JP4015412B2

JP4015412B2 - Sealed electric compressor and protection device for refrigeration equipment

Info

Publication number: JP4015412B2
Application number: JP2001381128A
Authority: JP
Inventors: 俊雄島田; 渉菅原
Original assignee: Hitachi Appliances Inc
Current assignee: Hitachi Appliances Inc
Priority date: 2001-12-14
Filing date: 2001-12-14
Publication date: 2007-11-28
Anticipated expiration: 2021-12-14
Also published as: JP2003189684A

Description

【０００１】
【発明の属する技術分野】
本発明は、密閉形電動圧縮機及び冷凍装置の保護装置に係り、特に三相誘導電動機を用いた密閉形電動圧縮機及び空気調和機や電気冷蔵庫等の冷凍装置の保護装置に好適なものである。
【０００２】
【従来の技術】
従来の冷凍装置の保護装置としては、図１８に示すように、三相誘導電動機３を用いた密閉形電動圧縮機６と、三相誘導電動機３の三相電源の全ラインＲ、Ｓ、Ｔに接点１Ｒ、１Ｓ、１Ｔを接続した電磁接触装置１と、この接点１Ｒ、１Ｔより電源側の二つの電源ラインＲ、Ｔに接続したバイメタル式過負荷保護装置２Ｒ、２Ｔと、抵抗器５Ｒ、コンデンサ５Ｃ及び継電器コイル５Ｌを各電源ラインＲ、Ｓ、Ｔ間に接続した逆転防止装置５と、単相誘導電動機１２を用いた送風装置とを備えるものがある。
【０００３】
そして、電磁接触装置１の操作コイル１Ｌは過負荷保護装置２Ｒ、２Ｔを接続した電源ラインＲ、Ｔ間に継電器コイル５Ｙの接点５Ａを直列に介して接続し、操作コイル１Ｌの一側は一方の過負荷保護装置２Ｒの中性点端子２Ｎに接続すると共に、操作コイル１Ｌの他側は他方の過負荷保護装置２Ｔの中性点端子２Ｎに接続している。
【０００４】
抵抗器５Ｒは一方の過負荷保護装置２Ｒの電源側に接続している。継電器コイル５Ｌは他方の過負荷保護装置２Ｔの電源側に接続している。コンデンサ５Ｃは残りの電源ラインＳに接続している。
【０００５】
過負荷保護装置２Ｒ、２Ｔはヒータ２Ｈとバイメタル２Ｂを直列接続して形成し、過負荷保護装置２Ｒ、２Ｔのヒータ側を電動機側に接続すると共にバイメタル側を電源側に接続している。また、単相誘導電動機１２は過負荷保護装置２Ｒ、２Ｔの電源側に接続している。
【０００６】
この従来技術に関連するものとして、特開平７−２６２８９５号公報が挙げられる。
【０００７】
【発明が解決しようとする課題】
しかしながら、従来の保護装置では、過負荷保護装置２Ｒ、２Ｔが接続されていない電源Ｓが途中欠相した場合には、過負荷保護装置２Ｒ又は２Ｔの開閉により三相誘導電動機３のＲ−Ｔ相単相通電運転とその停止が繰り返しされ、過負荷保護装置２Ｒ、２Ｔの寿命が短くなってしまうという課題があった。
【０００８】
この点を更に具体的に説明する。三相誘導電動機３が通常運転中にＳ相の電源側が途中欠相しても、Ｒ相−抵抗器５Ｒ−継電器コイル５Ｌ−Ｔ相の回路に通電されて継電器コイル５Ｌによる接点５Ａの閉路動作が継続されることにより、操作コイル１Ｌによる接点１Ｒ、１Ｓ、１Ｔの閉路動作が継続され、三相誘導電動機３はＲ−Ｔ単相通電で回転運動が継続される。この状態で、例えば過負荷保護装置２Ｒが開路動作すると、三相誘導電動機３の巻線３Ｒの電路が遮断されて三相誘導電動機３が停止するが、その後、過負荷保護装置２Ｒが閉路動作すると、操作コイル１Ｌに通電されて接点１Ｒ、１Ｓ、１Ｔが閉路することにより、三相誘導電動機３がＲ−Ｔ単相通電で運転が再開される。以下、過負荷保護装置２Ｒ、２Ｔの開閉により、三相誘導電動機３のＲ−Ｔ単相運転及び停止が繰り返される。
【０００９】
また、従来の保護装置では、単相誘導電動機１２は過負荷保護装置２Ｒ、２Ｔの電源側に接続しているため、Ｓ相が途中欠相し且つ過負荷保護装置２Ｒ、２Ｔが開路しても単相誘導電動機１２の運転が継続され、その保護が行なわれないという課題があった。しかも、二つの過負荷保護装置２Ｒ、２Ｔに流れる電流は単相誘導電動機３に流れる電流が加算されないため、二つの過負荷保護装置２Ｒ、２Ｔを異なる所に配置した場合には、設置場所に対応した仕様の異なる過負荷保護装置を準備しなければならないという課題があった。
【００１０】
更に、従来の保護装置は、過負荷保護装置２Ｒ、２Ｔのヒータ側を電動機側に接続すると共にバイメタル側を電源側に接続しているため、過負荷保護装置２Ｒ、２Ｔのヒータ２Ｂが途中切断された場合には、Ｒ相、Ｔ相の途中欠相の場合よりも保護特性が低下するという課題があった。
【００１１】
本発明の目的は、いずれの相に欠相が生じても、三相誘導電動機の単相拘束通電を１回限りとすることができると共に、過負荷保護装置の寿命を損なうこともないので、高信頼性、高安全性の保護装置を提供することにある。
【００１２】
なお、本発明はかかる目的に限定されるものではなく、前記以外の目的と有利点は以下の記述から明らかにされる。
【００１３】
【課題を解決するための手段】
前記目的を達成するために、本発明は、三相誘導電動機を用いた密閉形電動圧縮機と、前記三相誘導電動機の三相電源の全ラインに接点を接続した電磁接触装置と、この接点より電源側の二つの電源ラインに接続したバイメタル式過負荷保護装置と、抵抗器、コンデンサ及び継電器コイルを前記各電源ライン間に接続した逆転防止装置とを備え、前記過負荷保護装置を接続した電源ライン間に電磁接触装置の操作コイルを前記継電器コイルの接点を介して接続すると共に、前記過負荷保護装置の一方を接続した電源ラインに前記抵抗器を接続し、前記過負荷保護装置の他方を接続した電源ラインに前記継電器コイルを接続し、残りの前記電源ラインに前記コンデンサを接続した密閉形電動圧縮機の保護装置において、前記過負荷保護装置のうちの一方の過負荷保護装置の中性点端子に前記操作コイルの一側を接続すると共に、前記過負荷保護装置のうちの他方の過負荷保護装置と前記電磁接触装置の接点との間に前記操作コイルの他側を接続し、前記一方の過負荷保護装置と前記電磁接触装置の接点との間に前記抵抗器を接続すると共に、前記他方の過負荷保護装置の中性点端子に前記継電器コイルを接続したことにある。
【００１４】
なお、前記目的以外の目的を達成するための本発明の保護装置は以下の記述から明らかにされる。
