JP4035342B2

JP4035342B2 - Rotating electrical terminal box

Info

Publication number: JP4035342B2
Application number: JP2002039926A
Authority: JP
Inventors: 弘幸林; 峯学横
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2002-02-18
Filing date: 2002-02-18
Publication date: 2008-01-23
Anticipated expiration: 2022-02-18
Also published as: JP2003244889A

Description

【０００１】
【発明の属する技術分野】
本発明は、回転電機の端子箱に関する。
【０００２】
【従来の技術】
一般に、回転電機においては、その回転電機のリード線と電源ケーブルとの接続部を端子箱によって覆い、端子部分への人体の接触および雨水や異物の侵入を防ぎ、感電や相間短絡等の事故を防ぐことが行われている。
【０００３】
図６は、回転電機本体に端子箱を取付けた状態を示す斜視図、図７は上記端子箱部の断面図であって、回転電機本体１の側壁に容器状の端子箱２が取付けられ、その端子箱２内においてリード線引き込み部３より引き込まれているリード線４を端子５を介して電源ケーブル６に接続し、その接続部を上記端子箱２により覆うようにしてある。通常端子箱２内では、各相のリード線４、端子５および電源ケーブル６は接続後に絶縁処理を施されているので、各相間の絶縁性は保持されている。
【０００４】
しかしながら、絶縁処理材が剥がれ落ちる等といった何らかの異常な要因により、各相間の絶縁性が失われた場合、相間短絡に至る恐れがある。相間短絡事故が発生すると、その端子間にアーク放電が生じ、その際に発生する熱によってアークの周囲における空気が瞬時かつ極めて急激に膨張するために、端子箱２の内部圧力が急上昇する。この場合、内部圧力上昇により端子箱２が破損し、膨張したガスやアーク、および端子箱の構成材が飛散・噴出して、周辺の機器、および人身に危害を及ぼすこととなる。
【０００５】
これらの問題を防ぐ為に、従来技術として端子箱に放圧装置を取付けることが行われている。この従来の一般的な回転電機の避圧板付きの端子箱の構成と機能について、図８を参照して説明する。図８において、本体部分２ａとカバー部分２ｂからなる端子箱２は、回転電機本体１に取付けられ、リード線引き込み部３から引き込まれたリード線４および電源ケーブル６との接続のための端子５を覆っている。接続部が揺れないよう、リード線４および電源ケーブル６の少なくともどちらか一方を保持するために、固定クランプ７を設ける場合もある。８はカバー部分２ｂを本体部分２ａに取付けるための取付ボルトである。
【０００６】
上記放圧装置９は端子箱２の何れかの壁面に取付けられており、板状の避圧板１０と額縁状の押え板１１および固定ボルト１２によって構成されている。端子箱２の避圧板１０の取付部には避圧板１０よりひと回り小さい穴２ｃが形成されており、避圧板１０の強度は端子箱２の他の壁面よりも小さくなっている。
【０００７】
しかして、相間短絡事故等の原因によりアークが発生し、端子箱２の内部圧力が上昇した場合、端子箱２の他の構成材が破損するよりも前に避圧板１０が破裂し、内部圧力を放圧させることにより、端子箱全体の破壊損傷、飛散を防ぐことができる。
【０００８】
上述のほか、放圧装置を有する回転電機の端子箱の従来例としては実公昭６２−６８４０号公報記載のように、避圧板が回転電機本体の内部に破裂する構成にしたものも提案されている。
【０００９】
【発明が解決しようとする課題】
しかしながら、上述の図８に示すようなものにおいては、周囲の機器や人身への危害を防止するのに不十分な点がある。
【００１０】
すなわち、回転電機の多くは、他の機械と組み合わせて使用する構成上、人が歩き回るのとほぼ同じ高さ位置に設置されているので、回転電機の側面に設けられることの多い端子箱も、人身とほぼ同じ高さ位置に配置される可能性が非常に高い。したがって、もし端子箱に取付けられた避圧板のすぐ脇に人が居た場合、短絡事故等で避圧板が作用すると、開口部から出たガスやアークが直接人身に向かうため、危険性が大きい等の問題がある。
【００１１】
配電盤や開閉器は、回転電機の端子箱よりもその構造が概して複雑で、内部に隔壁や機器取付用の補強材や柱を備えている場合が多いが、回転電機の端子箱は図８にも示したように、本体の構成はごく単純であり、また安価であることが求められる場合が多い。よって、回転電機の端子箱と配電盤や開閉器等とでは、その筐体の強度が大きく異なっており、一般的には回転電機の端子箱の方が筐体の強度が小さい。
【００１２】
