる。一方の接点内部に存在する酸非溶解物（ｙ）も、アークによって分解して同様に多量のガスを放出したり、分解生成物を放出したりして、同様に再点弧発生の一因となる。接点表面への拡散が遅れる為、遮断後或る時間経過後に見られる再点弧の一因となる。
【００３４】
（実験１）：発明者らの実験によれば、極微少の酸非溶解性Ｃｕを接点中に存在させる一つの手段として、有機溶媒中に懸濁させたサブミクロン級のＣｕ酸化物を被着させたＣｒスケルトンを製造し、このＣｒスケルトンの空隙中にＣｕを溶浸させる溶浸法によって、極く微量で微細酸化Ｃｕ（銅）を内部に持つＣｕＣｒ合金を製造した。有機溶媒中に懸濁させる酸化Ｃｕの量を調整することによって、ＣｕＣｒ合金中の微細酸化Ｃｕの量を調製することは容易である。
【００３５】
同じく他の手段として、有機溶媒中に懸濁させたサブミクロン級の酸化Ｃｕを被着させたＣｒ粉とＣｕ粉とを固相焼結してＣｕＣｒ合金を製造した。
【００３６】
いずれの製造法によって得たＣｕＣｒ合金でも、酸化Ｃｕの量が多量の場合には、再点弧の発生頻度が大となるのに対して、酸化Ｃｕの量が少量の場合には、再点弧の発生頻度が極めて少ない傾向にある。この酸非溶解物（ｙ）を分析すると、その中には特に酸非溶解性Ｃｕ化合物（ｙ）の存在が確認される。
【００３７】
（実験２）：発明者らの他の観察によれば、接点材料中には、極く微細な析出物が存在する場合と、析出物の無い場合とが見られる。
【００３８】
実際の真空遮断器に於いて、再点弧発生頻度の高い真空バルブに搭載した接点を更に微視的に観察すると、極く微細な析出物、介在物（いずれも酸に非溶解）が確認され、この場合の酸に非溶解の物質（ｙ）中には、Ｃｕ化合物が一定量以上に存在していることを確認した。
【００３９】
これに対して、再点弧発生頻度の少ない真空バルブに搭載した接点を更に微視的に観察すると、微細析出物、介在物中（いずれも酸に非溶解）にはＣｕ化合物が少ない傾向にあった。
【００４０】
従ってこの実験から、酸非溶解性物質の存在とその中のＣｕ化合物（ｙ）の量とが、再点弧特性と深く関わっていることが示唆される。
【００４１】
真空バルブの再点弧特性、遮断特性の安定化には、一般的には接点材料の組成、成分量の変動、ガス量、組織形態（粒度、粒度分布、偏析の程度、合金中に存在する空孔の程度）など、および接点の表面形態に強く依存するが、特に再点弧特性のより一層の安定化には、上記に加えてＣｕＣｒ合金を酸溶液によって溶解した後に、溶解せずに溶液中に残存している酸非溶解性Ｃｕ化合物（ｙ）の量が深く関与する。
【００４２】
以下に、本発明を実施例と比較例とで詳細に説明する。評価条件と評価結果を図１〜図６に示す。
【００４３】
（１）再点弧特性
直径３０ｍｍ、厚さ５ｍｍの円板状接点片を、ディマウンタブル型真空バルブに装着し、２４ｋｖ×５００Ａの回路を２０００回遮断した時の再点弧発生頻度を測定した。
【００４４】
尚、結果は再点弧頻度を下記の様に表示した。
【００４５】
即ち、実施例２の発生数を１．０とした時の倍率が、０．１未満を評価（Ａ）、０．１〜０．８を評価（Ｂ）、０．８〜１．２を評価（Ｃ）、１．２〜１．５を評価（Ｄ）、１．５〜１０を評価（Ｘ）、１０〜１００を評価（Ｙ）、１００以上を評価（Ｚ）とした。
【００４６】
なお、評価（Ａ）〜（Ｄ）を「合格」、評価（Ｘ）〜（Ｚ）を「不良」の目安とした。
【００４７】
（２）遮断特性
直径７０ｍｍの接点を装着した遮断テスト用実験バルブを開閉装置に取り付けると共に、ベーキング、電圧エージング等を与えた後、２４ｋｖ、５０Ｈｚの回路に接続し、電流をほぼ１ｋＡずつ増加しながら遮断限界を真空バルブ3本につき評価した。尚、数値は実施例２の値を１．０とした時の比較値を、バラツキ幅を持って示した。
【００４８】
（３）遮断テスト用実験バルブの組立ての概要
遮断テスト用実験バルブの組立ての概要を示す。端面の平均表面粗さを約１．５μｍに研磨したセラミックス製絶縁容器（主成分：ＡＬ₂Ｏ₃）を用意し、このセラミックス製絶縁容器については、組立て前に１６００℃の前加熱処理を施した。封着金具として、板厚さ２ｍｍの４２％Ｎｉ−Ｆe合金を用意した。ロウ材として、厚さ０．１ｍｍの７２％Ａｇ−Ｃｕ合金板を用意した。上記用意した各部材を被接合物間（セラミックス製絶縁容器の端面と封着金具）に気密封着接合が可能なように配置して、５×１０^-4Ｐａの真空雰囲気で封着金具とセラミックス製絶縁容器との気密封着工程に供した。
【００４９】
（４）接点合金中の酸非溶解性Ｃｕ化合物（ｙ）の定量
接点素材中に含有される合金中の酸非溶解性Ｃｕの定量は、例えば下記の方法で実施した。微細化したＣｕＣｒ接点に硝酸を加えた後、ろ液（Ｃｕ相）と沈殿物Ａとに分別する。この場合のろ液（Ｃｕ相）は、酸溶解性Ｃｕ成分(ｘ)に相当する。沈殿物Ａについて酸溶解溶解によって、ろ液（Ｃｒ）と沈殿物Ｂとに分別する。沈殿物ＡをＩＣＰ−ＡＥＳなどの分析装置で定量することによって酸非溶解物質（ｙ）を知る。
【００５０】
（実施例１〜４、比較例１〜２）
本発明では、再点弧特性、遮断特性と、接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）との関係が重要である。
【００５１】
酸に非溶解のＣｕ化合物（ｙ）の量は以下の条件で定量化した。
【００５２】
代表接点としてＣｕ−２５％Ｃｒ合金を選択し、この接点素材から約１０ｇｒ．を採取した。例えば１００℃で３Ｎ（規定）のＨＮＯ₃中で約１０分間加熱分解の後、これをろ過し、ろ液Ａと沈殿物Ａとに分別する。
【００５３】
ろ液Ａ中には、ＨＮＯ₃に溶解したＣｕ（Ｃｕ²⁺）と、ＨＮＯ₃に溶解した微量のＣｒとが存在する。このろ液Ａ中に溶解しているＣｕ（ｘ）の量、Ｃｒ（ｂ）の量をＩＣＰ−ＡＥＳなどで定量する。なお、（ｘ）の値は、焼結後の接点素材中のＣｕ相に相当する。
【００５４】
沈殿物Ａには、ＨＮＯ₃に溶解しないＣｕ（ｙ）と、ＨＮＯ₃に溶解しないＣｒ（ｃ）とが存在する。この沈殿物Ａ中のＣｕ（ｙ）の量、Ｃｒ（ｃ）の量をＩＣＰ−ＡＥＳなどで定量する。
【００５５】
以上の分析によって、本発明で重要な酸性溶液に溶解するＣｒ（ｂ）の量と酸性溶液に溶解しないＣｕ（ｙ）の量を容易に知ることが出来る。更に補助知見として酸性溶液に溶解するＣｕ（ｘ）の量と酸性溶液に溶解しないＣｒ（ｃ）の量も容易に知ることが出来る。
【００５６】
参考として、沈殿物Ａを６ＮのＨＣｌによって加熱分解（１００℃で３０分間）した後、ろ過し、ろ液Ｂ（Ｃｒ³⁺）と沈殿物Ｂとに分別する。
【００５７】
ここでろ液Ｂ（Ｃｒ³⁺）は、接点製造時に原料として使用している０．１〜１５０μｍのＣｒ粒子（ａ）とほぼ一致する。（ａ）の値は、理論的には、（ｂ）と（ｃ）との和と、（分析操作時の損失）と（焼結工程など接点製造時の損失）との和との合計である。
【００５８】
参考として、沈殿物Ｂは、前記ＨＮＯ₃に溶解せず（分解しない意味）、更にＨＣｌにも溶解せずに残った物質である。この沈殿物Ｂに対して、アルカリ性溶液（例えばＮａＯＨ）中での溶解、更には酸溶液中での溶解を実施し、両溶液に対して非溶解（分解しない意味）の物質を回収し、ＩＣＰ−ＡＥＳなどによる定量分析によって、酸およびアルカリ性溶液に非溶解の物質（ｄ）を知る。（ｄ）は、主として原料Ｃｒに起因するＡｌ₂Ｏ₃などである。
【００５９】
例えば、処理雰囲気の選択とその質、処理温度、時間、冷却条件、原料粉（Ｃｕ、Ｃｒ）の調節などによって、接点素材中の酸非溶解性Ｃｕ化合物（ｙ）の量を、１０ｐｐｍ未満、１０ｐｐｍ〜６０００ｐｐｍの範囲にある素材を製造し試験に供した（比較例１〜２、実施例１〜４）。
【００６０】
すなわち、評価用代表接点としてＣｕ粉、Ｃｒ粉の成型体に対して、１０６０℃の加熱処理を与えたＣｕ−２５％Ｃｒ合金を選定し、これらの接点合金に対して、前記した定量化方法で接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量を、１０ｐｐｍ未満（比較例１）、１０ｐｐｍ（実施例１）、３０〜５０ｐｐｍ（実施例２）、１００〜３００ｐｐｍ（実施例３）、９００〜１０００ｐｐｍ（実施例４）、５６００〜６０００ｐｐｍ（比較例２）としたものを製造した。
【００６１】
再点弧特性の評価は、各接点について２４ｋｖ×５００Ａの回路を２０００回遮断した時の実施例２の再点弧発生数を１．０とした場合、０．１倍未満を評価（Ａ）、０．１〜０．８倍を評価（Ｂ）、０．８〜１．２を評価（Ｃ）、１．２〜１．５倍を評価（Ｄ）として分けこれらを「合格」と判断し、１．５〜１０倍を評価（Ｘ）、１０〜１００倍を評価（Ｙ）、１００倍以上を評価（Ｚ）として分けこれらを「不良」と判断した。
【００６２】
遮断特性の評価は、各接点について遮断電流値を測定し、後述する実施例２の遮断電流値を１．０とした時の倍率で示した。
【００６３】
［再点弧特性（再点弧発生の頻度）の評価結果］
接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量が、１０ｐｐｍ（実施例１）では、後述する実施例２の発生頻度と比較して０．１倍未満、０．１〜０．８倍を示し極めて良好な再点弧特性（評価（Ａ）〜（Ｂ））を発揮した。
【００６４】
酸非溶解性Ｃｕ化合物（ｙ）の量が、３０〜５０ｐｐｍ（実施例２）では、０．８〜１．２倍を示し極めて良好な再点弧特性（評価（Ｃ））を発揮した。
【００６５】
酸非溶解性Ｃｕ化合物（ｙ）の量が、１００〜３００ｐｐｍ（実施例３）では、実施例２の発生頻度と比較して０．８〜１．２倍を示し、良好な再点弧特性（評価（Ｃ））を発揮した。
【００６６】
酸非溶解性Ｃｕ化合物（ｙ）の量が、９００〜１０００ｐｐｍ（実施例４）では、実施例２の発生頻度と比較して１．２〜１．５倍以内を示し、良好な再点弧特性（評価（Ｃ）〜（Ｄ））を発揮した。
【００６７】
これに対して、酸非溶解性Ｃｕ化合物（ｙ）の量が、前記実施例１〜４より多い５６００〜６０００ｐｐｍ（比較例２）では、標準とする実施例２の発生頻度と比較して、１０〜１００倍および１００倍以上の再点弧発生頻度（評価（Ｙ）〜（Ｚ））を示し好ましくない。
【００６８】
以上の様に、酸非溶解性Ｃｕ化合物（ｙ）の量が、１０００ｐｐｍ以下の場合では、好ましい再点弧特性が見られるのに対して、酸非溶解性Ｃｕ化合物（ｙ）の量が、実施例４より多い５６００ｐｐｍ（比較例２）では、遮断直後の絶縁回復が著しく遅く耐電圧性低下で再点弧が多発し、１０〜１００倍以上の再点弧発生頻度（評価（Ｙ）〜（Ｚ））を示し、再点弧特性は著しく低下した。
【００６９】
明らかに接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量が所定量以下の時に良好な再点弧特性を発揮する。
【００７０】
なお、１０ｐｐｍ未満（比較例１）では、再点弧特性は実施例１と同等の評価（Ａ）を発揮しているが、しかし接点素材中の酸非溶解性Ｃｕ化合物（ｙ）の量を安定して１０ｐｐｍ未満とするにはコスト高となり、製造工程が繁雑となるのみで、経済的価値が低い。
【００７１】
［遮断特性の評価結果］
接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量が、３０〜５０ｐｐｍ（実施例２）の時の遮断倍率を、１．０倍とした時、酸非溶解性Ｃｕ化合物（ｙ）の量が１０ｐｐｍ（実施例１）の時の遮断倍率は、（１．０〜１．１）倍、酸非溶解性Ｃｕ化合物（ｙ）の量が１００〜３００ｐｐｍ（実施例３）の時の遮断倍率も、（０．９５〜１．０）倍を示し、酸非溶解性Ｃｕ化合物（ｙ）の量が、９００〜１０００ｐｐｍ（実施例４）の時の遮断倍率も、（０．９〜０．９５）倍を示し、いずれも標準とする実施例２とほぼ同程度若しくはそれ以上の好ましい遮断特性にある。
【００７２】
これに対して、酸非溶解性Ｃｕ化合物（ｙ）の量が、前記実施例１〜４よりも多い５６００〜６０００ｐｐｍ（比較例２）の時の遮断倍率は、（０．８〜０．９５）倍に低下した。明らかに接点素材中の酸非溶解性Ｃｕ化合物（ｙ）の量が増加する場合に遮断特性は低下する傾向にある。
【００７３】
なお、１０ｐｐｍ未満（比較例１）では、遮断特性は実施例１と同等の（１．０〜１．１）倍を発揮しているが、しかし接点素材中の酸非溶解性Ｃｕ化合物（ｙ）の量を安定して１０ｐｐｍ未満とするにはコスト高となり、製造工程が繁雑となるのみで、経済的価値が低い。