【００１５】
【発明の実施の形態】
以下、本発明の複数の実施例を図を用いて説明する。なお、各実施例の図における同一符号は同一物又は相当物を示す。
【００１６】
まず、本発明の第1実施例を図１から図９を用いて説明する。
【００１７】
本実施例の冷凍装置の全体構成、機能及び動作を図２及び図３を参照しながら説明する。図２は本発明の第１実施例を適用した冷凍装置の構成図、図３は図２の冷凍装置に用いる密閉形電動圧縮機における過負荷保護装置の据付例を示す図である。
【００１８】
本実施例の冷凍装置は、冷凍サイクル及び送風装置１１などで構成され、空気調和機や冷蔵庫などに適用される。
【００１９】
冷凍サイクルは、密閉形電動圧縮機６、凝縮器８、膨張弁１０及び蒸発器９を冷媒配管で順次接続して形成されている。また、送風装置１１は、単相誘導電動機１２、この単相誘導電動機１２により回転されるファン１３、ファン１４を備えている。この冷凍サイクル中を冷媒が循環され、この冷媒が送風装置１１により送られる空気と凝縮器８及び蒸発器９で熱交換することにより、冷却機能が発揮される。即ち、冷凍サイクル中で、冷媒は、密閉形電動圧縮機６で圧縮されて高温高圧になり、凝縮器８でファン１３により通風される空気と熱交換して凝縮し、膨張弁１０で減圧されて低圧となり、蒸発器９でファン１４により通風される空気と熱交換して蒸発し、密閉形電動圧縮機６に戻ることにより、冷却機能が発揮される。膨張弁１０はキャピラリチューブや膨張弁等で形成される。
【００２０】
そして、電磁弁１５は密閉形電動圧縮機６と並列に接続され、冷凍サイクルの運転時に閉路し、停止時に開路して密閉形電動圧縮機６の両側の圧力バランスを早期に達成するように制御される。なお、本発明は、冷凍サイクル冷媒の流れを制御する他の部分に用いられる電磁弁にも適用可能である。
【００２１】
また、密閉形電動圧縮機６の外殻には、図３（ａ）に示すように一対の過負荷保護装置２Ｒ、２Ｔが設置されている。この過負荷保護装置２Ｒ、２Ｔは、密閉形電動圧縮機６の外殻の温度上昇と運転電流の増加の両者を感知して動作する。
【００２２】
なお、密閉形電動圧縮機６に過負荷保護装置２Ｒ、２Ｔの両方を収納するスペースがない場合には、図３（ｂ）に示すように、一方の過負荷保護装置２Ｔのみが密閉形電動圧縮機６に取り付け、他方の過負荷保護装置２Ｒが密閉形電動圧縮機６から離れた所、例えば電気品室等に取り付けるようにしてもよい。この場合では、過負荷保護装置２Ｔは温度と電流の両者を感知し、過負荷保護装置２Ｒは電流を感知して開路動作をすることになる。
【００２３】
上述した密閉形電動圧縮機６の保護装置の構成を図１を参照しながら説明する。
【００２４】
三相誘導電動機３は、密閉形電動圧縮機６の外殻内に収納され、圧縮機構部を動作させるためのものである。三相誘導電動機３は、三相電源の各相のラインＲ、Ｓ、Ｔにスター結線された電動機巻線３Ｒ、３Ｓ、３Ｔを有している。
【００２５】
全電源ラインＲ、Ｓ、Ｔの密閉形電動圧縮機６外部に位置する部分には、電磁接触装置１の接点１Ｒ、１Ｓ、１Ｔが接続されている。電磁接触装置１は操作コイル１Ｌと接点１Ｒ、１Ｓ、１Ｔとから構成され、操作コイル１Ｌに所定電圧が通電された場合に接点１Ｒ、１Ｓ、１Ｔを閉路する。
【００２６】
二つの電源ライン（図示例では電源ラインＲ、Ｔ）における接点１Ｒ、１Ｔより電源側には、過負荷保護装置２Ｒ、２Ｔが接続されている。この過負荷保護装置２Ｒ、２Ｔは、バイメタル２Ｂ、可動接点２Ｃ及び中性点端子２Ｎを有している。バイメタル２Ｂは流れる電流による自己発熱及び周囲温度を感知して可動し、可動接点２Ｃが電源ラインＲ、Ｔを開閉する
操作コイル１Ｌは、過負荷保護装置２Ｒの中性点端子２Ｎと、過負荷保護装置２Ｔの電動機側で且つ接点１Ｔの電源側（過負荷保護装置２Ｔと接点１Ｔとの間）の電源ラインＲとの間に、開閉装置４及び接点５Ａを直列に介して接続されている。開閉装置４は三相誘導電動機３を始動するためのものであり、手動スイッチや温度調節器等で構成され、過負荷保護装置２Ｒの中性点端子２Ｎと操作コイル１Ｌとの間に接続されている。接点５Ａは三相誘導電動機３を保護するためのものであり、電源ラインＴと操作コイル１Ｌとの間に接続されている。また、接点５Ａは継電器コイル５Ｌと共に電磁継電器５Ｙを構成し、継電器コイル５Ｌに所定電圧が通電された場合に閉路される。
【００２７】
逆転防止装置５は、電磁継電器５Ｙ、コンデンサ５Ｃ及び抵抗器５Ｒから構成されている。継電器コイル５Ｌは、一側が過負荷保護装置２Ｔの中性点端子２Ｎに接続され、他側がコンデンサ５Ｃを直列に介して電源ラインＳに接続されると共に、抵抗器５Ｒを直列に介して過負荷保護装置２Ｒの電動機側で且つ接点１Ｒの電源側（過負荷保護装置２Ｒと接点１Ｒの間）の電源ラインＲに接続されている。
【００２８】
次に密閉形電動圧縮機６の逆転防止装置５の動作について説明する。
【００２９】
密閉形電動圧縮機６には種々の形態があり、例えばレシプロ方式、ロータリ方式、スクロール方式、スクリュー方式等がある。これを駆動する三相誘導電動機３を位相制御することなく電源に接続すると、接続された時の位相が正相か逆相かで左回転になったり右回転になったりする。
【００３０】
回転方向に関係なく冷媒の圧縮が可能な方式はレシプロ方式のみで、他の方式は全て圧縮不能になる。又、レシプロ方式の場合でも、圧縮機の給油構造が左右回転に耐えるものでないと、三相誘導電動機３が使用出来ないという問題がある。そこで、三相誘導電動機３の回転方向を一定方向に保持するため逆転防止装置５が用いられている。この逆転防止装置５は正相時に接点５Ａが閉じ、逆相時にその接点５Ａが閉じないように構成し、正相時になった時に三相誘導電動機３が正回転で始動されるようにしている。
【００３１】
ここで、逆転防止装置５の動作原理について図４及び図５を参照しながら説明する。
【００３２】
三相電源は各相間の位相が互いに２π／３ラジアンずつ異なる対称交流である。このずれを電気の三要素である抵抗器５Ｒ、コンデンサ５Ｃ、継電器コイル５Ｌから構成される位相回路の性質（即ち、抵抗器５Ｒは電圧に対して電流の遅れ進みに無関係、コンデンサ５Ｃは電圧に対して電流が進む、継電器コイル５Ｌは電圧に対して電流が遅れる性質）を利用し、夫々の抵抗器５Ｒ、コンデンサ５Ｃ、継電器コイル５Ｌを上述したように各相間に接続し、継電器コイル５Ｌに流れる電流の大小で逆転防止装置５の接点５Ａを動作せしめる構成になっている。
【００３３】