以上のことから、回転電機の端子箱に放圧装置を設ける場合、内部圧力により端子箱本体が破損するよりも前に、避圧板が短時間で瞬時かつ一気に破裂し、膨張ガスを速やかに排出することに留意しなければならない。また、図８に示した従来の放圧装置付の回転電機の端子箱の避圧板においては、端子箱の内圧が上昇し避圧板が破裂した際に、破裂した避圧板の破片や端子箱の構成材が飛散して、周辺の機器および人身に危害を及ぼすという課題に対する考慮が不十分という問題があった。
【００１３】
さらに、実公昭６２−６８４０号公報記載の回転電機の端子箱では、避圧板が回転電機本体の内部に破裂する構成としているため、相間短絡事故の際、避圧板の破片や端子箱の構成材が、周辺の機器および人身に向かって直接飛散し危害を及ぼすということはない。しかしながら、この例を採用する場合、端子箱、回転電機本体の双方の取付部を、放圧装置がない通常の製品よりも大きくし、特別の寸法形状とする必要があり、例えば既存の回転電機に対し改善を実施することが困難という問題がある。
【００１４】
更に、図８の従来例において、内圧上昇時に避圧板が容易に破裂することを目的に、板厚を薄くする等して避圧板の強度を小さくした場合、物が当たる等の外的要因によって、簡単に避圧板が割れてしまうという課題があった。
【００１５】
回転電機の規格には、例えばＡＳ２３８０−１（１９８９）の第５．２．１項のような規定がある。その具体的な内容は例えば「装置の最も脆弱な部分に対し、先端が２５ｍｍの半球で質量が１ｋｇの物体を７０ｃｍの高さから落下させて当てても、破損しないこと」といった、いわゆる衝撃試験に関するもので、当然その数値は使用条件により異なってくる。ここで挙げた例は国際規格ではない故に、「どの部分に物が当っても壊れないこと」という仕様の有無は、製造者と使用者間の協議結果によるが、こうした要求があった場合、図８の従来例で示した避圧板のみの構造では、外側からの負荷に対し弱く、すぐに割れてしまうという問題があった。逆にもし避圧板の強度を外的負荷に耐えられるように強くすれば、端子箱の内圧上昇時に即座に避圧板が破裂しなくなってしまい、本来の機能を果たさなくなる。
【００１６】
本発明は、このような点に鑑み、回転電機の端子箱において相間短絡アークが発生した際、放圧装置の働きにより内圧上昇を原因とする端子箱構成材の破損・飛散を防止するのみならず、放圧時はアークの噴出や端子箱の構成材等の飛散により周囲の機器あるいは人身に及ぼす危害を減らし、安全性が高い端子箱を得ることを目的とする。
【００１７】
【課題を解決するための手段】
請求項１に係る発明は、回転電機のリード線及びそのリード線を電源ケーブルに接続する接続端子を覆うように上記回転電機に装着された端子箱であって、
上記端子箱のうち、上記回転電機のリード線引き出し部が設けられている側面に対向するとともにその側面から離間している側壁に、
その避圧板の面積Ａと上記端子箱の容積Ｖとの比Ａ／Ｖの値が０．２以上となる面積を有する避圧板が取り付けられた放圧装置が設けられていることを特徴とする。
【００１８】
請求項２に係る発明は、回転電機のリード線及びそのリード線を電源ケーブルに接続する接続端子を覆うように上記回転電機に装着された端子箱であって、
上記端子箱の側壁には、避圧板が取り付けられた放圧装置と、当該放圧装置の避圧板の外周部分から当該避圧板を囲うように延設された筒状の保護カバーと、当該保護カバーの先端開口部分に設けられて前記避圧板の破片や前記端子箱の内部の構成部材が遠方に飛散しないようにする保護網と、が設けられていることを特徴とする。
【００１９】
また、請求項３に係る発明は、請求項１または２に係る発明において、上記放圧装置の避圧板の少なくとも一面にワニスまたはレジン等を塗布したことを特徴とする。
【００２０】
【発明の実施の形態】
以下、添付図面を参照した本発明の実施の形態について説明する。
図１は本発明の第１の実施の形態を示す図であり、回転電機本体１の側壁に、本体部分２ａとカバー部分２ｂからなる容器状の端子箱２が取付けられており、その端子箱２内においてリード線引き込み部３より引き込まれているリード線４を端子５を介して電源ケーブル６に接続し、その接続部を上記端子箱２により覆うようにしてある。
【００２１】
放圧装置９は図８の従来例のように端子箱の任意の位置ではなく、前記回転電機１のリード線引き出し部１ａが設けられている側面側と対向するとともに上記回転電機の側面から離間している側壁に取り付けられている。また避圧板１０を大きくし、破裂時には大きな開口面積を形成するようになっている。
【００２２】
端子５または他の導電部分において相間短絡が発生（例えばＵ、Ｖ相の短絡）すると、従来例で述べたと同様にアーク放電により端子箱２の内部圧力が急激に上昇する。このとき、上で述べた従来例と本発明との違いにより、より低い内圧上昇で、かつ相間短絡発生からより短時間で避圧板１０が破裂する。こうして、端子箱２は場合によっては多少変形するものの、端子箱２の押え板１１や取付ボルト１２が飛散したり、端子箱２が大きく変形して端子箱カバー取付部の隙間が拡がりそこからアークが大きく噴出したり、端子箱２が破損したりすることなく、即ち放圧装置が正常に機能して、端子箱２の内圧が放圧される。しかも、避圧板等の破片は人が入ることができない回転電機本体１と端子箱２との間に飛散するので、人身事故等の発生を防止することができる。