【００７４】
従って、接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量は、１０００ｐｐｍ以下とすることが好ましく、下限量は前記再点弧の時と同様に経済性によって決定される。
【００７５】
（実施例５〜７、比較例３〜４）
前記実施例１〜４、比較例１〜２では、接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量の再点弧特性、遮断特性に及ぼす影響を、接点合金中のＣｕ量を７５重量％（以下接点材料については重量％）としたＣｕ−２５％Ｃｒ接点について示したが、本発明技術はこれに限ることなく上記Ｃｕ−２５％Ｃｒ接点以外でもその効果を発揮する。すなわち接点合金中のＣｕ量を５％とした５％Ｃｕ−Ｃｒ（比較例３）、１０％Ｃｕ−Ｃｒ（実施例５）、５０％Ｃｕ−Ｃｒ（実施例６）、８５％Ｃｕ−Ｃｒ（実施例７）、９８％Ｃｕ−Ｃｒ（比較例４）を製造した上で、これらの接点材料の中から酸非溶解性Ｃｕ化合物（ｙ）の量が、１００〜３００ｐｐｍの範囲内にある接点材料を選択した上で、前記評価を実施した。
【００７６】
［再点弧特性］
１０％Ｃｕ−Ｃｒ（実施例５）、５０％Ｃｕ−Ｃｒ（実施例６）、８５％Ｃｕ−Ｃｒ（実施例７）の時には、標準とする実施例２と同等の０．１〜０．８倍および０．８〜１．２倍（評価（Ｂ）〜（Ｃ））を示し良好な再点弧特性を発揮している。
【００７７】
これに対して、接点中のＣｕ量が実施例７の８５％より多い９８％Ｃｕ−Ｃｒ（比較例４）では、電流遮断時に一部に溶着現象の発生や接点表面の荒れが大きくなる現象を呈し、接点の耐電圧特性の低下によって、１．５〜１０および１００以上（評価（Ｘ）〜（Ｚ））を示し、再点弧特性は大きなバラツキを示すと共に、著しく低下し好ましくない。
【００７８】
なお、接点中のＣｕ量を５％とした５％Ｃｕ−Ｃｒ（比較例３）の場合では、標準試料（実施例２）と比較して同等以上の再点弧特性を示し、再点弧発生の頻度は０．１〜８倍および０．８〜１．２倍（評価（Ｂ）〜（Ｃ））を示し良好な再点弧特性を発揮している。
【００７９】
以上により、本発明技術を適応する接点素材中に含有されるＣｕ量は８５％以下が好ましい。
【００８０】
［遮断特性］
遮断特性は、接点中のＣｕ量が１０％Ｃｕ−Ｃｒ（実施例５）の遮断倍率は（０．９〜０．９５）倍、５０％Ｃｕ−Ｃｒ（実施例６）の遮断倍率は（１．０）倍、８５％Ｃｕ−Ｃｒ（実施例７）の遮断倍率は（１．０〜１．１）倍を示し、標準とする実施例２とほぼ同程度の遮断特性にある。
【００８１】
接点中のＣｕ量が実施例５の１０％より少ない５％Ｃｕ−Ｃｒ（比較例３）の遮断倍率は、接点材料自体の低導電率化（８％ＩＡＣＳ以下）によって（０．５５〜０．７）倍を示し、大幅な低下と大幅なバラツキを示している。
【００８２】
これに対して、接点中のＣｕ量が実施例７の８５％より多い９８％Ｃｕ−Ｃｒ（比較例４）の遮断倍率は(０．７〜１．１５)倍を示し、接点表面の荒れが起因して遮断特性は大きなバラツキをした。
【００８３】
以上により、本発明技術を適応する接点素材中に含有されるＣｕ量は、１０〜８５重量％の範囲の接点を使用するのが好ましい。
【００８４】
すなわち、接点合金のＣｕ量が１０重量％未満では、接点材料自体の低導電率化によって遮断特性が大幅に低下する。また、接触抵抗、回路抵抗、温度上昇の増加を招き遮断電流値の低下、定格開閉電流値の低下を来たし好ましくない。Ｃｕ量が８５重量％を越えると、電流の遮断時に耐アーク性が劣り遮断後の接点表面は著しい荒れを示し、この荒れが再点弧発生の原因の１つとなる。
【００８５】
また、接点材料の導電率という観点からは、少なくとも１０％ＩＡＣＳの導電率を持つ合金であることが好ましい（実施例５〜７）。導電率が１０％ＩＡＣＳ未満の場合、すなわち導電率が８％ＩＡＣＳ以下の比較例３では再点弧特性には変化は見られていないが、遮断特性の低下が認められる。
【００８６】
（実施例８〜９）
前記実施例１〜７では、接点素材中の導電性成分としてＣｕを選択した場合の例について示したが、本発明技術はこれに限ることなくＣｕ以外でもその効果を発揮する。
【００８７】
すなわち接点素材中の導電性成分をＡｇとした４０％Ａｇ−Ｃｒ（実施例８）であっても、再点弧発生の頻度は１．２〜１．５倍の良好な再点弧特性（評価（Ｄ））を示し合格の範囲である。
【００８８】
さらに、導電性成分をＡｇ＝５４％、Ｃｕ＝２１％とした７５％（Ａｇ＋Ｃｕ）−Ｃｒ（実施例９）であっても、再点弧発生の頻度は０．８〜１．２倍および１．２〜１．５倍の良好な再点弧特性（評価（Ｃ）〜（Ｄ））を示し合格の範囲である。
【００８９】
遮断特性は、標準とする実施例２の遮断特性を１．０とした場合の、（０．９）倍（実施例８）、（０．９５〜１．０５）倍（実施例９）を示しいずれも合格の範囲である。
【００９０】
以上のように、導電性成分すなわちＣｕマトリックスの一部または総てをＡｇで置換しても、Ｃｕマトリックスの場合と同等の特性を発揮する。
【００９１】
（実施例１０〜１２、比較例５〜６）
前記実施例１〜９、比較例１〜４では、再点弧特性、遮断特性に及ぼす接点合金中の酸非溶解性Ｃｕ化合物（ｙ）の量の影響を、接点合金中のＣｕマトリックス中に固溶させたＣｒ（ｂ）の量を０．０２％（重量％）とした接点について示したが、本発明技術でのＣｒ（ｂ）の量は、０．０２％に限ることなくその効果を発揮する。
【００９２】
すなわち接点合金中のＣｕマトリックス中に固溶させたＣｒ（ｂ）の量を、０．００５％、０．１％、０．５％とした７５％Ｃｕ−Ｃｒ（実施例１０〜１２）、および０．００５％未満とした７５％Ｃｕ−Ｃｒ（比較例５）、０．５％より多い量とした７５％Ｃｕ-Ｃｒ（比較例６）の各合金を、主として接点製造時の冷却過程での冷却速度を調整しながら製造した上で、これらの中から接点材料中の酸非溶解性Ｃｕ化合物（ｙ）の量が、１００〜３００ｐｐｍの範囲内にある接点材料を選出して前記評価を実施した。
【００９３】
［再点弧特性］
導電成分中に固溶する耐弧成分の量すなわちＣｕマトリックス中に固溶させたＣｒ（ｂ）の量が、実施例２の０．０２％よりも少ない０．００５％の場合（実施例１０）では、実施例２より優れた０．１倍未満および０．１〜０．８倍の再点弧特性（評価（Ａ）〜（Ｂ））を示した。Ｃｕマトリックス中に固溶させたＣｒ（ｂ）の量が、０．１％の場合（実施例１１）、０．５％の場合（実施例１２）では、いずれも０．８〜１．２倍（評価（Ｃ））を示し、好ましい再点弧特性を示した。
【００９４】
これに対して、Ｃｕマトリックス中に固溶するＣｒ（ｂ）の量が、０．５％より多い場合（比較例６）では、０．８〜１．２倍から１０〜１００倍（評価（Ｃ）〜（Ｙ））を示し、バラツキ幅の大きい再点弧特性を示し好ましくない。
【００９５】
一方、Ｃｕマトリックス中に固溶するＣｒ（ｂ）の量を実施例１０の０．００５％より少なくした比較例５では、前記した実施例１０と同等の０．１倍未満および０．１〜０．８倍（評価（Ａ）〜（Ｂ））を示し良好であった。しかしこの場合製造コストが高く供給性に難があり製造技術的観点から、本発明の好ましい範囲から除外する。
【００９６】
［遮断特性］
Ｃｕマトリックス中に固溶するＣｒ（ｂ）の量が、０．０２％（実施例２）より少ない０．００５％（実施例１０）の遮断倍率は、(１．０〜１．１)倍、（ｂ）の量が０．１％（実施例１１）の遮断倍率は（０．９〜１．０）倍、（ｂ）の量が０．５％（実施例１２）の遮断倍率は（０．９〜０．９５）倍を示し、いずれも良好の範囲である。
【００９７】
これに対して、Ｃｕマトリックス中に固溶するＣｒ（ｂ）の量を、実施例１２の０．５％より多くした比較例６では、（０．６〜０．７５）倍に遮断特性が低下し好ましくない。
【００９８】
以上から、本発明を実施する上では、接点合金中のＣｕマトリックス中に固溶させたＣｒ（ｂ）の量は、０．００５〜０．５重量％の範囲にある接点合金を選択することが好ましい。
【００９９】
すなわち、Ｃｕマトリックス中に固溶させるＣｒ（ｂ）の量が０．５重量％を越すと、接点の製造技術上、経済性の面で問題であると共に、接点合金自体の導電率が低下し遮断特性が大幅に低下する。また、Ｃｕマトリックス中に固溶させるＣｒ（ｂ）の量を０．００５重量％未満に制御するのも、工業的にも経済的にも得策でない。
【０１００】
（実施例１３〜１４、比較例７）
前記実施例１〜１２、比較例１〜６では、接点中の耐弧成分の種類としてＣｒを選択したＣｕＣｒ接点について再点弧特性、遮断特性に及ぼす効果を示したが、本発明技術はこれに限ることなくＣｕ-Ｃｒ接点以外でもその効果を発揮する。
【０１０１】
［再点弧特性］
すなわち、接点合金中のＣｕマトリックス中に固溶させたＣｒ（ｂ）の量を、０．０２％、接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量を、１００〜３００ｐｐｍ、残部をＣｕとした上で、接点素材中に存在する耐弧性成分（重量比）の種類を、ＣｒＷ（Ｃｒ：Ｗ＝９：１）、ＣｒＷ（Ｃｒ：Ｗ＝５：５）で置換しても、標準としている実施例２と同等またはそれ以上の好ましい再点弧特性（評価（Ａ）〜（Ｂ）ないし評価（Ｂ）〜（Ｃ））を示した（実施例１３〜１４）。
【０１０２】
しかし、ＣｒとＷとの比率がＣｒ：Ｗ＝２：８の場合の様に、Ｃｒ成分が少ない時には、再点弧発生頻度が０．８〜１．２倍および１．５〜１０倍の間のバラツキの大きい再点弧特性（評価（Ｃ）〜（Ｘ））を示した（比較例７）。
【０１０３】
［遮断特性］
ＣｒＷ（Ｃｒ：Ｗ＝９：1）の実施例１３では、（０．９〜１．１）倍、ＣｒＷ（Ｃｒ：Ｗ＝５：５）の実施例１４でも、（０．９〜１．１）倍の良好な遮断特性を示した。
【０１０４】
しかし、Ｃｒ：Ｗ＝２：８の場合の様に、耐弧性成分中のＣｒ成分が少ない時には、多量の熱電子放出の影響で遮断特性は、（０．４〜０．５５）倍に大幅に低下した。この場合、遮断直後の絶縁回復が著しく遅れ、耐電圧性低下で再点弧特性にバラツキ発生、遮断特性も大幅に低下した（比較例７）。
【０１０５】
（実施例１５〜１８）
［再点弧特性］
接点合金中のＣｕマトリックス中に固溶させたＣｒ（ｂ）の量を、０．０２％、接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量を、１００〜３００ｐｐｍ、残部をＣｕとした上で、接点素材中に存在する耐弧性成分（重量比）の種類を、ＣｒＭｏ（Ｃｒ：Ｍｏ＝９：１）、ＣｒＴａ（Ｃｒ：Ｔａ＝９：１）、ＣｒＮｂ（Ｃｒ：Ｎｂ＝９：１）で置換しても、標準としている実施例２と同等以上の再点弧特性（評価（Ａ）〜（Ｂ））を示した（実施例１５、１７〜１８）。
【０１０６】
［遮断特性］
接点素材中に存在する耐弧性成分（重量比）の種類をＣｒＭｏ（Ｃｒ：Ｍｏ＝９：１）、ＣｒＴａ（Ｃｒ：Ｔａ＝９：１）、ＣｒＮｂ（Ｃｒ：Ｎｂ＝９：１）で置換しても、標準としている実施例２と同等以上の好ましい遮断特性である（０．９５〜１．１５）倍を示し、良好な特性である（実施例１５、１７〜１８）。
【０１０７】
＜実施例１６＞
なお、上記実施例１〜１４では、接点合金中の導電成分（Ｃｕマトリックス）中に固溶させた耐弧成分の種類としてＣｒを選択したが、実施例１６での導電成分（Ｃｕマトリックス）中に固溶させた耐弧成分の種類はＣｒＴｉとなる。この場合であってもその効果を発揮する。すなわち接点合金中の導電成分中に固溶する耐弧成分を（ＣｒＴｉ）とし、その量を、０．０２とした７５％Ｃｕ−Ｃｒ（実施例１６）を製造し、前記評価を実施した。
【０１０８】
［再点弧特性］
再点弧発生の頻度は実施例２と同等以上の０．１倍未満および０．１〜０．８倍（評価（Ａ）〜（Ｂ））を示し、良好な再点弧特性を発揮している。
【０１０９】
［遮断特性］
遮断特性も、遮断倍率（０．９５〜１．１５）倍を示し実施例２と同等の範囲である。
【０１１０】
以上から、前記接点に於ける耐弧性成分は、Ｃｒの一部を５０重量％以下のＷ、Ｍｏ、Ｔａ、Ｎｂ、Ｔｉの１つで置換しても同等の効果を得る（実施例１３〜１８）。
【０１１１】
すなわち、Ｃｒの一部をＷ、Ｍｏ、Ｔａ、Ｎｂ、Ｔｉの１つで置換することによって、Ｃｕ−Ｃｒ接点素材全体の機械的強度を大とし、Ｃｒ粒の脱落が引き金となって引き起こされる再点弧発生を軽減化することができる。
【０１１２】
（実施例１９〜２０、比較例８〜９）