正相時の電圧と継電器コイル５Ｌに流れる電流とをベクトルで表すと図４（ａ）〜（ｄ）のようになる。図４（ａ）は正相時の電圧位相を示し、ＶＲは抵抗器５Ｒ、ＶＣはコンデンサ５Ｃ、ＶＴは継電器コイル５Ｌの電圧位相である。図４（ｂ）は正相時の電流位相を示し、ＩＲは抵抗器５Ｒ、ＩＣはコンデンサ５Ｃ、ＩＬは継電器コイル５Ｌの電流位相である。図４（ｃ）はＩＲとＩＣの合成電流ＩＲＣ、ＩＲとＩＬの合成電流ＩＲＬを示す。図４（ｄ）はＩＲＣとＩＲＬの合成電流ＩＲＣＬを示す。
【００３４】
この図４から明らかなように、正相時には継電器コイル５Ｌには大きな電流が流れるため、電磁継電器５Ｙが付勢されて接点５Ａが閉じる。
【００３５】
逆相時の電圧と継電器コイル５Ｌに流れる電流とをベクトルで表すと図５（ａ）〜（ｃ）のようになる。図５（ａ）は逆相時の電圧位相を示し、ＶＲは抵抗器５Ｒ、ＶＣはコンデンサ５Ｃ、ＶＴは継電器コイル５Ｌを接続した電圧位相である。図５（ｂ）は逆相時の電流位相を示し、ＩＲは抵抗器５Ｒ、ＩＣはコンデンサ５Ｃ、ＩＬは継電器コイル５Ｌの電流位相である。図５（ｃ）はＩＣとＩＬの合成電流ＩＬＣを示す。
【００３６】
この図５から明らかなように、逆相時には継電器コイル５Ｌに流れる電流はＩＬＣとＩＲが互いに逆方向の関係になることから互いにキャンセルされ、ごくわずかの励磁電流のみが流れるため、電磁継電器５Ｙが動作せず、結果として逆転防止装置５の接点５Ａは閉じることが出来ず開いたままになる。そして、電圧位相が正相に変わると、上述したように正回転で運転が開始される。
【００３７】
次に密閉形電動圧縮機６の保護装置の基本的な動作を図１を参照しながら説明する。
【００３８】
開閉装置４が閉路されると、電磁接触機１の操作コイル１Ｌに通電されて電磁接触装置１が付勢され、接点１Ｒ、１Ｓ、１Ｔが閉じて三相誘導電動機３が通電状態になり、三相誘導電動機３の運転が開始される。これと逆に開閉装置４が開路されると、電磁接触装置１の操作コイル１Ｌの通電が断たれ、接点１Ｒ、１Ｓ、１Ｔが開いて三相誘導電動機３の通電が断たれ、三相誘導電動機３の運転が停止される。
【００３９】
ここで、開閉装置４が閉路した時、何等かの理由により三相誘導電動機３が始動出来ずに電源ラインＲ、Ｓ、Ｔに大きな拘束電流が流れ続けると、一対の過負荷保護装置２Ｒ、２Ｔのバイメタル２Ｂが発熱される。この発熱によって設定されたバイメタル２Ｂの反転動作温度に達すると、動作温度の低い方の過負荷保護装置２Ｒ又は２Ｔの可動接点２Ｃが開路動作する。
【００４０】
この開路動作により三相誘導電動機３の一つの電源ラインＲ又はＴが遮断されると共に、電磁接触装置１の操作コイル１Ｌの通電も遮断される。この操作コイル１Ｌの遮断から若干遅れて接点１Ｒ、１Ｓ、１Ｔが開路動作し（この遅れ動作現象を電磁接触装置１の復帰時間と言う）、三相誘導電動機３の残りの電源ラインが遮断される。これによって、三相誘導電動機３は完全に電源ラインＲ、Ｓ、Ｔから切り離される。
【００４１】
動作した過負荷保護装置２Ｒ又は２Ｔのバイメタル２Ｂが周囲の空気で冷却され、設定されたバイメタル２Ｂの反転復帰温度に達すると、再び可動接点２Ｃが閉路動作して、電磁接触装置１の操作コイル１Ｌに通電される。この操作コイル１Ｌへの通電より若干遅れて接点１Ｒ、１Ｓ、１Ｔが閉路動作し、三相誘導電動機３が再び通電される。
【００４２】
この時、三相誘導電動機３の拘束原因が排除されていれば三相誘導電動機３は正常に始動し運転する。しかしながら、拘束原因が排除されることなく継続している場合には、前述同様の拘束電流により過負荷保護装置２Ｒ又は２Ｔのいずれか一方が開路動作及び閉路動作を繰り返す。この繰り返し動作による拘束電流の通電では、電動機巻線３Ｒ、３Ｓ、３Ｔが温度上昇で過熱焼損しないように設定されている。
【００４３】
次に、三相誘導電動機３が三相電源で正常に運転中にそのうち一相が欠相した場合の保護動作について図６から図９を参照しながら説明する。三相電源ラインＲ、Ｓ、Ｔは、配電盤内のヒューズ動作やコード接続取付部のネジの弛み等で一つの電源ラインが欠相することがある。
【００４４】
Ｒ相が途中欠相した場合について図６及び図７を参照しながら説明する。
【００４５】
Ｒ相が図６の×印で示すように途中欠相しても、Ｓ相−コンデンサ５Ｃ−継電器コイル５Ｌ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されて継電器コイル５Ｌによる接点５Ａの閉路動作が継続される。これによって、継電器コイル５Ｌには、図７（ａ）に示す２π／３ラジアン位相がずれた電圧ＶＴ、ＶＳが印加され、図７（ｂ）に示す合成電流ＩＬＣが流れる。電源電圧が定格に近い範囲では、この合成電流ＩＬＣで電磁継電器５Ｙの接点５Ａの閉路が保持される。従って、Ｓ相−接点１Ｓ−電動機巻線３Ｓ−電動機巻線３Ｒ−接点１Ｒ−過負荷保護装置２Ｒ−開閉装置４−操作コイル１Ｌ−接点５Ａ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されて操作コイル１Ｌによる接点１Ｒ、１Ｓ、１Ｔの閉路動作が継続される。その結果、Ｓ相−接点１Ｓ−電動機巻線３Ｓ−電動機巻線３Ｔ−接点１Ｔ−過負荷保護装置２Ｔ−Ｔ相のように通電され、三相誘導電動機３はＳ−Ｔ単相通電で回転を継続する。
【００４６】
このように、三相誘導電動機３が途中欠相状態で単相通電されて運転が継続されていると、電密閉形電動圧縮機６は正常な三相運転と比べ過負荷状態になり、密閉形電動圧縮機６の外殻に取り付けられている一対の過負荷保護装置２Ｒ及び２Ｔ（図３（ａ）参照）は外殻の温度上昇と運転電流の増加の両者を感知して動作温度に達すると開路動作する。単相運転では、通常、三相正常運転時の電流の約１５％増しの電流がこの二相間に流れるからである。
【００４７】
上述した三相誘導電動機３のＳ−Ｔ単相通電の状態で、例えば過負荷保護装置２Ｔが図６の破線の如く開路動作すると、三相誘導電動機３の巻線３Ｔの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌと電磁接触装置１の操作コイル１Ｌの通電が遮断され、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。
【００４８】
その後、過負荷保護装置２Ｔが閉路動作すると、Ｓ相−コンデンサ５Ｃ−継電器コイル５Ｌ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されて接点５Ａが閉路され、Ｓ相−コンデンサ５Ｃ−抵抗器５Ｒ−過負荷保護装置２Ｒ−開閉装置４−操作コイル１Ｌ−接点５Ａ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されるが、この回路の夫々の分担電圧は抵抗器５Ｒがその大半を受け持つように設定してあるため、電磁接触装置１の操作コイル１Ｌは動作するに必要な電圧が得られず、電磁接触装置１の接点１Ｒ、１Ｓ、１Ｔは開路状態が保持される。換言すれば、コンデンサ５Ｃ−抵抗器５Ｒ−操作コイル１Ｌの直列回路電流が流れるが、その電流が極めて小さく、電磁接触装置１の接点１Ｒ、１Ｓ、１Ｔの閉路動作に必要な操作コイル１Ｌのアンペアターンが得られない。従って、三相誘導電動機３の停止が維持される。