【００２３】
本発明の作用効果を確認するため、以下の試験を行った。
【００２４】
供試品として用いた端子箱２は図１に準ずる形状で、その寸法は表１の通りであり、壁面の材料や板厚、また蓋との結合部など各部の強度が、従来から一般用に製作されてきた端子箱と同等とした。また比較のため各部の寸法や板厚や結合部のボルトの強度などを、従来品と大きく異ならない程度に若干変化させた供試品も用いた。更に避圧板１０の開口面積を大小に変化させたり、避圧板１０の取付位置を変化させた供試品を幾つか準備し、一般的な設置状況、使用状況の下で事故発生時に想定される短絡条件にて、実際に相間短絡試験を実施した。
【００２５】
【表１】

【００２６】
実験の主な結果を、端子箱の容積Ｖ、避圧板の開口部面積Ａと、放圧装置が正常に機能する、しない、との関係をまとめたものを図２に示す。図２に見られるように、放圧装置が正常に機能する条件を「Ａ／Ｖ≧Ｃ（Ｃ：定数）」と数式化することが出来る。具体例として表１の寸法の端子箱においては、今回の試験では、面積Ａ、容積Ｖの単位を各々ｍ^２、ｍ^３として、Ａ／Ｖが０．２より小さくなると、放圧装置は正常に機能しなかった。以上のことから、避圧板の開口面積を大きくするほど、Ａ／Ｖの値が大きくなり、安全性が高まることが示された。
【００２７】
また、放圧装置の取付位置だけを変え、他を同一条件とした試験を行った結果、回転電機１のリード線引き出し部１ａが設けられている側面と対向するとともに上記回転電機の側面から離間した側壁に放圧装置９を取付けた場合に比べ、それ以外の側の面に取付けた場合は、避圧板の破片や端子箱の構成材が、より遠くに飛散していた。以上のことから、回転電機１のリード線引き出し部１ａが設けられている側面と対向するとともに上記回転電機の側面から離間している端子箱側壁に放圧装置を取付けることで、より安全性が高まることが示された。
【００２８】
よって以上の結果から明らかなように、本実施の形態によれば上述の状況において、内部圧力により端子箱本体が破損するよりも前に避圧板が短時間で瞬時かつ一気に破裂し、膨張ガスを速やかに排出することができ、かつ周囲に対する危害をより少なくできるので、従来の端子箱よりも安全性を高めることができる。
【００２９】
なお、本発明の実施の形態においては、放圧装置以外の部分の構造は従来の端子箱とほぼ同等でよいことから、回転電機本体と端子箱の取付部分が既存の端子箱と同一形状でよいため、既存の回転電機に対し本発明の端子箱を取り付ける改善が容易である。
【００３０】
また上述までの説明では、本発明の端子箱を新たに製作することを前提としているが、放圧装置以外の部分の構造は従来の端子箱とほぼ同等でよいことから、既存の端子箱に対し本発明の実施の形態に沿って放圧装置を取付ける改造を行うことによっても、本発明の目的を果たすことが出来る。
【００３１】
また、避圧板１０は板状でなく膜状としてもよい。また、端子箱１と避圧板１０との間、および避圧板１０と押え板１１との間には、防水、防塵のためにパッキンを挿入するかシール材を塗布してもよい。
【００３２】
図３及び図４は、本発明の第２の実施の形態を示す図であって、放圧装置の構成部品である避圧板１０に対し、少なくとも一面にワニスまたはレジン等１３を塗布し乾燥させられている。
【００３３】
しかして、相間短絡事故により端子箱内圧が上昇した場合、圧力を受け避圧板１０が変形すると、塗布し乾燥し固められているワニスまたはレジン等１３の一面に細かく網目状にき裂が入るため、そこを起点に避圧板自体が一気に粉々に破裂し易くなる。よって、より安全性を高めることが出来る。
【００３４】
なお、避圧板にワニスを塗布する際、図４に示すように、避圧板１０の全面に塗布せず中央部のみの塗布としても、同様の効果を得ることが出来る。
【００３５】
さらに、図５は本発明の第３の実施の形態を示す図であって、端子箱２の外側に向かって、避圧板１０の外周部分から避圧板１０を囲う様に筒状の保護カバー１４が設けられており、保護カバー１４の先端の開口部分に、保護網１５が設けられている。そして、端子箱２、保護カバー１４、保護網１５は何れも外からの落下物等の負荷に対し耐えられるだけの構造的強度を持っている。また端子箱２、保護カバー１４は高温に耐えうる熱的な強度も持っている。なお図５では保護カバー１４は避圧板１０の押え板の役割を兼ね備えた構造としているが、これらは別々の部品で構成してもよい。
【００３６】
しかして、相間短絡事故により端子箱２の内圧が上昇した場合、保護カバー１４と保護網１５により、避圧板１０の破片や端子箱内部の構成材の飛散をより少なく抑えられる。
【００３７】