前記実施例１〜１８、比較例１〜７では、Ｃｕマトリックス中の耐弧成分（Ｃｒ、ＣｒＷなど）の粒子直径を４０〜８０μｍとした場合について、再点弧特性、遮断特性に及ぼす効果を示したが、本発明技術で使用する耐弧成分の粒子直径は、これに限ることなくその効果を発揮する。
【０１１３】
すなわち、接点合金中のＣｕマトリックス中に固溶させたＣｒ（ｂ）の量を、０．０２％、接点素材中に含有される酸非溶解性Ｃｕ化合物（ｙ）の量を、１００〜３００ｐｐｍ、残部をＣｕとした上で、前記と同等の評価を実施した。
【０１１４】
［再点弧特性］
耐弧成分（Ｃｒ）の粒子直径を０．１〜２５μｍ、７０〜１５０μｍとしても、標準としている実施例２と比較してほぼ同等の好ましい再点弧特性（評価（Ｂ）〜（Ｃ）および評価（Ｃ）〜（Ｄ））を示した（実施例１９〜２０）。
【０１１５】
しかし、Ｃｕマトリックス中の耐弧成分（Ｃｒ）の粒子直径を、０．１μｍ未満とした場合には、標準としている実施例２以上の好ましい再点弧特性（評価（Ａ）〜（Ｂ））を示しているにもかかわらず、耐弧成分(Ｃｒ)の粒子直径を０．１μｍ未満とする為の生産性の低さなど高い製造コストによって本発明外とする（比較例８）。
【０１１６】
平均粒子直径が１５０μｍを越える接点では、標準としている実施例２と比較した再点弧発生の頻度は、１．５〜１０倍および１００倍以上（評価（Ｘ）〜（Ｚ））を示し、大幅な低下と大きなバラツキ幅を示す（比較例９）。
【０１１７】
［遮断特性］
耐弧成分（Ｃｒ）の粒子直径を０．１〜２５μｍ、７０〜１５０μｍとしても、（０．９５〜１．０５）倍および（１．０〜１．１）倍を示し、標準としている実施例２の遮断特性１．０と比較してほぼ同等の好ましい値である（実施例１９〜２０）。
【０１１８】
しかし、平均粒子直径が１５０μｍを越える接点での遮断倍率は、（０．７５〜１．０）倍を示し、やはり大きなバラツキ幅を示し好ましくない（比較例９）。
【０１１９】
以上から、前記接点中の耐弧性成分は、０．１〜１５０μｍの平均粒子直径を持つことが好ましい。
【０１２０】
（実施例２１〜２６、比較例１０）
前記実施例１〜２０、比較例１〜９では、接点合金中にＢｉなど耐溶着性を改善させる為の補助成分を含有していないＣｕＣｒ接点について、再点弧特性、遮断特性に及ぼす影響を示したが、本発明技術はこれに限ることなく上記した接点合金中にＢｉなどの補助成分が所定量以内存在してもその効果を維持する。
【０１２１】
すなわち、接点合金中にＢｉを０．１％、１．０％添加した７５％Ｃｕ−Ｃｒ合金（実施例２１〜２２）、同じくＢｉを２．０％添加した７５％Ｃｕ−Ｃｒ合金（比較例１０）、Ｐｂを０．３％添加した７５％Ｃｕ−Ｃｒ合金（実施例２３）、Ｓｂを０．１％添加した７５％Ｃｕ−Ｃｒ合金（実施例２４）、Ｔｅを３．０％添加した７５％Ｃｕ−Ｃｒ合金（実施例２５）、Ｓｅを１．０％添加した７５％Ｃｕ−Ｃｒ合金（実施例２６）を製造した上で、前記同様の評価を実施した。
【０１２２】
［再点弧特性］
再点弧発生の頻度は、Ｂｉ量を０．１％とした実施例２１では０．１〜０．８倍および０．８〜１．２倍（評価（Ｂ）〜（Ｃ））、Ｂｉ量を１．０％とした実施例２２では０．８〜１．２倍および１．２〜１．５倍（評価（Ｃ）〜（Ｄ））を示し、実施例２とほぼ同等かそれ以上の好ましい再点弧特性を示した。
【０１２３】
しかしＢｉ量を２．０％とした比較例１０では、１０〜１００倍（評価（Ｙ））および１００倍以上（評価（Ｚ））を示し、再点弧特性の大幅な低下とバラツキ幅の拡大が見られ好ましくない。なおＢｉの存在によって実施例２よりも大幅に耐溶着性が改善される。
【０１２４】
［遮断特性］
遮断特性は、Ｂｉ量を０．１％とした実施例２１では、（０．９５）倍、Ｂｉ量を１．０％とした実施例２２では（０．９）倍を示し、いずれも実施例２とほぼ同等の特性を示した。
【０１２５】
これに対して、Ｂｉ量を２．０％とした比較例１０では、遮断時に生ずるＢｉの選択的蒸発による接点表面の荒損によって耐電圧性の低下を招く結果、再点弧特性は評価（Ｙ）〜（Ｚ）に劣化すると共に、遮断倍率も（０．３〜０．４５）倍に大幅に低下し好ましくない。
【０１２６】
Ｐｂ量を０．３％とした実施例２３、Ｓｂ量を０．１％とした実施例２４、Ｔｅ量を３．０％とした実施例２５、Ｓｅ量を１．０％とした実施例２６などの他の耐溶着性成分を含有する７５％Ｃｕ−Ｃｒ合金に於いても、再点弧特性は、０．８〜１．２倍（評価（Ｃ））および１．２〜１．５倍（評価（Ｄ））を示し、良好な再点弧特性を示すと共に、遮断倍率も（０．９）倍（実施例２３〜２４）、および（０・９〜０．９５）倍（実施例２５〜２６）を示し良好な遮断特性を示す。
【０１２７】
以上のように、ＣｕＣｒ接点中の１重量％以下のＢｉ、Ｐｂ、Ｓｂの存在は電流遮断後の接点表面荒れを安定化させ、再点弧発生レベルを一層低くするのに貢献する。しかし、１％を越すＢｉ、Ｐｂ、Ｓｂの存在は、再点弧発生の頻度を増加させて好ましく無い。５％重量以下のＴｅ、Ｓｅの存在も、電流遮断後の接点表面荒れを安定化させ、再点弧発生レベルを低くする。
【０１２８】
（実施例２７〜２９、比較例１１〜１２）
本発明の実施に於ける真空遮断器の通電軸の導電率は、通常１００％ＩＡＣＳのＣｕを用いるが、本発明では９５％ＩＡＣＳの場合（実施例２７）、７０％ＩＡＣＳの場合（実施例２８）であっても、再点弧発生頻度は評価（Ｂ）〜（Ｃ）であり再点弧特性には変化は見られていないが、通電軸の導電率が５０％ＩＡＣＳの０．３重量％Ｚｒ−Ｃｕ合金を用いた場合（比較例１１）では、遮断特性に於いて（０．５〜０．６５）倍の遮断倍率を示し、遮断特性は大幅に低下する。
【０１２９】
従って、通電軸の導電率は少なくとも７０％ＩＡＣＳの導電率を持つことが好ましい。
【０１３０】
すなわち、通電軸の導電率が７０％ＩＡＣＳ未満では、回路抵抗を増加させ温度上昇の増加を招き遮断電流値の低下、定格開閉電流値の低下を来たし好ましくない。
【０１３１】
また、純Ｃｕは、機械的な外力に対する変形抵抗性が劣るが設計的な配慮を行うことによって、１００％ＩＡＣＳの導電率を容易に得られるので、好適な通電軸材料として使用することができる。
【０１３２】
また、本発明の実施に於ける真空遮断器のコイル電極は、通常１００％ＩＡＣＳのＣｕを用いるが、本発明では、コイル電極が０．１重量％Ｃｒ−Ｃｕで製造した７０％ＩＡＣＳの場合（実施例２９）であっても、再点弧発生頻度は評価（Ｂ）〜（Ｃ）であり再点弧特性には変化は見られていない。コイル電極の導電率が５０％ＩＡＣＳの０．３重量％Ｚｒ−Ｃｕ合金を用いた場合（比較例１２）では、遮断特性に於いて（０．４〜０．５５）倍の遮断倍率を示し、遮断特性の大幅な低下が認められる。
【０１３３】
従って、コイル電極の導電率は少なくとも７０％ＩＡＣＳの導電率を持つことが好ましい。
【０１３４】
すなわち、コイル電極の導電率が７０％ＩＡＣＳ未満では、やはり回路抵抗を増加させ温度上昇の増加を招き遮断電流値の低下、定格開閉電流値の低下を来たし好ましくない。
【０１３５】
また純Ｃｕは、機械的な外力に対する変形抵抗性が劣るが設計的な配慮を行うことによって、１００％ＩＡＣＳの導電率を容易に得られるので、好適なコイル電極材料として使用することができる。
【０１３６】
【発明の効果】
以上説明したように、本発明の真空遮断器によれば、再点弧特性と遮断特性とを両立させることができる。
【図面の簡単な説明】
【図１】本発明に係る真空遮断器の実施例１〜９および比較例１〜４の評価条件を示す表図。
【図２】本発明に係る真空遮断器の実施例１０〜２０および比較例５〜９の評価条件を示す表図。
【図３】本発明に係る真空遮断器の実施例２１〜２９および比較例１０〜１２の評価条件を示す表図。
【図４】本発明に係る真空遮断器の実施例１〜９および比較例１〜４の評価結果を示す表図。
【図５】本発明に係る真空遮断器の実施例１０〜２０および比較例５〜９の評価結果を示す表図。
【図６】本発明に係る真空遮断器の実施例２１〜２９および比較例１０〜１２の評価結果を示す表図。
【図７】代表的な真空遮断器の構成例を示す断面図。
【図８】代表的な真空遮断器の他の構成例を示す断面図。
【符号の説明】
１０１…絶縁容器
１０２ａ、１０２ｂ…蓋体
１０３…真空容器
１０４、１０５…接点
１０６、１０７…通電軸
１０８…ベローズ
１０９…アークシールド
Ｍ…通電軸１０７の移動方向
４０、５０…平板型電極またはコイル電極
４１、５１…接点[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum circuit breaker comprising a vacuum valve provided with a contact that achieves both excellent breaking characteristics and re-ignition characteristics.
[0002]
[Prior art]
In general, in a vacuum circuit breaker composed of vacuum valves, the contact of the vacuum valve that cuts off the current in a high vacuum using the diffusibility of the arc in vacuum is composed of two fixed and movable contacts facing each other. ing.
[0003]
As shown in FIG. 7, a pair of contacts 104 and 105 are provided opposite to each other in a vacuum vessel 103 in which openings at both ends of the insulating vessel 101 are closed by lids 102a and 102b, and these are attached to the lids 102a and 102b. Are attached to the ends of the current-carrying shafts 106 and 107 inserted through the vacuum vessel 103, and one of the current-carrying shafts 107 can be moved in the axial direction by an operating mechanism (not shown). The movable contact 105, which is the other contact, can be brought into contact with or separated from the fixed contact 104. In this case, a bellows 108 is provided between the lid 102b and the energizing shaft 107 so as to hold the inside of the vacuum vessel 103 in a vacuum-tight manner and allow the energizing shaft 107 to move in the axial direction. In the figure, reference numeral 109 denotes a shield provided so as to surround the contact points 104 and 105 and the energizing shafts 106 and 107.
[0004]