【００４９】
一方、上述した三相誘導電動機３がＳ−Ｔ単相通電されている状態で、過負荷保護装置２Ｒが開路動作すると、三相誘導電動機３の巻線３Ｒの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌと電磁接触装置１の操作コイル１Ｌの通電が遮断され、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。
【００５０】
そして、その後に過負荷保護装置２Ｒが閉路動作した場合は、上述した過負荷保護装置２Ｔが閉路動作した場合と同様に動作し、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔの開路状態が保持される。従って、三相誘導電動機３の停止状態が維持される。
【００５１】
このように、Ｒ相が途中欠相した場合には、三相誘導電動機３はまずＳ−Ｔ単相通電がなされて回転が継続され、過負荷保護装置２Ｔ又は過負荷保護装置２Ｒが一度開路動作することにより三相誘導電動機３への通電が断たれて回転が停止され、その後過負荷保護装置２Ｔ又は過負荷保護装置２Ｒが開閉動作しても三相誘導電動機３の停止状態が維持される。
【００５２】
Ｓ相が途中欠相した場合について図８を参照しながら説明する。
【００５３】
Ｓ相が図８の×印で示すように途中欠相しても、Ｒ相−過負荷保護装置２Ｒ−抵抗器５Ｒ−継電器コイル５Ｌ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されて継電器コイル５Ｌによる接点５Ａの閉路動作が継続される。この回路は分担電圧の大半を抵抗器５Ｒが受け持つことにより継電器コイル５Ｌの分担電圧が小さく流れる電流が小さくなるが、接点５Ａの閉路状態を継続するだけであれば継電器コイル５Ｌの分担電圧が小さくても接点５Ａの閉路状態を継続することができる。これによって、Ｒ相−過負荷保護装置２Ｒ−開閉装置４−操作コイル１Ｌ−接点５Ａ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されて操作コイル１Ｌによる接点１Ｒ、１Ｓ、１Ｔの閉路動作が継続される。その結果、Ｒ相−過負荷保護装置２Ｒ−接点１Ｒ−電動機巻線３Ｒ−電動機巻線３Ｔ−接点１Ｔ−過負荷保護装置２Ｔ−Ｔ相の回路に通電される。三相誘導電動機３はＲ−Ｔ単相通電となるが、電動機巻線３Ｓと３Ｒに流れる電流で回転磁界が形成されているため、Ｒ−Ｔ単相通電であっても回転運動が継続される。
【００５４】
この三相誘導電動機３のＲ−Ｔ単相通電の状態で、例えば過負荷保護装置２Ｒが図８の破線の如く開路動作すると、三相誘導電動機３の巻線３Ｒの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌと電磁接触装置１の操作コイル１Ｌの通電が遮断され、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。
【００５５】
その後、過負荷保護装置２Ｒが閉路動作すると、Ｒ相−過負荷保護装置２Ｒ−抵抗器５Ｒ−継電器コイル５Ｌ−過負荷保護装置２Ｔ−Ｔ相の回路に通電される。しかし、この回路の夫々の分担電圧は上述したように抵抗器５Ｒがその大半を受け持つように設定してあるため、継電器コイル５Ｌは接点５Ａを閉路動作させるに必要な電圧が得られず、接点５Ａは閉路されることなく開路したままとなる。換言すれば、接点５Ａを閉路させる継電器コイル５Ｌの動作電圧は閉路した接点５Ａの保持電圧よりはるかに大きいために、過負荷保護装置２Ｒの開路動作により継電器コイル５Ｌの通電が断たれて接点５Ａが開路すると、抵抗器５Ｒを介した継電器コイル５Ｌの回路では接点５Ａを閉路させる動作電圧が得られない。この接点５Ａの回路状態これによって、操作コイル１Ｌに通電されない状態が維持され、接点１Ｒ、１Ｓ、１Ｔの開路状態が維持される。従って、三相誘導電動機３の停止状態が維持される。
【００５６】
一方、三相誘導電動機３がＲ−Ｔ単相通電されている状態で、過負荷保護装置２Ｔが開路動作すると、三相誘導電動機３の巻線３Ｔの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌと電磁接触装置１の操作コイル１Ｌの通電が遮断され、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。
【００５７】
そして、その後に過負荷保護装置２Ｔが閉路動作した場合は、上述した過負荷保護装置２Ｒが閉路動作した場合と同様に動作し、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔの開路状態が維持される。従って、三相誘導電動機３の停止状態が維持される。
【００５８】
このように、Ｓ相が途中欠相した場合には、三相誘導電動機３はまずＲ−Ｔ単相通電がなされて回転が継続され、過負荷保護装置２Ｒ又は過負荷保護装置２Ｔが一度開路動作すると、三相誘導電動機３への通電が断たれて回転が停止され、その後過負荷保護装置２Ｒ又は過負荷保護装置２Ｔが開閉動作しても三相誘導電動機３の停止状態が維持される。
【００５９】
Ｔ相が途中欠相した場合について図９を参照しながら説明する。
【００６０】
Ｔ相が図９の×印で示すように途中欠相しても、Ｓ相−コンデンサ５Ｃ−継電器コイル５Ｌ−過負荷保護装置２Ｔ−接点１Ｔ−電動機巻線３Ｔ−電動機巻線３Ｒ−接点１Ｒ−過負荷保護装置２Ｒ−Ｒ相の回路に通電されて継電器コイル５Ｌによる接点５Ａの閉路動作が継続される。これによって、Ｒ相−過負荷保護装置２Ｒ−開閉装置４−操作コイル１Ｌ−接点５Ａ−過負荷保護装置２Ｔ−電動機巻線３Ｔ−電動機巻線３Ｓ−接点１Ｓ−Ｓ相の自己保持回路に通電されて操作コイル１Ｌによる接点１Ｒ、１Ｓ、１Ｔの閉路状態が継続される。その結果、Ｒ相−過負荷保護装置２Ｒ−接点１Ｒ−電動機巻線３Ｒ−電動機巻線３Ｓ−接点１Ｓ−Ｓ相の回路に通電され、三相誘導電動機３はＲ−Ｓ単相通電で回転を継続する。
【００６１】