なお、保護網の網目の大きさは、粉々となる避圧板の破片よりも、若干小さい程度とすることで、破片の飛散を更に防ぐことが出来る。但し、端子箱内部で膨張したガスを速やかに排出させるため、網目があまり小さくなり過ぎないようにする。
【００３８】
また、保護カバー１４の向きに配慮し、短絡アーク等を人の居ない方向へ向けることで、事故時に人身に及ぼす危害を更に抑えることもできる。
【００３９】
よって以上の結果から明らかなように、本実施の形態によれば、回転電機の端子箱２に対して「外から落下物がどこに当っても壊れないこと」との仕様を要求された場合でも、保護カバーと保護網により仕様を満足し、かつ放圧装置としての安全性をより高めることが出来る。第２及び第３の実施の形態は、第１の実施の形態と組合わせて用いてもよい。この場合にはさらに安全性を高めることができる。
【００４０】
【発明の効果】
以上説明したように、本発明は回転電機の端子箱において相間短絡アークが発生した際、放圧装置の働きにより内圧上昇を原因とする端子箱構成材の破損・飛散を防止するのみならず、放圧時はアークの噴出や端子箱の構成材等の飛散により周囲の機器あるいは人身に及ぼす危害を減らし、従来の端子箱よりも安全性を高めることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態を示す端子箱の構成図。
【図２】本発明の第１の実施の形態に対する短絡試験の結果を示す特性図。
【図３】本発明の第２の実施の形態を示す端子箱の放圧装置の一例を示す図。
【図４】本発明の第２の実施の形態を示す端子箱の放圧装置の他の例を示す図。
【図５】本発明の第３の実施の形態を示す端子箱の放圧装置の一例を示す図。
【図６】一般的な回転電機の端子箱取付状態を示す斜視図。
【図７】従来の回転電機の端子箱の構成図。
【図８】従来の放圧装置付きの回転電機の端子箱の構成図。
【符号の説明】
１回転電機本体
２端子箱
３リード線引き込み部
４リード線
５端子
６電源ケーブル
７ケーブル固定クランプ
８取付ボルト
１０避圧板
１１避圧板押え板
１２避圧板固定ボルト
１３ワニスまたはレジン等
１４避圧板保護カバー
１５避圧板保護網[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a terminal box for a rotating electrical machine.
[0002]
[Prior art]
Generally, in a rotating electrical machine, the connection between the lead wire of the rotating electrical machine and the power cable is covered with a terminal box to prevent contact of the human body with the terminal part and intrusion of rainwater and foreign matter, and to prevent accidents such as electric shock and short circuit between phases. It has been done to prevent.
[0003]
6 is a perspective view showing a state in which the terminal box is attached to the rotating electrical machine main body, FIG. 7 is a cross-sectional view of the terminal box part, and a container-like terminal box 2 is attached to the side wall of the rotating electrical machine main body 1, The lead wire 4 drawn from the lead wire lead-in portion 3 in the terminal box 2 is connected to the power cable 6 via the terminal 5, and the connection portion is covered with the terminal box 2. In the normal terminal box 2, the lead wires 4, the terminals 5, and the power cable 6 of each phase are subjected to insulation treatment after being connected, so that insulation between the phases is maintained.