The vacuum circuit breaker is normally energized when both the contacts 104 and 105 are in contact with each other. When the energizing shaft 107 is moved in the direction of arrow M in the figure by the operation from this state, the movable contact 105 is separated from the fixed contact 104, and an arc is generated between the two contacts. This arc is maintained by the generation of metal vapor from the cathode, for example, the movable contact 105 side. When the current reaches the zero point (zero point), the generation of metal vapor stops and the arc cannot be maintained, and the interruption is completed.
[0005]
By the way, the arc generated between the two contacts 104 and 105 becomes extremely unstable due to the interaction between the magnetic field generated by the arc itself and the magnetic field generated by the external circuit when the breaking current is large. As a result, the arc moves on the contact surface (when the contact is attached to and integrated with the electrode, the arc may also move on the electrode surface) and is shifted to the end or the periphery of the contact. The portion is locally heated to release a large amount of metal vapor, and the degree of vacuum in the vacuum vessel 103 is lowered. As a result, the breaking performance of the vacuum circuit breaker decreases. These often depend on the state of the contact represented by the metallographic structure.
[0006]
FIG. 8 shows a vacuum valve in which a pair of contacts 41 and 51 are provided facing each other, and a flat plate electrode 40 is mounted on the back of the contact 41 and a flat electrode 50 is mounted on the back of the contact 51. Further, the coil electrode 40 can be mounted on the back surface of the contact 41, and the coil electrode 50 can be mounted on the back surface of the contact 51, respectively.
[0007]
In general, in a vacuum circuit breaker, in addition to the three basic requirements of large current interruption performance, withstand voltage performance and welding resistance, suppression of the occurrence of a re-ignition phenomenon is an important requirement.
[0008]
However, because some of these requirements are contradictory, it is impossible to satisfy all the requirements with a single metal species. For this reason, in many contact materials that are in practical use, a combination of two or more elements that complement each other in deficient performance can be used for specific purposes such as for high currents and high withstand voltages. Selection of contact materials suitable for the application has been made, and vacuum valves with excellent characteristics have been developed. However, there are still many products that can be used at the expense of some functions. In fact, a vacuum valve that sufficiently satisfies the increasing demand has not yet been obtained.
[0009]
For example, a Cu—Cr alloy (Japanese Patent Publication No. 45-35101) containing about 50 wt% (wt%) of Cr is known as a contact for the purpose of interrupting a large current. This alloy realizes high voltage and large current interruption due to the effect that Cr itself maintains vapor pressure characteristics substantially equivalent to Cu and exhibits a powerful gas getter action. It is widely used as a contact that can achieve both.
[0010]
Since this alloy uses highly active Cr, contact materials can be manufactured (sintering process, etc.) while paying sufficient attention to the selection of raw material powder, mixing of impurities, atmosphere control, etc. Although it is made into a contact product while giving consideration to processing from the material to the contact piece, the occurrence of re-ignition is a trigger, and there is a case where the interruption performance is lowered, and the improvement is desired.
[0011]
[Problems to be solved by the invention]
CuCr contacts are mainly due to their close vapor pressure characteristics at high temperatures, and the contact surface shows relatively smooth damage characteristics even after interruption, and exhibits stable electrical characteristics. Yes.
[0012]
In recent years, as a result of routine adaptation to circuits where higher current interruption and higher voltage may be applied, the surface condition of a new product processed as a contact, the damage state of the contact surface after current interruption In some cases, when the next steady-state current is opened and closed, it causes an abnormal increase in contact resistance and an abnormal increase in temperature, or it shows a withstand voltage failure and contributes to the occurrence of re-ignition.
[0013]
However, even if the surface state of the contact is controlled, the occurrence of re-ignition cannot be suppressed completely, and the actual current interruption characteristic is not obtained.
[0014]
Furthermore, for example, in order to stabilize the re-ignition characteristic and the interruption characteristic of the CuCr alloy, the composition of the contact material, the component amount (Cr amount), the structure morphology (particle size, particle size distribution, degree of segregation, vacancy existing in the alloy) To the extent of gas) and the surface morphology of the contacts. However, in spite of these optimizations, in the recent adaptation situation described above, there are still variations in the re-ignition characteristics, especially the further stabilization of the re-ignition characteristics and the interruption characteristics. A vacuum circuit breaker that combines both characteristics has become necessary.