この状態で、例えば過負荷保護装置２Ｒが図９の破線の如く開路動作すると、三相誘導電動機３の巻線３Ｒの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌと電磁接触装置１の操作コイル１Ｌの通電が遮断され、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。
【００６２】
その後、過負荷保護装置２Ｒが閉路動作すると、Ｒ相−過負荷保護装置２Ｒ−抵抗器５Ｒ−継電器コイル５Ｌ−過負荷保護装置２Ｔ−接点１Ｔ−電動機巻線３Ｔ−電動機巻線３Ｓ−接点１Ｓ−Ｓ相の回路に通電される。しかし、上述したように、この回路の夫々の分担電圧は抵抗器５Ｒがその大半を受け持つように設定してあるため、継電器コイル５Ｌは動作するに必要な電圧が得られず、接点５Ａは閉路されることなく開路されたままとなる。これによって、操作コイル１Ｌに通電されない状態が維持され、接点１Ｒ、１Ｓ、１Ｔの開路状態が維持される。従って、三相誘導電動機３の停止状態が維持される。
【００６３】
一方、三相誘導電動機３がＲ−Ｓ単相通電されている状態で、過負荷保護装置２Ｔが開路動作すると、三相誘導電動機３の巻線３Ｔの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌと電磁接触装置１の操作コイル１Ｌの通電が遮断され、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。
【００６４】
そして、その後に過負荷保護装置２Ｔが閉路動作した場合は、上述した過負荷保護装置２Ｒが閉路動作した場合と同様に動作し、接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔの開路状態が維持される。従って、三相誘導電動機３の停止状態が維持される。
【００６５】
このように、Ｔ相が途中欠相した場合には、三相誘導電動機３はまずＲ−Ｓ単相通電がなされて回転が継続され、過負荷保護装置２Ｒ又は過負荷保護装置２Ｔが一度開路動作すると、三相誘導電動機３への通電が断たれて回転が停止され、その後過負荷保護装置２Ｒ又は過負荷保護装置２Ｔが開閉動作しても三相誘導電動機３の停止状態が維持される。
【００６６】
従って、本実施例によれば、いずれの相に欠相が生じても、三相誘導電動機３の単相拘束通電を１回限りとすることができると共に、過負荷保護装置２Ｒ又は２Ｔの寿命を損なうこともないので、高信頼性、高安全性の保護装置を提供することができる。
【００６７】
次に、本発明の第２実施例を図１０から図１２を用いて説明する。この第２実施例は、次に述べる通り第１実施例と相違するものであり、その他の点については第１実施例と基本的には同一である。
【００６８】
この第２実施例では、第１実施例の回路に、送風装置１１を構成する単相誘導電動機１２に接続したものである。具体的には、単相誘導電動機１２の一側を過負荷保護装置２Ｒ又は２Ｔを含む電源ラインＲ又はＴの電源側に接続し、他側を過負荷保護装置２Ｒ又は２Ｔを含まぬ電源ラインＳの接点１Ｓの三相誘導電動機３側に接続したものである。
【００６９】
逆転防止装置５の接点５Ａ及び電磁接触装置１の接点１Ｒ、１Ｓ、１Ｔが閉路動作すると、三相誘導電動機３が始動して運転すると同時に、単相誘導電動機１２も始動して運転する。この時、単相誘導電動機１２は過負荷保護装置２Ｒ、２Ｔを介することなく通電されるので、過負荷保護装置２Ｒ、２Ｔは単相誘導電動機１２の電流を配慮することなく三相誘導電動機３の電流を配慮して電流特性を決定すればよい。これによって、過負荷保護装置２Ｒ、２Ｔの電流特性の決定が容易になると共に、三相誘導電動機３の保護をより確実に行なうことができる。
【００７０】
この状態でＲ相が図１１の×印に示すように途中欠相しても、第１実施例と同様に、逆転防止装置５の接点５Ａ及び電磁接触装置１の接点１Ｒ、１Ｓ、１Ｔが閉路動作を継続し、三相誘導電動機３はＳ−Ｔ単相通電で回転を継続する。そして、Ｔ相−過負荷保護装置２Ｔ−接点１Ｔ−電動機巻線３Ｔ−電動機巻線３Ｒ−接点１Ｒ−過負荷保護装置２Ｒ−単相誘導電動機１２−接点１Ｓ−Ｓ相の回路に通電されて単相誘導電動機１２の回転が継続される。
【００７１】
ここで過負荷保護装置２Ｔが図１１の破線の如く開路動作すると、第１実施例と同様に、三相誘導電動機３の巻線３Ｔの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌ及び電磁接触装置１の操作コイル１Ｌの通電が遮断され、夫々の接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。これに伴って、単相誘導電動機１２が同時にその回転を停止する。
【００７２】
その後、過負荷保護装置２Ｔが開路状態から図１１の実線の如く閉路動作しても、第１実施例と同様に、電磁接触装置１の操作コイル１Ｌに大きな電圧が印加されず、接点１Ｒ、１Ｓ、１Ｔが閉路動作しないので、三相誘導電動機３及び単相誘導電動機１２は再通電されることがない。
【００７３】
また、Ｓ相が図１２の×印に示すように途中欠相しても、第１実施例と同様に、逆転防止装置５の接点５Ａ及び電磁接触器１の接点１Ｒ、１Ｓ、１Ｔが閉路動作を継続し、三相誘導電動機３はＲ−Ｔ単相通電で回転を継続する。そして、Ｒ相−単相誘導電動機１２−電動機巻線３Ｓ−電動機巻線３Ｔ−接点１Ｔ−過負荷保護装置２Ｔ−Ｔ相の回路に通電されて単相誘導電動機１２の回転が継続される。
【００７４】
ここで、過負荷保護装置２Ｒが図１２の破線の如く開路動作すると、第１実施例と同様に、三相誘導電動機３の巻線３Ｒの電路が遮断されて三相誘導電動機３が停止すると同時に、逆転防止装置５の継電器コイル５Ｌ及び電磁接触装置１の操作コイル１Ｌの通電が遮断され、夫々の接点５Ａ及び接点１Ｒ、１Ｓ、１Ｔが開路動作する。これに伴って、単相誘導電動機１２が同時にその回転を停止する。
【００７５】
その後、過負荷保護装置２Ｒが図１２の破線の如く開路状態から閉路動作しても、第１実施例と同様に、逆転防止装置５の接点５Ａが閉路動作せず、電磁接触装置１の操作コイル１Ｌに通電されないことから、接点１Ｒ、１Ｓ、１Ｔが閉路動作しない。また、単相誘導電動機１２は接点１Ｓの三相誘導電動機３側と過負荷保護装置２Ｒの電源Ｒ側との間に接続されているので、接点１Ｓが開路された状態でＳ相から単相誘導電動機１２を通して操作コイル１Ｌに通電されることがない。これらによって、三相誘導電動機３及び単相誘導電動機１２には再通電されることがない。
【００７６】
又、過負荷保護装置２Ｔが開路動作した後に閉路動作しても、過負荷保護装置２Ｒの動作同様に動作し、三相誘導電動機３と共に単相誘導電動機１２は再通電されることがない。
【００７７】