[0004]
However, when the insulation between the phases is lost due to some abnormal factors such as the insulation treatment material being peeled off, there is a risk of short-circuiting between the phases. When a phase short-circuit accident occurs, arc discharge occurs between the terminals, and the air generated around the arc expands instantaneously and extremely rapidly due to the heat generated at that time, so that the internal pressure of the terminal box 2 rapidly increases. In this case, the terminal box 2 is damaged due to an increase in internal pressure, and the expanded gas and arc, and the constituent materials of the terminal box are scattered and ejected, causing harm to peripheral equipment and personnel.
[0005]
In order to prevent these problems, a pressure relief device is attached to a terminal box as a conventional technique. The configuration and function of the conventional terminal box with a pressure-proof plate of a general rotating electric machine will be described with reference to FIG. In FIG. 8, a terminal box 2 comprising a main body portion 2 a and a cover portion 2 b is attached to the rotating electrical machine main body 1 and is connected to a lead wire 4 drawn from a lead wire lead-in portion 3 and a power cable 6. Covering. A fixed clamp 7 may be provided to hold at least one of the lead wire 4 and the power cable 6 so that the connection portion does not shake. Reference numeral 8 denotes a mounting bolt for mounting the cover portion 2b to the main body portion 2a.
[0006]
The pressure relief device 9 is attached to one of the wall surfaces of the terminal box 2, and is constituted by a plate-shaped pressure-reducing plate 10, a frame-shaped presser plate 11, and a fixing bolt 12. A hole 2c that is slightly smaller than the pressure-reducing plate 10 is formed in the mounting portion of the pressure-reducing plate 10 of the terminal box 2, and the strength of the pressure-reducing plate 10 is smaller than other wall surfaces of the terminal box 2.
[0007]
Thus, when an arc is generated due to a short circuit accident or the like and the internal pressure of the terminal box 2 rises, the pressure relief plate 10 bursts before the other components of the terminal box 2 are damaged, and the internal pressure By releasing the pressure, destruction damage and scattering of the entire terminal box can be prevented.
[0008]
In addition to the above, as a conventional example of a terminal box of a rotating electric machine having a pressure relief device, a structure in which a pressure relief plate is ruptured inside the rotating electric machine main body has been proposed as described in Japanese Utility Model Publication No. 62-6840. Yes.
[0009]
[Problems to be solved by the invention]
However, what is shown in FIG. 8 described above is insufficient to prevent harm to surrounding equipment and people.
[0010]
That is, many of the rotating electrical machines are installed at almost the same height as people walk around on the configuration used in combination with other machines, so the terminal box that is often provided on the side of the rotating electrical machine, It is very likely to be placed at almost the same height as the human body. Therefore, if there is a person right next to the pressure plate attached to the terminal box, if the pressure plate acts in the event of a short-circuit accident, etc., the gas or arc from the opening will go directly to the human body, which is very dangerous. There are problems such as.
[0011]
Switchboards and switches are generally more complicated in structure than terminal boxes for rotating electrical machines, and are often equipped with bulkheads, equipment mounting reinforcements and pillars inside, but the terminal box for rotating electrical machines is shown in FIG. As shown, the structure of the main body is very simple and is often required to be inexpensive. Therefore, the strength of the casing differs greatly between the terminal box of the rotating electrical machine and the switchboard, switch, etc. Generally, the terminal box of the rotating electrical machine has a lower strength of the casing.
[0012]
From the above, when a pressure relief device is installed in the terminal box of a rotating electrical machine, the pressure relief plate bursts instantly and in a short time before the terminal box body is damaged by the internal pressure, and the inflation gas is quickly discharged. You must keep in mind that. Further, in the conventional pressure relief plate for a rotating electrical machine with a pressure relief device shown in FIG. 8, when the internal pressure of the terminal box rises and the pressure relief plate ruptures, There has been a problem that the consideration of the problem that the constituent materials are scattered and harms the surrounding equipment and human body is insufficient.
[0013]
Furthermore, in the terminal box of the rotating electrical machine described in Japanese Utility Model Publication No. 62-6840, the pressure relief plate is configured to burst into the inside of the rotating electrical machine main body. However, it does not scatter directly to the surrounding equipment and people and cause harm. However, when this example is adopted, it is necessary to make the mounting portions of both the terminal box and the rotating electrical machine main body larger than a normal product without a pressure relief device and to have a special size and shape, for example, an existing rotating electrical machine. There is a problem that it is difficult to implement improvements.