[0015]
An object of the present invention is to provide a vacuum circuit breaker having both re-igniting characteristics and breaking characteristics.
[0016]
[Means for Solving the Problems]
The vacuum circuit breaker according to the present invention is a vacuum circuit breaker comprising a vacuum vessel, a bellows, a current-carrying shaft, and a pair of contact points facing each other. An electrically conductive component composed of 10 to 85% by weight of Cu and an arc resistant component composed of 90 to 15% by weight of Cr with the balance having an average particle diameter of 0.1 to 150 μm; Cu-Cr-based contact alloy containing a Cu matrix in the alloy Acid insoluble Cu compound which is a Cu compound insoluble in acidic solution The amount of is 10 ppm to 1000 ppm.
[0017]
With such a configuration, it is possible to achieve both re-ignition characteristics and interruption characteristics.
[0018]
That is, acid insoluble Cu in CuCr contacts Compound If the amount exceeds 1000 ppm, the frequency of re-ignition increases and the acid-insoluble Cu for each material. Compound As a result, the re-ignition is unstable, and the re-ignition becomes unstable.
[0019]
Acid insoluble Cu in CuCr contacts Compound Although it is technically possible to make the amount of less than 10 ppm, it is not a good idea from the viewpoint of economy.
[0020]
If the amount of Cu exceeds 85% by weight, the arc resistance is inferior when the current is interrupted, and the contact surface after the interruption is markedly rough. This roughness is one of the causes of re-ignition. If the amount of Cu is less than 10% by weight, a sufficient barrier property cannot be obtained due to low conductivity, and contact resistance property and temperature rise property are also deteriorated.
[0021]
The average particle diameter of the arc resistant component exhibits stable re-ignition characteristics when Cr particles in the range of 0.1 to 150 μm occupy at least 75% by volume of all Cr particles.
[0022]
Setting the average particle diameter of the Cr particles to less than 0.1 μm results in a significant increase in cost from the viewpoint of production technology, and there is a difficulty in supplyability. When the thickness exceeds 150 μm, it is difficult to obtain a smooth and uniform state by leaving scratched scratches at the interface between the Cr particles and the Cu phase on the finished contact surface, and the re-ignition characteristics are greatly deteriorated.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0024]
According to research, the contact surface immediately after the current is interrupted becomes extremely high mainly due to arc heat, and a large amount of gaseous components and solid components are released from the molten contact surface into the electrode space. Among these, when the gaseous component stays between the electrodes for a predetermined time or more, the excellent insulating property of the vacuum is destroyed. Therefore, in order to maintain the dielectric strength between the electrodes, the absolute amount of the gaseous component released from the contact surface must be minimized in advance, or the released gaseous component can be quickly diffused and removed between the electrodes. It is also important.
[0025]
That is, in the case of a substance that can be easily decomposed or removed by arc heat in the substance on the contact surface or inside the contact (the above-mentioned gaseous component or solid component), the stage before the interruption (arc It was observed that there was a low probability that it would move directly into the electrode space at a very early stage of the temperature rising process and directly cause reignition.
[0026]
On the other hand, in the case of substances that cannot be easily decomposed or removed, it was observed that decomposition or removal proceeds even after the completion of blocking and moves to the electrode space, which is an important cause of reignition.
[0027]
In the case of a gas (gas) generated in the process of decomposing the substance described above, the component having a larger mass number has a slower diffusion rate and tends to remain in the electrode space, and the recovery of the degree of vacuum tends to be delayed, resulting in insulation. Trigger destruction.
[0028]
Here, there are two types of substances existing on the surface of the contact or inside the contact, a substance that can be easily eliminated by arc heat or Joule heat and a substance that cannot be easily eliminated. Of these, the latter material is particularly important for reignition. That is, it is important to reduce substances that cannot be easily decomposed or released / removed into the electrode space at the stage before the current is cut off (or at the very initial stage where the temperature of the contacts is rising). Become. For that purpose, it is also important how to quantify the amount of substances that cannot be easily decomposed or removed without interrupting the actual current.
[0029]
If all the contacts are fully heated to the vapor state, the amount of surface gas and the amount of internal gas released at that time can be captured, but all the contacts are completely heated to the vapor state. In fact, there is a substance that does not decompose during melting, so it is impossible to capture the total amount of substance present on the surface or inside the contact.
[0030]
When a CuCr alloy is dissolved with acids such as hydrochloric acid and nitric acid, it is dissolved in an acid and removed, and separately from this, an acid-insoluble Cu that is an insoluble material that does not dissolve in an acid Compound (Y) remains.
[0031]
The former component which can be dissolved and removed in the acid easily diffuses to the contact surface when it receives the arc heat and corresponds to a component which is easily removed.
[0032]
In contrast, the latter components that are not dissolved in the acid and cannot be removed exist as Cu compounds such as Cu oxide and Cu nitride as solid bodies on the contact surface and inside the contact, and these are easily decomposed. Or it corresponds to the substance which is hard to be removed, and has an important meaning for reignition suppression.
[0033]
When the acid non-dissolved substance (y) present on the contact surface portion is subjected to an arc, it decomposes and instantaneously releases a large amount of gas or a decomposition product, which is re-ignited. Contributes to the occurrence. The acid non-dissolved substance (y) existing in one contact is also decomposed by the arc to release a large amount of gas or a decomposition product in the same manner. It becomes. Since the diffusion to the contact surface is delayed, it contributes to the re-ignition seen after a certain period of time after the interruption.
[0034]
(Experiment 1): According to experiments by the inventors, as one means for causing a very small amount of acid-insoluble Cu to be present in a contact, a submicron-class Cu oxide suspended in an organic solvent is coated. A deposited Cr skeleton was manufactured, and a CuCr alloy having a very small amount of fine oxidized Cu (copper) inside was manufactured by an infiltration method in which Cu was infiltrated into the voids of the Cr skeleton. It is easy to adjust the amount of fine oxidized Cu in the CuCr alloy by adjusting the amount of oxidized Cu suspended in the organic solvent.
[0035]
As another means, a CrCr alloy was manufactured by solid-phase sintering of Cr powder and Cu powder coated with submicron-grade Cu oxide suspended in an organic solvent.
[0036]
In any CuCr alloy obtained by any of the manufacturing methods, when the amount of Cu oxide is large, the frequency of re-ignition increases, whereas when the amount of Cu oxide is small, re-spotting occurs. The frequency of arcs tends to be very low. When this acid-insoluble substance (y) is analyzed, the presence of an acid-insoluble Cu compound (y) is particularly confirmed therein.
[0037]
(Experiment 2): According to other observations by the inventors, there are cases where extremely fine precipitates are present and no precipitate is present in the contact material.
[0038]
In an actual vacuum circuit breaker, when microscopic observations of the contacts mounted on a vacuum valve with a high re-ignition frequency, extremely fine precipitates and inclusions (both insoluble in acid) were confirmed. In this case, in the substance (y) insoluble in the acid, Cu Compound Was confirmed to exist in a certain amount or more.
[0039]
On the other hand, when the contact point mounted on the vacuum valve having a low re-ignition frequency is observed microscopically, Cu is contained in the fine precipitates and inclusions (both insoluble in acid). Compound Tended to be less.
[0040]
Therefore, from this experiment, the presence of an acid-insoluble substance and the Cu contained therein Compound It is suggested that the amount of (y) is deeply related to the re-ignition characteristic.
[0041]
In order to stabilize the re-ignition characteristics and interruption characteristics of vacuum valves, the composition of contact materials, fluctuations in the amount of components, the amount of gas, the structure of the structure (particle size, particle size distribution, degree of segregation, present in the alloy) In addition to the above, the CuCr alloy is dissolved in an acid solution and then not dissolved. Acid insoluble Cu remaining in solution Compound The amount of (y) is deeply involved.
[0042]
Hereinafter, the present invention will be described in detail by way of examples and comparative examples. Evaluation conditions and evaluation results are shown in FIGS.
[0043]
(1) Re-ignition characteristics
A disk-shaped contact piece having a diameter of 30 mm and a thickness of 5 mm was attached to a demountable vacuum valve, and the re-ignition occurrence frequency when a circuit of 24 kv × 500 A was interrupted 2000 times was measured.
[0044]
In addition, the result displayed the re-ignition frequency as follows.
[0045]
That is, when the number of occurrences in Example 2 is 1.0, the magnification is less than 0.1 (A), 0.1 to 0.8 is evaluated (B), and 0.8 to 1.2. Evaluation (C), 1.2 to 1.5 were evaluated (D), 1.5 to 10 were evaluated (X), 10 to 100 were evaluated (Y), and 100 or more were evaluated (Z).
[0046]
The evaluations (A) to (D) were evaluated as “pass”, and the evaluations (X) to (Z) were determined as “bad”.
[0047]
(2) Interrupting characteristics
A break test test valve with a 70 mm diameter contact is attached to the switchgear, and after baking, voltage aging, etc., it is connected to a 24 kv, 50 Hz circuit, and the break limit is reduced while increasing the current by approximately 1 kA. Three valves were evaluated. In addition, the numerical value showed the comparative value when the value of Example 2 was set to 1.0 with the variation width.
[0048]
(3) Outline of assembly of test valve for shut-off test
An outline of the assembly of the test valve for shut-off test is shown. Ceramic insulation container with an average end surface roughness of about 1.5μm (main component: AL ₂ O _Three The ceramic insulating container was preheated at 1600 ° C. before assembly. A 42% Ni—Fe alloy having a thickness of 2 mm was prepared as a sealing metal fitting. A 72% Ag—Cu alloy plate having a thickness of 0.1 mm was prepared as a brazing material. Each of the prepared members is disposed between the objects to be joined (the end face of the ceramic insulating container and the sealing metal fitting) so as to be hermetically sealed and bonded. ^-Four It was subjected to a hermetic sealing process between the sealing metal fitting and the ceramic insulating container in a vacuum atmosphere of Pa.
[0049]
(4) Acid insoluble Cu in contact alloys Compound Quantification of (y)
The quantitative determination of the acid-insoluble Cu in the alloy contained in the contact material was performed, for example, by the following method. After adding nitric acid to the miniaturized CuCr contact, the filtrate (Cu phase) and the precipitate A are separated. The filtrate (Cu phase) in this case corresponds to the acid-soluble Cu component (x). The precipitate A is separated into a filtrate (Cr) and a precipitate B by acid dissolution and dissolution. The acid non-dissolved substance (y) is known by quantifying the precipitate A with an analyzer such as ICP-AES.
[0050]
(Examples 1-4, Comparative Examples 1-2)
In the present invention, re-ignition characteristics, interruption characteristics, and acid insoluble Cu contained in the contact material Compound The relationship with (y) is important.
[0051]
Cu insoluble in acid Compound The amount of (y) was quantified under the following conditions.
[0052]
A Cu-25% Cr alloy was selected as the representative contact, and about 10 gr. Were collected. For example, 3N (normative) HNO at 100 ° C _Three After about 10 minutes of thermal decomposition, the solution is filtered and separated into filtrate A and precipitate A.
[0053]
In filtrate A, HNO _Three Cu (Cu ²⁺ ) And HNO _Three There is a trace amount of Cr dissolved in. The amount of Cu (x) and the amount of Cr (b) dissolved in the filtrate A are quantified by ICP-AES or the like. The value of (x) corresponds to the Cu phase in the contact material after sintering.