Ｔ相が途中欠相しても、電磁接触装置１及び逆転防止装置５が第１実施例と同様に動作をするので、上述したＲ相の途中欠相と同様の三相誘導電動機３及び単相誘導電動機１２の動作が行なわれる。
【００７８】
従って、第２実施例によれば、過負荷保護装置２Ｒ、２Ｔによる通常運転時の三相誘導電動機３の保護を単相誘導電動機１２に係りなく確実に行ないつつ、いずれの相に欠相が生じても、三相誘導電動機３の単相拘束通電を１回限りとすることができると共に単相誘導電動機１２の通電も１回限りとすることができ、過負荷保護装置２Ｒ又は２Ｔの寿命を損ねることもないので、高信頼性、高安全性の保護装置を提供できる。
【００７９】
次に、本発明の第３実施例を図１３を用いて説明する。この第３実施例は、次に述べる通り第２実施例と相違するものであり、その他の点については第２実施例と基本的には同一である。
【００８０】
この第３実施例は、第２実施例の単相誘導電動機１２の代りに電磁弁コイル１５Ｌを接続したものである。この電磁弁コイル１５Ｌは第２実施例の単相誘導電動機１２と同じように通電されて動作する。
【００８１】
従って、第３実施例によれば、過負荷保護装置２Ｒ、２Ｔによる通常運転時の三相誘導電動機３の保護を電磁弁コイル１５Ｌに係りなく確実に行ないつつ、いずれの相に欠相が生じても三相誘導電動機３は単相拘束通電を１回限りとすることができると共に電磁弁コイル１５Ｌの通電も１回限りとすることができ、過負荷保護装置２Ｒ又は２Ｔの寿命を損なうこともないので、高信頼性、高安全性の保護装置を提供することができる。
【００８２】
次に、本発明の第４実施例を図１４を用いて説明する。この第４実施例は、次に述べる通り第２実施例と相違するものであり、その他の点については第２実施例と基本的には同一である。
【００８３】
この第４実施例は、単相誘導電動機１２を三相誘導電動機３と共に過負荷保護装置２Ｒと２Ｔを含む電磁接触装置１の三相誘導電動機３側接点３Ｒ、３Ｔに並列に接続したことにより、過負荷保護装置２Ｒ及び２Ｔには三相誘導電動機３と単相誘導電動機１２の両者の電流が流れるようにしたものである。
【００８４】
その結果、過負荷保護装置２Ｒ、２Ｔは三相誘導電動機３の電流に単相誘導電動機１２の電流を加算した上でその電流特性を決定しなければならない不都合が残るものの、両過負荷保護装置２Ｒ、２Ｔに同一電流が流れる関係から、例えば２つの過負荷保護装置２Ｒ、２Ｔを密閉形電動圧縮機６の外殻に取り付ける構造では同一特性の過負荷保護装置２Ｒ、２Ｔとすることができるため、少量多品種生産による弊害を回避することができる。
【００８５】
また、冷凍サイクルの凝縮器８及び密閉形電動圧縮機６に送風して冷却作用をする送風装置１１が何等かの理由によりファンロックが生じると、単相誘導電動機１２には拘束電流が流れて単相誘導電動機１２の巻線温度が上昇すると共に、送風装置１１による密閉形電動圧縮機６の冷却作用がなくなって三相誘導電動機３の巻線温度が上昇する。なお、通常運転時の密閉形電動圧縮機６の冷却作用は、送風装置１１による直接冷却作用と、凝縮器８が送風装置１１で冷却されることにより冷凍サイクルが機能して低温となった戻り冷媒による冷却作用とがある。これらの冷却作用により密閉形電動圧縮機６は所定温度に保持されている。
【００８６】
上述したファンロックに対して、この第４実施例の温度と電流を感知し動作する過負荷保護装置２Ｒ、２Ｔは、単相誘導電動機１２の大きな拘束電流を感知すると共に、密閉形電動圧縮機６の外殻温度の上昇を感知するので、開路動作が速くなる。その結果、送風装置１１のファンロック発生時等の単相誘導電動機１２の過熱焼損防止はもとよりのこと、三相誘導電動機３の過熱焼損も防止することができる。
【００８７】
従って、第４実施例によれば、送風装置１１のファンロック発生時に単相誘導電動機１２と共に三相誘導電動機３の過熱焼損を防止しつつ、いずれの相に欠相が生じても三相誘導電動機３は単相拘束通電を１回限りとすることができると共に、過負荷保護装置２Ｒ又は２Ｔの寿命を損なうこともないので、高信頼性、高安全性の保護装置を提供することができる。
【００８８】
なお、単相誘導電動機１２に何等かの保護装置を付帯していたものではこれを省略できる効果がある。
【００８９】
次に、本発明の第５実施例を図１５及び図１６を用いて説明する。この第５実施例は、次に述べる通り第２実施例と相違するものであり、その他の点については第２実施例と基本的には同一である。
【００９０】
この第５実施例は、単相誘導電動機１２の一側を過負荷保護装置２Ｒを含む電磁接触装置１の接点１Ｒの三相誘導電動機３側に接続すると共に、他側を過負荷保護装置２Ｔを含まぬ電磁接触装置１の接点３Ｓの三相誘導電動機３側に並列に接続したものである。これにより、一方の過負荷保護装置２Ｒには三相誘導電動機３と単相誘導電動機１２の両電流が流れ、他方の過負荷保護装置２Ｔには三相誘導電動機３のみの電流が流れる。
【００９１】
又、この第５実施例では、図３（ｂ）に示すように、一方の過負荷保護装置２Ｒを密閉形電動圧縮機６から離れた所の例えば電気品室等に取り付け、他方の過負荷保護装置２Ｔを密閉形電動圧縮機６の外殻に取り付けている。
【００９２】
一対の過負荷保護装置２Ｒ、２Ｔの動作特性はその取り付け場所の周囲温度を加味して決定されるために、取り付け場所を異にすると、一般的には同一のものを用いることができないという問題があり、少量多品種生産になりがちであった。
【００９３】
その具体的な理由を図１６を用いて説明する。密閉形電動圧縮機６に取り付けた過負荷保護装置２Ｔに流れる電流と置かれる周囲温度の座標をＡ点とすると、密閉形電動圧縮機６から離れた所に取り付けられた過負荷保護装置２Ｒの電流と温度の座標はＢ点になり、夫々の過負荷保護装置２Ｒ、２Ｔの電流−温度の動作特性は少なくてもＡ点、Ｂ点で開路動作しないものが用いられるためである。
【００９４】
そこで、この第５実施例は、図１６に示すように、密閉形電動圧縮機６から離れた所に取り付けた過負荷保護装置２Ｒに三相誘導電動機３の電流Ｘと単相誘導電動機１２の電流Ｙを加算した電流Ｚを流すことにより、この加算効果によって同一動作特性の過負荷保護装置２Ｒ、２Ｔに統合することができるようにしている。即ち、Ａ点で開路動作しない過負荷保護装置２Ｔの電流−温度に対する最低作動電流をラインＣとし、Ｂ点で開路動作しない過負荷保護装置２Ｒの電流−温度に対する最低作動電流をラインＤとすると、本実施例ではラインＤのものに統合することができる。
【００９５】
その結果、過負荷保護装置２Ｒ、２Ｔの取り付け場所誤り等に基づく不具合発生をなくすことができる。
【００９６】