[0014]
Further, in the conventional example of FIG. 8, when the strength of the pressure-reducing plate is reduced by reducing the thickness of the pressure-reducing plate for the purpose of easily rupturing when the internal pressure is increased, external factors such as hitting an object. There was a problem that the pressure relief plate was easily broken.
[0015]
The standard for rotating electrical machines has, for example, a provision as described in Section 5.2.1 of AS2380-1 (1989). The specific content is, for example, a so-called impact test such that “the most vulnerable part of the device does not break even if an object with a hemisphere with a tip of 25 mm and a mass of 1 kg is dropped from a height of 70 cm. Of course, the numerical value varies depending on the use conditions. Since the example given here is not an international standard, the presence or absence of the specification that “any part will not break even if it hits” depends on the result of the discussion between the manufacturer and the user. The structure of only the pressure-reducing plate shown in the conventional example of FIG. 8 has a problem that it is weak against the load from the outside and breaks immediately. On the other hand, if the strength of the pressure relief plate is increased to withstand external loads, the pressure relief plate will not burst immediately when the internal pressure of the terminal box rises, and the original function will not be achieved.
[0016]
In view of these points, the present invention only prevents damage and scattering of the terminal box components caused by the increase in internal pressure due to the action of the pressure release device when a short-circuit arc between phases occurs in the terminal box of the rotating electrical machine. The purpose is to obtain a highly safe terminal box by reducing the danger to the surrounding equipment or human body due to the discharge of arcs and the scattering of the components of the terminal box during pressure release.
[0017]
[Means for Solving the Problems]
The invention according to claim 1 is a lead wire and a terminal box mounted on the rotary electric machine so as to cover the connection terminals for connecting the lead wire to the power cable of the rotary electric machine,
Of the terminal box, on the side wall facing the side surface where the lead wire lead-out portion of the rotating electrical machine is provided and spaced from the side surface,
A pressure relief device is provided to which a pressure relief plate having an area where the ratio A / V of the area A of the pressure relief plate and the volume V of the terminal box is 0.2 or more is attached. .
[0018]
The invention according to claim 2 is a terminal box attached to the rotating electrical machine so as to cover a lead wire of the rotating electrical machine and a connection terminal for connecting the lead wire to the power cable,
On the side wall of the terminal box, a pressure relief device attached with a pressure relief plate, a cylindrical protective cover extending from the outer peripheral portion of the pressure relief plate of the pressure relief device so as to surround the pressure relief plate, and the protection And a protective net provided at a tip opening portion of the cover so as to prevent fragments of the pressure-proof plate and components inside the terminal box from being scattered far away.
[0019]
The invention according to claim 3 is characterized in that, in the invention according to

claim

1 or 2 , varnish or resin is applied to at least one surface of the pressure relief plate of the pressure relief device.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a view showing a first embodiment of the present invention. A container-like terminal box 2 comprising a main body portion 2a and a cover portion 2b is attached to a side wall of a rotating electrical machine main body 1, and the terminal box The lead wire 4 drawn from the lead wire lead-in portion 3 in 2 is connected to the power cable 6 via the terminal 5, and the connection portion is covered with the terminal box 2.
[0021]
The pressure relief device 9 is not at an arbitrary position of the terminal box as in the conventional example of FIG. 8, but is opposed to the side surface side where the lead wire lead-out portion 1a of the rotating electrical machine 1 is provided and is separated from the side surface of the rotating electrical machine. Attached to the side wall. Further, the pressure relief plate 10 is enlarged so that a large opening area is formed at the time of rupture.
[0022]
When an interphase short-circuit occurs in the terminal 5 or other conductive portion (for example, U-phase and V-phase short-circuit), the internal pressure of the terminal box 2 rapidly increases by arc discharge as described in the conventional example. At this time, due to the difference between the above-described conventional example and the present invention, the pressure relief plate 10 is ruptured in a shorter time from the occurrence of a short-circuit between the phases with a lower internal pressure rise. Thus, although the terminal box 2 is slightly deformed in some cases, the holding plate 11 and the mounting bolt 12 of the terminal box 2 are scattered, or the terminal box 2 is greatly deformed to widen the clearance of the terminal box cover mounting portion, and the arc is generated therefrom. Is not greatly ejected or the terminal box 2 is not damaged, that is, the pressure release device functions normally, and the internal pressure of the terminal box 2 is released. In addition, since fragments such as a pressure relief plate are scattered between the rotating electrical machine main body 1 and the terminal box 2 that cannot be entered by humans, it is possible to prevent the occurrence of personal injury.