[0054]
Precipitate A contains HNO _Three Cu (y) not dissolved in HNO and HNO _Three And Cr (c) that does not dissolve in. The amount of Cu (y) and the amount of Cr (c) in the precipitate A are quantified by ICP-AES or the like.
[0055]
From the above analysis, it is possible to easily know the amount of Cr (b) dissolved in the acidic solution important in the present invention and the amount of Cu (y) not dissolved in the acidic solution. Further, as an auxiliary finding, the amount of Cu (x) dissolved in the acidic solution and the amount of Cr (c) not dissolved in the acidic solution can be easily known.
[0056]
For reference, the precipitate A was thermally decomposed with 6N HCl (at 100 ° C. for 30 minutes), filtered, and filtrate B (Cr ³⁺ ) And precipitate B.
[0057]
Here filtrate B (Cr ³⁺ ) Substantially coincides with the 0.1 to 150 μm Cr particles (a) used as a raw material during contact production. The value of (a) is theoretically the sum of the sum of (b) and (c) and the sum of (loss during analysis operation) and (loss during contact manufacturing such as sintering process). is there.
[0058]
For reference, the precipitate B is the HNO _Three It is a substance that does not dissolve in (means not to decompose) and remains in the HCl without further dissolution. This precipitate B is dissolved in an alkaline solution (for example, NaOH) and further dissolved in an acid solution, and a substance that is not dissolved (meaning not to be decomposed) in both solutions is recovered, and ICP -Determine the substance (d) insoluble in acid and alkaline solutions by quantitative analysis such as with AES. (D) is mainly caused by the raw material Cr ₂ O _Three Etc.
[0059]
For example, by selecting the treatment atmosphere and its quality, treatment temperature, time, cooling conditions, adjustment of raw material powder (Cu, Cr), etc., acid insoluble Cu in the contact material Compound A material having an amount of (y) in the range of less than 10 ppm and in the range of 10 ppm to 6000 ppm was produced and subjected to the test (Comparative Examples 1-2, Examples 1-4).
[0060]
That is, as a representative contact for evaluation, a Cu-25% Cr alloy subjected to heat treatment at 1060 ° C. was selected for a molded body of Cu powder and Cr powder, and the quantification method described above for these contact alloys Acid-insoluble Cu contained in the contact material Compound The amount of (y) is less than 10 ppm (Comparative Example 1), 10 ppm (Example 1), 30-50 ppm (Example 2), 100-300 ppm (Example 3), 900-1000 ppm (Example 4), 5600 A product of ˜6000 ppm (Comparative Example 2) was produced.
[0061]
Evaluation of re-ignition characteristics is less than 0.1 times when the number of occurrences of re-ignition in Example 2 when the circuit of 24 kv × 500 A is interrupted 2000 times for each contact is 1.0 (A) , 0.1 to 0.8 times as evaluation (B), 0.8 to 1.2 as evaluation (C), and 1.2 to 1.5 times as evaluation (D), and these are judged as “pass” Then, 1.5 to 10 times were evaluated as (X), 10 to 100 times as evaluation (Y), and 100 times or more as evaluation (Z), and these were judged as “bad”.
[0062]
The breaking characteristics were evaluated by measuring the breaking current value for each contact and by multiplying the breaking current value of Example 2 described later to 1.0.
[0063]
[Evaluation result of re-ignition characteristics (frequency of re-ignition)]
Acid-insoluble Cu contained in contact material Compound When the amount of (y) is 10 ppm (Example 1), it is less than 0.1 times and 0.1 to 0.8 times higher than the occurrence frequency of Example 2 to be described later. (Evaluations (A) to (B)) were demonstrated.
[0064]
Acid insoluble Cu Compound When the amount of (y) was 30 to 50 ppm (Example 2), it showed 0.8 to 1.2 times and exhibited extremely good re-ignition characteristics (evaluation (C)).
[0065]
Acid insoluble Cu Compound When the amount of (y) is 100 to 300 ppm (Example 3), it shows 0.8 to 1.2 times the occurrence frequency of Example 2, and good re-ignition characteristics (evaluation (C)) Demonstrated.
[0066]
Acid insoluble Cu Compound When the amount of (y) is 900 to 1000 ppm (Example 4), it is within 1.2 to 1.5 times compared with the occurrence frequency of Example 2, and good re-ignition characteristics (evaluation (C) To (D)).
[0067]
In contrast, acid-insoluble Cu Compound In 5600 to 6000 ppm (Comparative Example 2), the amount of (y) is larger than those in Examples 1 to 4, compared with the occurrence frequency of Example 2 as a standard, 10 to 100 times and 100 times or more The arc occurrence frequency (evaluations (Y) to (Z)) is not preferable.
[0068]
As described above, acid insoluble Cu Compound When the amount of (y) is 1000 ppm or less, favorable re-ignition characteristics are seen, whereas acid-insoluble Cu Compound When the amount of (y) is 5600 ppm (Comparative Example 2), which is larger than that of Example 4, the insulation recovery immediately after the interruption is remarkably slow, and re-ignition occurs frequently due to a decrease in withstand voltage. The frequency (evaluation (Y)-(Z)) was shown and the re-ignition characteristic fell remarkably.
[0069]
Clearly acid-insoluble Cu contained in the contact material Compound Good re-ignition characteristics are exhibited when the amount of (y) is below a predetermined amount.
[0070]
In addition, at less than 10 ppm (Comparative Example 1), the re-ignition characteristic exhibits the same evaluation (A) as that in Example 1, but the acid-insoluble Cu in the contact material. Compound To stably reduce the amount of (y) to less than 10 ppm, the cost is high, the manufacturing process is complicated, and the economic value is low.
[0071]
[Evaluation result of interruption characteristics]
Acid-insoluble Cu contained in contact material Compound When the blocking ratio when the amount of (y) is 30 to 50 ppm (Example 2) is 1.0, the acid-insoluble Cu Compound When the amount of (y) is 10 ppm (Example 1), the blocking magnification is (1.0 to 1.1) times, acid insoluble Cu Compound The blocking ratio when the amount of (y) is 100 to 300 ppm (Example 3) is also (0.95 to 1.0) times, and acid non-soluble Cu Compound The blocking magnification when the amount of (y) is 900 to 1000 ppm (Example 4) is also (0.9 to 0.95) times, which is almost the same as or higher than that of Example 2 as a standard. It is in the preferable cutoff characteristic.
[0072]
In contrast, acid-insoluble Cu Compound When the amount of (y) was 5600 to 6000 ppm (Comparative Example 2), which was larger than that of Examples 1 to 4, the cutoff magnification was reduced to (0.8 to 0.95) times. Obviously acid insoluble Cu in the contact material Compound When the amount of (y) increases, the cutoff characteristic tends to be lowered.
[0073]
In addition, if it is less than 10 ppm (Comparative Example 1), the interruption characteristic exhibits (1.0 to 1.1) times equivalent to that of Example 1, but the acid-insoluble Cu in the contact material. Compound To stably reduce the amount of (y) to less than 10 ppm, the cost is high, the manufacturing process is complicated, and the economic value is low.
[0074]
Therefore, the acid insoluble Cu contained in the contact material Compound The amount of (y) is preferably 1000 ppm or less, and the lower limit is determined by economics as in the case of the re-ignition.
[0075]
(Examples 5-7, Comparative Examples 3-4)
In Examples 1-4 and Comparative Examples 1-2, the acid-insoluble Cu contained in the contact material Compound The effect of the amount of (y) on the re-ignition characteristics and the breaking characteristics was shown for a Cu-25% Cr contact in which the amount of Cu in the contact alloy was 75 wt% (hereinafter referred to as wt% for the contact material). The technology of the present invention is not limited to this, and the effect is exhibited even in cases other than the Cu-25% Cr contact point. That is, 5% Cu—Cr (Comparative Example 3), 10% Cu—Cr (Example 5), 50% Cu—Cr (Example 6), and 85% Cu—Cr with 5% Cu in the contact alloy. (Example 7) After producing 98% Cu-Cr (Comparative Example 4), acid non-soluble Cu from these contact materials Compound The evaluation was performed after selecting a contact material having an amount of (y) in the range of 100 to 300 ppm.
[0076]
[Re-ignition characteristics]
When 10% Cu—Cr (Example 5), 50% Cu—Cr (Example 6), and 85% Cu—Cr (Example 7), 0.1 to 0. 8 times and 0.8 to 1.2 times (Evaluations (B) to (C)) are exhibited, and good re-ignition characteristics are exhibited.
[0077]
On the other hand, in 98% Cu—Cr (Comparative Example 4) in which the amount of Cu in the contact is greater than 85% of Example 7, the phenomenon that the welding phenomenon is partially generated and the contact surface roughness is increased when the current is interrupted. It shows 1.5 to 10 and 100 or more (evaluation (X) to (Z)) due to a decrease in the withstand voltage characteristic of the contact, and the re-ignition characteristic shows a large variation and is undesirably lowered significantly.
[0078]
In the case of 5% Cu—Cr (Comparative Example 3) in which the amount of Cu in the contact is 5%, the re-ignition characteristics are equal to or higher than those of the standard sample (Example 2). The frequency of occurrence is 0.1 to 8 times and 0.8 to 1.2 times (evaluations (B) to (C)), and exhibits good re-ignition characteristics.
[0079]
As described above, the amount of Cu contained in the contact material to which the present invention technique is applied is preferably 85% or less.
[0080]
[Interruption characteristics]
As for the breaking characteristics, the amount of Cu in the contact is 10% Cu—Cr (Example 5) is (0.9 to 0.95) times larger, and the rate of 50% Cu—Cr (Example 6) is ( 1.0) and 85% Cu—Cr (Example 7) have a cutoff magnification of (1.0 to 1.1) times, which is almost the same as that of Example 2 as a standard.
[0081]
The interruption ratio of 5% Cu—Cr (Comparative Example 3) in which the amount of Cu in the contact is less than 10% of Example 5 is (0.55 to 0) by reducing the electrical conductivity of the contact material itself (8% IACS or less). .7) Doubled, showing a significant drop and a large variation.
[0082]
On the other hand, 98% Cu—Cr (Comparative Example 4) having a Cu amount in the contact larger than 85% of Example 7 shows (0.7 to 1.15) times higher than that of Example 7, and the contact surface is rough. Due to this, the cutoff characteristics varied greatly.
[0083]
From the above, it is preferable to use a contact in the range of 10 to 85% by weight of Cu contained in the contact material to which the present invention technique is applied.
[0084]
That is, when the Cu content of the contact alloy is less than 10% by weight, the interruption characteristic is greatly lowered due to the low conductivity of the contact material itself. In addition, the contact resistance, circuit resistance, and temperature increase are increased, resulting in a decrease in the cutoff current value and a decrease in the rated switching current value. When the amount of Cu exceeds 85% by weight, the arc resistance is inferior when the current is interrupted, and the contact surface after the interruption is markedly rough, and this roughness is one of the causes of re-ignition.
[0085]
Further, from the viewpoint of the conductivity of the contact material, an alloy having a conductivity of at least 10% IACS is preferable (Examples 5 to 7). In the case where the conductivity is less than 10% IACS, that is, in Comparative Example 3 where the conductivity is 8% IACS or less, the re-ignition characteristic is not changed, but the interruption characteristic is deteriorated.