従って、第５実施例によれば、過負荷保護装置２Ｒ、２Ｔを異なる所に設置しても取り付け場所誤り等に基づく不具合発生をなくすことができ、しかも、いずれの相に欠相が生じても三相誘導電動機３は単相拘束通電を１回限りとすることができると共に、過負荷保護装置２Ｒ又は２Ｔの寿命を損なうこともないので、高信頼性、高安全性の保護装置を提供することができる。
【００９７】
次に、本発明の第６実施例を図１７を用いて説明する。この第６実施例は、次に述べる通り第１実施例と相違するものであり、その他の点については第１実施例と基本的には同一である。
【００９８】
この第６実施例は、過負荷保護装置２Ｒ、２Ｔをヒータ２Ｈとバイメタル２Ｂを直列接続したものとし、ヒータ２Ｈを電源側に接続し、且つバイメタル２Ｂを三相誘導電動機３側に接続したものである。
【００９９】
バイメタル２Ｂと直列にヒータ２Ｈを入れる理由は、バイメタル２Ｂの比抵抗に限界があり、バイメタル２Ｂのみに電流を通電したのでは目的とする反転動作温度が得られない場合、その不足する発熱量をヒータ２Ｈで補うためである。一般には最低動作電流が約数アンペアを境にそれより小さいものはヒータ２Ｈ付の過負荷保護装置２Ｒ、２Ｔにされる。このヒータ２Ｈにはニッケルクロム電熱線等が用いられ、最低作動電流の仕様によってその線径は０．３Φ〜１．３Φ程度のものから選ばれる。このヒータ２Ｈは抵抗溶接や銀ロー付け等の手段により端子に接続されているが、加工時のストレスや酸化等による断線が発生することがある。
【０１００】
この第６実施例では、Ｒ相又はＴ相がヒータ２Ｈの断線で途中欠相しても、第１実施例のＲ相又はＴ相の欠相と同様に、三相誘導電動機３は夫々Ｓ−Ｔ単相通電又はＲ−Ｓ単相通電で回転を継続する。その後の過負荷保護装置２Ｒ又は２Ｔの開閉動作に対しても、第１実施例のＲ相又はＴ相の欠相と同様に保護動作が行なわれる。
【０１０１】
従って、第６実施例によれば、過負荷保護装置２Ｒ、２Ｔのヒータ２Ｈの断線及びいずれの相に欠相が生じても三相誘導電動機３は単相拘束通電を１回限りとすることができると共に、過負荷保護装置２Ｒ又は２Ｔの寿命を損なうこともないので、高信頼性、高安全性の保護装置を提供することができる。
【０１０２】
【発明の効果】
以上の説明から明らかなように本発明によれば、いずれの相に欠相が生じても、三相誘導電動機の単相拘束通電を１回限りとすることができると共に、過負荷保護装置の寿命を損なうこともないので、高信頼性、高安全性の保護装置を得ることができる。
【図面の簡単な説明】
【図１】本発明の第１実施例における保護装置の回路図である。
【図２】本発明の第１実施例を適用した冷凍装置の構成図である。
【図３】図２の冷凍装置に用いる密閉形電動圧縮機における過負荷保護装置の据付例を示す図である。
【図４】図１の逆転防止防止装置の原理説明図である。
【図５】図１の逆転防止防止装置の原理説明図である。
【図６】図１のＲ相欠相時の回路図である。
【図７】図６のＲ相欠相時の逆転防止装置の動作原理説明図である。
【図８】図１のＳ相欠相時の回路図である。
【図９】図１のＴ相欠相時の回路図である。
【図１０】本発明の第２実施例における保護装置の回路図である。
【図１１】図１０のＲ相欠相時の回路図である。
【図１２】図１０のＳ相欠相時の回路図である。
【図１３】本発明の第３実施例における保護装置の回路図である。
【図１４】本発明の第４実施例における保護装置の回路図である。
【図１５】本発明の第５実施例における保護装置の回路図である。
【図１６】図１５の保護装置の動作特性図である。
【図１７】本発明の第６実施例における保護装置の回路図である。
【図１８】従来の保護装置の回路図である。
【符号の説明】
１…電磁接触装置、１Ｌ…操作コイル、１Ｒ、１Ｓ、１Ｔ…接点、２Ｂ…バイメタル、２Ｃ…可動接点、２Ｈ…ヒータ、２Ｎ…中性点端子、２Ｒ、２Ｔ…過負荷保護装置、３…三相誘導電動機、３Ｒ、３Ｓ、３Ｔ…電動機巻線、４…開閉装置、５…逆転防止装置、５Ａ…接点、５Ｃ…コンデンサ、５Ｌ…継電器コイル、５Ｒ…抵抗器、５Ｙ…電磁継電器、６…密閉形電動圧縮機、７…電装品カバー、８…凝縮器、９…蒸発器、１０…膨張機構、１１…送風装置、１２…単相誘導電動機、１３、１４…ファン、１５…電磁弁、１５Ｌ…電磁弁コイル。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hermetic electric compressor and a protective device for a refrigeration apparatus, and is particularly suitable for a hermetic electric compressor using a three-phase induction motor and a protective device for a refrigeration apparatus such as an air conditioner or an electric refrigerator. is there.
[0002]
[Prior art]
As shown in FIG. 18, the conventional refrigeration apparatus protective device includes a hermetic electric compressor 6 using a three-phase induction motor 3 and all lines R, S, T of a three-phase power source for the three-phase induction motor 3. An electromagnetic contact device 1 having contacts 1R, 1S, 1T connected thereto, bimetallic overload protection devices 2R, 2T connected to two power supply lines R, T on the power supply side from the contacts 1R, 1T, a resistor 5R, Some include a reverse rotation prevention device 5 in which a capacitor 5C and a relay coil 5L are connected between the power supply lines R, S, and T, and a blower using a single-phase induction motor 12.