[0023]
In order to confirm the effects of the present invention, the following tests were conducted.
[0024]
The terminal box 2 used as a test sample has a shape similar to that shown in FIG. 1 and the dimensions thereof are as shown in Table 1. Conventionally, the strength of each part such as the material and thickness of the wall surface and the connecting part with the lid is generally used. It is equivalent to the terminal box that has been manufactured. For comparison, specimens were also used in which the dimensions and thickness of each part and the strength of the bolts at the joints were slightly changed so as not to differ greatly from the conventional products. Furthermore, several specimens are prepared in which the opening area of the pressure plate 10 is changed to a larger or smaller size or the mounting position of the pressure plate 10 is changed, and it is assumed when an accident occurs under general installation conditions and usage conditions. An actual inter-phase short-circuit test was performed under short-circuit conditions.
[0025]
[Table 1]

[0026]
The main results of the experiment are shown in FIG. 2 which summarizes the relationship between the volume V of the terminal box, the opening area A of the pressure relief plate, and whether or not the pressure relief device functions normally. As can be seen from FIG. 2, the condition for the normal functioning of the pressure relief device can be expressed as “A / V ≧ C (C: constant)”. As a specific example, in the terminal box having the dimensions shown in Table 1, in this test, when the unit of area A and volume V is m ² and m ³ respectively and A / V is smaller than 0.2, the pressure relief device is normal. Didn't work. From the above, it has been shown that the larger the opening area of the pressure relief plate, the larger the value of A / V and the higher the safety.
[0027]
In addition, as a result of performing a test under the same conditions while changing only the mounting position of the pressure relief device, it faces the side surface where the lead wire lead portion 1a of the rotating electrical machine 1 is provided and is separated from the side surface of the rotating electrical machine. Compared with the case where the pressure relief device 9 is attached to the side wall, when the pressure relief device 9 is attached to the other surface, the fragments of the pressure relief plate and the constituent materials of the terminal box are scattered further away. From the above, the safety can be further improved by attaching the pressure relief device to the side wall of the terminal box that faces the side surface of the rotating electrical machine 1 where the lead wire lead portion 1a is provided and is spaced from the side surface of the rotating electrical machine. It was shown to increase.
[0028]
Therefore, as is clear from the above results, according to the present embodiment, in the above situation, the pressure relief plate bursts instantly and in a short time before the terminal box body is damaged by the internal pressure, and the expansion gas is Since it can be discharged quickly and harm to the surroundings can be reduced, safety can be improved as compared with the conventional terminal box.
[0029]
In the embodiment of the present invention, the structure of the portion other than the pressure relief device may be substantially the same as that of the conventional terminal box, so the rotating electrical machine main body and the terminal box mounting portion have the same shape as the existing terminal box. Since it is good, the improvement which attaches the terminal box of this invention with respect to the existing rotary electric machine is easy.
[0030]
In the above description, it is assumed that the terminal box of the present invention is newly manufactured. However, since the structure of the part other than the pressure relief device may be substantially the same as the conventional terminal box, the existing terminal box is used. On the other hand, the object of the present invention can be achieved by modifying the pressure relief device according to the embodiment of the present invention.
[0031]
Further, the pressure relief plate 10 may be a film shape instead of a plate shape. Further, between the terminal box 1 and the pressure-reducing plate 10 and between the pressure-reducing plate 10 and the presser plate 11, a packing may be inserted or a sealing material may be applied for waterproofing and dust-proofing.
[0032]
FIGS. 3 and 4 are views showing a second embodiment of the present invention, in which a varnish or a resin 13 is applied to at least one surface of the pressure relief plate 10 which is a component of the pressure relief device and dried. It has been.
[0033]
Therefore, when the internal pressure of the terminal box increases due to a short circuit accident between the phases, if the pressure-reducing plate 10 is deformed due to the pressure, a fine mesh is formed on one surface of the varnish or resin 13 that has been applied, dried and hardened. From this point, the pressure relief plate itself is easily burst into pieces at once. Therefore, safety can be further improved.
[0034]
In addition, when apply | coating a varnish to a pressure-reduction board, as shown in FIG. 4, the same effect can be acquired even if it applies only to the center part, without applying to the whole surface of the pressure-reduction board 10. FIG.