[0086]
(Examples 8 to 9)
In Examples 1 to 7, an example in which Cu is selected as the conductive component in the contact material has been described. However, the technology of the present invention is not limited to this, and the effect is exhibited even when other than Cu.
[0087]
That is, even with 40% Ag-Cr (Example 8) in which the conductive component in the contact material is Ag, the re-ignition frequency is 1.2 to 1.5 times as good as the re-ignition characteristics ( It shows the evaluation (D)) and is in the pass range.
[0088]
Furthermore, even in the case of 75% (Ag + Cu) -Cr (Example 9) in which the conductive component is Ag = 54% and Cu = 21%, the frequency of occurrence of re-ignition is 0.8 to 1.2 times and The re-ignition characteristic (evaluation (C)-(D)) of 1.2 to 1.5 times is shown and it is the range of a pass.
[0089]
The interruption characteristics are (0.9) times (Example 8) and (0.95 to 1.05) times (Example 9) when the interruption characteristic of Example 2 as a standard is 1.0. Both of these are acceptable ranges.
[0090]
As described above, even when a part or all of the conductive component, that is, the Cu matrix is replaced with Ag, the same characteristics as those of the Cu matrix are exhibited.
[0091]
(Examples 10-12, Comparative Examples 5-6)
In Examples 1-9 and Comparative Examples 1-4, the acid-insoluble Cu in the contact alloy that affects the re-ignition characteristics and the interruption characteristics Compound The influence of the amount of (y) was shown for the contact with the amount of Cr (b) dissolved in the Cu matrix in the contact alloy as 0.02% (weight%). The amount of (b) is not limited to 0.02% and exhibits its effect.
[0092]
That is, 75% Cu—Cr (Examples 10 to 12) in which the amount of Cr (b) dissolved in the Cu matrix in the contact alloy was 0.005%, 0.1%, and 0.5%, And 75% Cu—Cr (Comparative Example 5) of less than 0.005% and 75% Cu—Cr (Comparative Example 6) of more than 0.5%, mainly cooling process during contact manufacturing After adjusting the cooling rate in the above, the acid insoluble Cu in the contact material is selected from these Compound A contact material having an amount of (y) in the range of 100 to 300 ppm was selected and evaluated.
[0093]
[Re-ignition characteristics]
When the amount of arc-resistant component dissolved in the conductive component, that is, the amount of Cr (b) dissolved in the Cu matrix is 0.005%, which is less than 0.02% of Example 2 (Example 10) ) Showed re-ignition characteristics (evaluations (A) to (B)) of less than 0.1 times and 0.1 to 0.8 times better than Example 2. In the case where the amount of Cr (b) dissolved in the Cu matrix is 0.1% (Example 11) and 0.5% (Example 12), both are 0.8 to 1.2. Double (evaluation (C)) was shown, and a preferable re-ignition characteristic was shown.
[0094]
On the other hand, when the amount of Cr (b) dissolved in the Cu matrix is more than 0.5% (Comparative Example 6), 0.8 to 1.2 times to 10 to 100 times (evaluation ( C) to (Y)), showing a re-ignition characteristic with a large variation width, which is not preferable.
[0095]
On the other hand, in Comparative Example 5 in which the amount of Cr (b) dissolved in the Cu matrix was less than 0.005% of Example 10, it was less than 0.1 times the same as Example 10 described above and 0.1 to 0.1%. It was 0.8 times (evaluations (A) to (B)) and was good. However, in this case, the production cost is high and the supply ability is difficult, and from the viewpoint of production technology, it is excluded from the preferred range of the present invention.
[0096]
[Interruption characteristics]
The amount of Cr (b) dissolved in the Cu matrix is less than 0.02% (Example 2) and 0.005% (Example 10) has a cutoff ratio of (1.0 to 1.1) times. , (B) is 0.1% (Example 11), the blocking magnification is (0.9 to 1.0) times, and (b) is 0.5% (Example 12), the blocking magnification is (0.9-0.95) times are shown, and all are good ranges.
[0097]
On the other hand, in Comparative Example 6 in which the amount of Cr (b) dissolved in the Cu matrix is larger than 0.5% of Example 12, the cutoff characteristic is (0.6 to 0.75) times. It is lowered and not preferable.
[0098]
From the above, in carrying out the present invention, the contact alloy in which the amount of Cr (b) dissolved in the Cu matrix in the contact alloy is in the range of 0.005 to 0.5% by weight should be selected. Is preferred.
[0099]
That is, if the amount of Cr (b) to be dissolved in the Cu matrix exceeds 0.5% by weight, there is a problem in terms of economy in terms of contact manufacturing technology, and the conductivity of the contact alloy itself decreases. The shut-off characteristics are greatly reduced. Also, it is not advantageous industrially or economically to control the amount of Cr (b) dissolved in the Cu matrix to less than 0.005% by weight.
[0100]
(Examples 13 to 14, Comparative Example 7)
In Examples 1 to 12 and Comparative Examples 1 to 6, the effects on the re-ignition characteristics and the interruption characteristics were shown for CuCr contacts in which Cr was selected as the type of arc-proof component in the contacts. It is not limited to Cu—Cr contacts, and the effect is exhibited.
[0101]
[Re-ignition characteristics]
That is, the amount of Cr (b) dissolved in the Cu matrix in the contact alloy is 0.02%, and the acid-insoluble Cu contained in the contact material Compound The amount of (y) is 100 to 300 ppm and the balance is Cu, and the types of arc resistance components (weight ratio) present in the contact material are CrW (Cr: W = 9: 1), CrW ( Preferred re-ignition characteristics (evaluation (A) to (B) to evaluation (B) to (C)) equal to or higher than that of Example 2 as a standard even when replaced with Cr: W = 5: 5) (Examples 13 to 14).
[0102]
However, when the ratio of Cr and W is Cr: W = 2: 8, when the Cr component is small, the re-ignition occurrence frequency is 0.8 to 1.2 times and 1.5 to 10 times. The re-ignition characteristics (evaluations (C) to (X)) with a large variation between them were shown (Comparative Example 7).
[0103]
[Interruption characteristics]
In Example 13 of CrW (Cr: W = 9: 1), (0.9 to 1.1) times, also in Example 14 of CrW (Cr: W = 5: 5), (0.9 to 1.. 1) Doubled good blocking characteristics.
[0104]
However, as in the case of Cr: W = 2: 8, when the Cr component in the arc resistant component is small, the interruption characteristic is (0.4 to 0.55) times due to the influence of a large amount of thermionic emission. Decreased significantly. In this case, the insulation recovery immediately after the interruption was significantly delayed, the re-igniting characteristics were varied due to a decrease in the withstand voltage, and the interruption characteristic was also greatly reduced (Comparative Example 7).
[0105]
(Examples 15 to 18)
[Re-ignition characteristics]
The amount of Cr (b) dissolved in the Cu matrix in the contact alloy is 0.02%, and the acid-insoluble Cu contained in the contact material Compound The amount of (y) is 100 to 300 ppm and the balance is Cu, and the types of arc resistance components (weight ratio) present in the contact material are CrMo (Cr: Mo = 9: 1), CrTa ( Cr: Ta = 9: 1), even if replaced with CrNb (Cr: Nb = 9: 1), the re-ignition characteristics (evaluations (A) to (B)) equal to or higher than the standard example 2 are obtained. (Examples 15, 17-18).
[0106]
[Interruption characteristics]
The types of arc resistant components (weight ratio) present in the contact material are CrMo (Cr: Mo = 9: 1), CrTa (Cr: Ta = 9: 1), CrNb (Cr: Nb = 9: 1). Even if it is replaced, it shows a favorable cutoff characteristic (0.95 to 1.15) times equal to or higher than that of the standard example 2 and is a good characteristic (examples 15 and 17 to 18).
[0107]
<Example 16>
In Examples 1 to 14 above, Cr was selected as the type of arc-resistant component dissolved in the conductive component (Cu matrix) in the contact alloy, but in the conductive component (Cu matrix) in Example 16 The type of the arc-proof component dissolved in is CrTi. Even in this case, the effect is exhibited. That is, 75% Cu—Cr (Example 16) was manufactured by setting (CrTi) as the arc resistant component dissolved in the conductive component in the contact alloy and 0.02 as the amount, and the evaluation was performed.
[0108]
[Re-ignition characteristics]
The frequency of re-ignition is less than 0.1 times and 0.1 to 0.8 times (evaluations (A) to (B)) equal to or greater than in Example 2, and exhibits good re-ignition characteristics. ing.
[0109]
[Interruption characteristics]
The blocking characteristics also show the blocking magnification (0.95 to 1.15) times, and are in the same range as in Example 2.
[0110]
From the above, the arc resistance component in the contact can obtain the same effect even if a part of Cr is replaced with one of W, Mo, Ta, Nb and Ti of 50 wt% or less (Example 13). To 18).
[0111]
That is, by replacing a part of Cr with one of W, Mo, Ta, Nb, and Ti, the mechanical strength of the entire Cu—Cr contact material is increased, and the drop of Cr grains is triggered. Re-ignition generation can be reduced.
[0112]
(Examples 19-20, Comparative Examples 8-9)
In Examples 1 to 18 and Comparative Examples 1 to 7, when the particle diameter of the arc resistant component (Cr, CrW, etc.) in the Cu matrix is set to 40 to 80 μm, the effect on the re-ignition characteristics and the interruption characteristics is obtained. Although shown, the particle diameter of the arc resistant component used in the technology of the present invention is not limited to this and exhibits its effect.
[0113]
That is, the amount of Cr (b) dissolved in the Cu matrix in the contact alloy is 0.02%, and the acid-insoluble Cu contained in the contact material Compound After the amount of (y) was 100 to 300 ppm and the balance was Cu, the same evaluation as above was performed.
[0114]
[Re-ignition characteristics]
Even if the particle diameter of the arc-resistant component (Cr) is 0.1 to 25 μm and 70 to 150 μm, preferable re-ignition characteristics (evaluations (B) to (C) and Evaluation (C) to (D)) was shown (Examples 19 to 20).
[0115]
However, when the particle diameter of the arc-resistant component (Cr) in the Cu matrix is less than 0.1 μm, preferable re-ignition characteristics (evaluations (A) to (B)) higher than that of Example 2 as a standard. However, it is excluded from the present invention due to high production costs such as low productivity for making the particle diameter of the arc resistant component (Cr) less than 0.1 μm (Comparative Example 8).
[0116]
In the contact having an average particle diameter of more than 150 μm, the frequency of re-ignition compared with the standard example 2 is 1.5 to 10 times and 100 times or more (evaluation (X) to (Z)), A large drop and a large variation width are shown (Comparative Example 9).
[0117]
[Interruption characteristics]
Even when the particle diameter of the arc-resistant component (Cr) is 0.1 to 25 μm and 70 to 150 μm, (0.95 to 1.05) times and (1.0 to 1.1) times are shown, and the standard implementation It is a preferable value substantially equivalent to the cutoff characteristic 1.0 of Example 2 (Examples 19 to 20).
[0118]
However, the blocking magnification at the contact having an average particle diameter exceeding 150 μm is (0.75 to 1.0) times, and also shows a large variation width, which is not preferable (Comparative Example 9).