[0035]
Further, FIG. 5 is a diagram showing a third embodiment of the present invention, and a cylindrical protective cover 14 is formed so as to surround the pressure relief plate 10 from the outer peripheral portion of the pressure relief plate 10 toward the outside of the terminal box 2. A protective net 15 is provided at the opening at the tip of the protective cover 14. The terminal box 2, the protective cover 14, and the protective net 15 all have a structural strength that can withstand a load such as a fallen object from the outside. The terminal box 2 and the protective cover 14 also have thermal strength that can withstand high temperatures. In FIG. 5, the protective cover 14 has a structure that also serves as a pressing plate for the pressure-reducing plate 10, but these may be formed of separate components.
[0036]
Therefore, when the internal pressure of the terminal box 2 rises due to a phase short circuit accident, the protective cover 14 and the protective net 15 can suppress the fragments of the pressure relief plate 10 and the scattering of the components inside the terminal box.
[0037]
It should be noted that the size of the mesh of the protective mesh is set to be slightly smaller than the shattered pressure relief plate pieces, thereby further preventing the pieces from being scattered. However, in order to quickly discharge the gas expanded inside the terminal box, the mesh should not be made too small.
[0038]
Further, in consideration of the direction of the protective cover 14 and directing a short-circuit arc or the like in a direction where no one is present, it is possible to further suppress the harm to the human body in the event of an accident.
[0039]
Therefore, as is clear from the above results, according to the present embodiment, even when the specification that “a fallen object hits from outside does not break” is required for the terminal box 2 of the rotating electrical machine. The specifications can be satisfied by the protective cover and the protective net, and the safety as the pressure relief device can be further enhanced. The second and third embodiments may be used in combination with the first embodiment. In this case, safety can be further improved.
[0040]
【The invention's effect】
As described above, the present invention not only prevents damage and scattering of the terminal box components due to the increase in internal pressure due to the action of the pressure relief device when a short circuit arc between phases occurs in the terminal box of the rotating electrical machine, At the time of pressure release, it is possible to reduce the harm to surrounding equipment or the human body due to the discharge of the arc and the scattering of the components of the terminal box, and the safety can be improved as compared with the conventional terminal box.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a terminal box showing a first embodiment of the present invention.
FIG. 2 is a characteristic diagram showing a result of a short-circuit test for the first embodiment of the present invention.
FIG. 3 is a diagram showing an example of a terminal box pressure relief device showing a second embodiment of the present invention;
FIG. 4 is a view showing another example of a terminal box pressure relief device showing a second embodiment of the present invention;
FIG. 5 is a view showing an example of a terminal box pressure release device showing a third embodiment of the present invention;
FIG. 6 is a perspective view showing a terminal box mounting state of a general rotating electrical machine.
FIG. 7 is a configuration diagram of a terminal box of a conventional rotating electrical machine.
FIG. 8 is a configuration diagram of a terminal box of a rotating electric machine with a conventional pressure relief device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating electrical machine main body 2 Terminal box 3 Lead wire lead-in part 4 Lead wire 5 Terminal 6 Power supply cable 7 Cable fixing clamp 8 Mounting bolt 10 Pressure-reducing plate 11 Pressure-reducing plate holding plate 12 Pressure-reducing plate fixing bolt 13 Varnish or resin 14 Pressure-reducing plate protection cover 15 Protection plate protection net

Claims

A lead wire and terminal box mounted on the rotary electric machine so as to cover the connection terminals for connecting the lead wire to the power cable of the rotary electric machine,
Of the terminal box, on the side wall facing the side surface where the lead wire lead-out portion of the rotating electrical machine is provided and spaced from the side surface,
A pressure relief device is provided to which a pressure relief plate having an area where the ratio A / V of the area A of the pressure relief plate and the volume V of the terminal box is 0.2 or more is attached. Terminal box for rotating electrical machines.

A terminal box attached to the rotating electrical machine so as to cover a lead wire of the rotating electrical machine and a connection terminal for connecting the lead wire to the power cable,
On the side wall of the terminal box, a pressure relief device attached with a pressure relief plate, a cylindrical protective cover extending from the outer peripheral portion of the pressure relief plate of the pressure relief device so as to surround the pressure relief plate, and the protection A terminal box for a rotating electrical machine, provided with a protective net provided at a tip opening portion of the cover so as to prevent fragments of the pressure-proof plate and components inside the terminal box from being scattered far away .

The terminal box for a rotating electrical machine according to claim 1 or 2, wherein varnish, resin, or the like is applied to at least one surface of the pressure relief plate of the pressure relief device.