[0119]
From the above, it is preferable that the arc resistant component in the contact has an average particle diameter of 0.1 to 150 μm.
[0120]
(Examples 21 to 26, Comparative Example 10)
In Examples 1 to 20 and Comparative Examples 1 to 9, CuCr contacts that do not contain auxiliary components such as Bi for improving welding resistance in the contact alloys have an effect on re-ignition characteristics and interruption characteristics. Although shown, the present invention is not limited to this, and even if an auxiliary component such as Bi is present within a predetermined amount in the above contact alloy, the effect is maintained.
[0121]
That is, 75% Cu—Cr alloy with 0.1% and 1.0% Bi added to the contact alloy (Examples 21 to 22), and 75% Cu—Cr alloy with 2.0% Bi added (Comparison) Example 10), 75% Cu—Cr alloy added with 0.3% Pb (Example 23), 75% Cu—Cr alloy added with 0.1% Sb (Example 24), Te 3.0% A 75% Cu—Cr alloy (Example 25) added and a 75% Cu—Cr alloy (Example 26) added with 1.0% Se were manufactured, and the same evaluation as described above was performed.
[0122]
[Re-ignition characteristics]
The frequency of re-ignition was 0.1 to 0.8 times and 0.8 to 1.2 times (evaluation (B) to (C)) in Example 21 in which the Bi amount was 0.1%, Bi In Example 22 in which the amount was 1.0%, 0.8 to 1.2 times and 1.2 to 1.5 times (evaluations (C) to (D)) were shown, which were almost the same as those in Example 2 or The above preferred re-ignition characteristics are shown.
[0123]
However, in Comparative Example 10 in which the Bi amount is 2.0%, 10 to 100 times (evaluation (Y)) and 100 times or more (evaluation (Z)) are shown. Enlargement is seen, which is not preferable. Note that the presence of Bi significantly improves the welding resistance as compared with Example 2.
[0124]
[Interruption characteristics]
The cut-off characteristics are (0.95) times in Example 21 in which the Bi amount is 0.1%, and (0.9) times in Example 22 in which the Bi amount is 1.0%. The characteristics were almost the same as in Example 2.
[0125]
On the other hand, in Comparative Example 10 in which the Bi amount was 2.0%, the re-ignition characteristic was evaluated as a result of the deterioration of the withstand voltage due to the contact surface roughness caused by the selective evaporation of Bi generated at the time of interruption. Y) to (Z) are deteriorated, and the blocking magnification is greatly reduced to (0.3 to 0.45) times, which is not preferable.
[0126]
Example 23 with Pb content of 0.3%, Example 24 with Sb content of 0.1%, Example 25 with Te content of 3.0%, Example with Se content of 1.0% Even in a 75% Cu—Cr alloy containing other welding resistant components such as No. 26, the re-ignition characteristics are 0.8 to 1.2 times (Evaluation (C)) and 1.2 to 1. 5 times (assessment (D)), good re-ignition characteristics, and (0.9) times (Examples 23 to 24) and (0.99 to 0.95) times the blocking magnification ( Examples 25 to 26) are shown, showing good blocking characteristics.
[0127]
As described above, the presence of 1% by weight or less of Bi, Pb, and Sb in the CuCr contact stabilizes the contact surface roughness after current interruption and contributes to further lowering the re-ignition occurrence level. However, the presence of Bi, Pb, and Sb exceeding 1% is not preferable because the frequency of re-ignition is increased. The presence of 5% by weight or less of Te and Se also stabilizes the contact surface roughness after current interruption and lowers the level of reignition.
[0128]
(Examples 27-29, Comparative Examples 11-12)
In the practice of the present invention, the conductivity of the current-carrying shaft of the vacuum circuit breaker is usually 100% IACS Cu. However, in the present invention, 95% IACS (Example 27), 70% IACS (Example) 28), the re-ignition occurrence frequency is evaluated (B) to (C), and no change is observed in the re-ignition characteristics, but the conductivity of the conduction shaft is 0.3% of 50% IACS. When the weight% Zr—Cu alloy is used (Comparative Example 11), the interruption characteristic shows (0.5 to 0.65) times the interruption factor, and the interruption characteristic is greatly deteriorated.
[0129]
Therefore, it is preferable that the conductivity of the conducting shaft has a conductivity of at least 70% IACS.
[0130]
That is, if the conductivity of the current-carrying shaft is less than 70% IACS, the circuit resistance is increased, causing an increase in temperature, resulting in a decrease in the cut-off current value and a decrease in the rated switching current value.
[0131]
Pure Cu is inferior in deformation resistance to mechanical external force, but can be used as a suitable current-carrying shaft material because the conductivity of 100% IACS can be easily obtained by performing design considerations. .
[0132]
In the practice of the present invention, the coil electrode of the vacuum circuit breaker is usually made of 100% IACS Cu. However, in the present invention, the coil electrode is 70% IACS made of 0.1 wt% Cr—Cu. Even in Example 29, the re-ignition occurrence frequency is the evaluation (B) to (C), and the re-ignition characteristics are not changed. When a 0.3 wt% Zr—Cu alloy having a coil electrode conductivity of 50% IACS is used (Comparative Example 12), the interruption characteristic shows (0.4 to 0.55) times the interruption magnification. A significant decrease in the blocking characteristics is observed.
[0133]
Therefore, the coil electrode preferably has a conductivity of at least 70% IACS.
[0134]
That is, if the conductivity of the coil electrode is less than 70% IACS, the circuit resistance is also increased, resulting in an increase in temperature, resulting in a decrease in the cut-off current value and a decrease in the rated switching current value.
[0135]
Pure Cu is inferior in deformation resistance to a mechanical external force, but can be used as a suitable coil electrode material because it can easily obtain a conductivity of 100% IACS by performing design considerations.
[0136]
【The invention's effect】
As described above, according to the vacuum circuit breaker of the present invention, both the re-ignition characteristic and the interruption characteristic can be achieved.
[Brief description of the drawings]
FIG. 1 is a table showing evaluation conditions of Examples 1 to 9 and Comparative Examples 1 to 4 of a vacuum circuit breaker according to the present invention.
FIG. 2 is a table showing the evaluation conditions of Examples 10 to 20 and Comparative Examples 5 to 9 of the vacuum circuit breaker according to the present invention.
FIG. 3 is a table showing the evaluation conditions of Examples 21 to 29 and Comparative Examples 10 to 12 of the vacuum circuit breaker according to the present invention.
FIG. 4 is a table showing evaluation results of Examples 1 to 9 and Comparative Examples 1 to 4 of the vacuum circuit breaker according to the present invention.
FIG. 5 is a table showing evaluation results of Examples 10 to 20 and Comparative Examples 5 to 9 of the vacuum circuit breaker according to the present invention.
FIG. 6 is a table showing evaluation results of Examples 21 to 29 and Comparative Examples 10 to 12 of the vacuum circuit breaker according to the present invention.
FIG. 7 is a cross-sectional view showing a configuration example of a typical vacuum circuit breaker.
FIG. 8 is a cross-sectional view showing another configuration example of a typical vacuum circuit breaker.
[Explanation of symbols]
101 ... Insulating container
102a, 102b ... lid
103 ... Vacuum container
104, 105 ... Contact
106, 107 ... energizing shaft
108 ... Bellows
109 ... Arc shield
M: Movement direction of the energizing shaft 107
40, 50 ... Flat plate electrode or coil electrode
41, 51 ... Contact

Claims

真空容器と、ベローズと、通電軸と、対向する一対の接点とを備えた真空遮断器において、前記接点は１０〜８５重量％のＣｕより成る導電性成分と、残部が０．１〜１５０μｍの平均粒子直径を持つ９０〜１５重量％のＣｒより成る耐弧性成分とを含有するＣｕ−Ｃｒ系接点合金から成り、前記合金中のＣｕマトリックスにおける酸性溶液に溶解しないＣｕ化合物である酸非溶解性Ｃｕ化合物の量が１０ｐｐｍ〜１０００ｐｐｍであることを特徴とする真空遮断器。In a vacuum circuit breaker including a vacuum vessel, a bellows, a current-carrying shaft, and a pair of opposing contacts, the contact is a conductive component made of 10-85 wt% Cu, and the balance is 0.1-150 μm. Acid-insoluble, which is a Cu compound, which is a Cu-compound contact alloy containing an arc-resistant component composed of 90 to 15% by weight of Cr having an average particle diameter and not dissolved in an acidic solution in a Cu matrix in the alloy A vacuum circuit breaker characterized in that the amount of the conductive Cu compound is 10 ppm to 1000 ppm.

前記耐弧性成分は、前記９０〜１５重量％のＣｒ量に対して、その一部を５０重量％以下のＷ、Ｍｏ、Ｔａ、Ｎｂ、Ｔｉの少なくとも１つで置換したことを特徴とする請求項１に記載の真空遮断器。Said arc-proof component has a feature in that the relative amount of Cr 90 to 15 wt%, by replacing part of its 50 wt% or less of W, Mo, Ta, Nb, in at least one of Ti The vacuum circuit breaker according to claim 1.

前記Ｃｕマトリックス中に、０．００５〜０．５重量％のＣｒを固溶させたことを特徴とする請求項１または請求項２に記載の真空遮断器。The vacuum circuit breaker according to claim 1 or 2, wherein 0.005 to 0.5 wt% of Cr is dissolved in the Cu matrix.

前記Ｃｕマトリックスの一部又は総てがＡｇであることを特徴とする請求項1乃至請求項３のいずれかに記載の真空遮断器。The vacuum circuit breaker according to any one of claims 1 to 3, wherein a part or all of the Cu matrix is Ag.

前記接点は、補助成分として、１重量％以下のＢｉ、Ｓｂ、Ｐｂの少なくとも1つ、または５重量％以下のＴｅ、Ｓｅの少なくとも1つを含有する接点であることを特徴とする請求項1乃至請求項４のいずれかに記載の真空遮断器。2. The contact according to claim 1, wherein the contact contains at least one of Bi, Sb and Pb of 1% by weight or less or at least one of Te and Se of 5% by weight or less as an auxiliary component. The vacuum circuit breaker according to claim 4.

前記接点は、少なくとも１０％ＩＡＣＳの導電率を持つ合金から成る接点であることを特徴とする請求項1乃至請求項５のいずれかに記載の真空遮断器。6. The vacuum circuit breaker according to claim 1, wherein the contact is a contact made of an alloy having a conductivity of at least 10% IACS.

前記通電軸は、少なくとも７０％ＩＡＣＳの導電率を持つ通電軸であることを特徴とする請求項1乃至請求項６のいずれかに記載の真空遮断器。The vacuum circuit breaker according to any one of claims 1 to 6, wherein the energizing shaft is an energizing shaft having a conductivity of at least 70% IACS.

前記接点の背面にコイル電極を備え、前記コイル電極は、少なくとも７０％ＩＡＣＳの導電率を持つコイル電極であることを特徴とする請求項1乃至請求項７のいずれかに記載の真空遮断器。8. The vacuum circuit breaker according to claim 1, wherein a coil electrode is provided on a back surface of the contact, and the coil electrode is a coil electrode having a conductivity of at least 70% IACS.