[0003]
The operation coil 1L of the electromagnetic contact device 1 is connected in series with the contact point 5A of the relay coil 5Y between the power lines R and T to which the overload protection devices 2R and 2T are connected, and one side of the operation coil 1L is one side. Is connected to the neutral point terminal 2N of the overload protection device 2R, and the other side of the operation coil 1L is connected to the neutral point terminal 2N of the other overload protection device 2T.
[0004]
Resistor 5R is one overload protection device 2R Power side Connected to. The relay coil 5L is connected to the power supply side of the other overload protection device 2T. The capacitor 5C is connected to the remaining power supply line S.
[0005]
The overload protection devices 2R and 2T are formed by connecting a heater 2H and a bimetal 2B in series. The heater side of the overload protection devices 2R and 2T is connected to the motor side, and the bimetal side is connected to the power supply side. The single-phase induction motor 12 is connected to the power supply side of the overload protection devices 2R and 2T.
[0006]
JP-A-7-262895 can be cited as a related to this prior art.
[0007]
[Problems to be solved by the invention]
However, in the conventional protection device, when the power supply S to which the overload protection devices 2R and 2T are not connected is halfway, the R-T of the three-phase induction motor 3 is opened and closed by opening and closing the overload protection device 2R or 2T. There is a problem that the single-phase energization operation and the stop thereof are repeated, and the life of the overload protection devices 2R and 2T is shortened.
[0008]
This point will be described more specifically. Even if the S-phase power supply side is halfway during normal operation of the three-phase induction motor 3, the R-phase -Resistance Resistor 5R-Relay coil 5L -T By energizing the phase circuit and continuing the closing operation of the contact 5A by the relay coil 5L, the closing operation of the contacts 1R, 1S, and 1T by the operation coil 1L is continued, and the three-phase induction motor 3 is an RT unit. Rotational motion continues with phase energization . This For example, when the overload protection device 2R is opened, the circuit of the winding 3R of the three-phase induction motor 3 is cut off and the three-phase induction motor 3 is stopped. Thereafter, the overload protection device 2R is closed. Then, the operation coil 1L is energized and the contacts 1R, 1S, and 1T are closed, so that the operation of the three-phase induction motor 3 is resumed by RT single-phase energization. Hereinafter, the R-T single-phase operation and stop of the three-phase induction motor 3 are repeated by opening and closing the overload protection devices 2R and 2T.
[0009]
In the conventional protection device, since the single-phase induction motor 12 is connected to the power supply side of the overload protection devices 2R and 2T, the S phase is lost halfway and the overload protection devices 2R and 2T are opened. However, there was a problem that the operation of the single-phase induction motor 12 was continued and the protection was not performed. In addition, since the current flowing through the two overload protection devices 2R and 2T is not added to the current flowing through the single-phase induction motor 3, if the two overload protection devices 2R and 2T are arranged at different locations, There was a problem that an overload protection device with different specifications had to be prepared.
[0010]
Further, since the conventional protection device connects the heater side of the overload protection devices 2R and 2T to the motor side and connects the bimetal side to the power supply side, the heater 2B of the overload protection devices 2R and 2T is cut off halfway. In such a case, there is a problem in that the protective properties are deteriorated as compared with the case where the R phase and the T phase are in the middle of the phase failure.
[0011]
The object of the present invention is that the single-phase restraint energization of the three-phase induction motor can be performed only once even if any phase is lost, and the life of the overload protection device is not impaired. The object is to provide a highly reliable and safe protection device.
[0012]
It should be noted that the present invention is not limited to such objects, and other objects and advantages other than those described above will become apparent from the following description.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a hermetic electric compressor using a three-phase induction motor, an electromagnetic contact device in which contacts are connected to all lines of a three-phase power source of the three-phase induction motor, and the contacts. Bimetal overload protection device connected to two power supply lines on the power supply side, and a reverse rotation prevention device in which a resistor, a capacitor and a relay coil are connected between the power supply lines, and the overload protection device was connected The operation coil of the electromagnetic contact device is connected between the power supply lines via the contact of the relay coil, the resistor is connected to the power supply line to which one of the overload protection devices is connected, and the other of the overload protection devices is connected. In the protective device for a hermetic electric compressor in which the relay coil is connected to the power line connected to the power line and the capacitor is connected to the remaining power line. Overwriting Load protection device One of the overload protection devices Connect one side of the operating coil to the neutral point terminal and Overwriting Load protection device The other overload protection device And the other side of the operating coil between the contact point of the electromagnetic contact device, the resistor is connected between the one overload protection device and the contact point of the electromagnetic contact device, and the other side Neutral end of overload protection device For child The relay coil is connected.
[0014]
The protection device of the present invention for achieving an object other than the above object will be clarified from the following description.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol in the figure of each Example shows the same thing or an equivalent.
[0016]
First, a first embodiment of the present invention will be described with reference to FIGS.
[0017]
The overall configuration, function, and operation of the refrigeration apparatus of this embodiment will be described with reference to FIGS. FIG. 2 is a configuration diagram of a refrigeration apparatus to which the first embodiment of the present invention is applied, and FIG. 3 is a diagram showing an installation example of an overload protection device in a hermetic electric compressor used in the refrigeration apparatus of FIG.
[0018]
The refrigeration apparatus of the present embodiment includes a refrigeration cycle and a blower 11 and is applied to an air conditioner, a refrigerator, and the like.
[0019]
The refrigeration cycle is formed by sequentially connecting a sealed electric compressor 6, a condenser 8, an expansion valve 10, and an evaporator 9 through refrigerant piping. The blower 11 includes a single-phase induction motor 12, a fan 13 that is rotated by the single-phase induction motor 12, and a fan 14. A refrigerant is circulated in the refrigeration cycle, and the refrigerant exchanges heat between the air sent by the blower 11 and the condenser 8 and the evaporator 9, thereby exhibiting a cooling function. That is, in the refrigeration cycle, the refrigerant is compressed by the hermetic electric compressor 6 to become high temperature and high pressure, condensed by exchanging heat with the air ventilated by the fan 13 by the condenser 8, and decompressed by the expansion valve 10. Thus, the pressure is reduced, the heat is exchanged with the air ventilated by the fan 14 in the evaporator 9, the vapor is evaporated, and the cooling function is exhibited by returning to the hermetic electric compressor 6. The expansion valve 10 is formed of a capillary tube or an expansion valve.
[0020]
The solenoid valve 15 is connected in parallel with the hermetic electric compressor 6 and is closed when the refrigeration cycle is in operation, and is opened when the refrigeration cycle is stopped, so that the pressure balance on both sides of the hermetic electric compressor 6 is achieved early. Is done. In addition, this invention is applicable also to the solenoid valve used for the other part which controls the flow of a refrigerating-cycle refrigerant | coolant.
[0021]
In addition, a pair of overload protection devices 2R and 2T are installed on the outer shell of the hermetic electric compressor 6 as shown in FIG. The overload protection devices 2R and 2T operate by detecting both an increase in the temperature of the outer shell of the hermetic electric compressor 6 and an increase in operating current.
[0022]
When there is no space for storing both of the overload protection devices 2R and 2T in the hermetic electric compressor 6, only one of the overload protection devices 2T is sealed electric as shown in FIG. It may be attached to the compressor 6 and the other overload protection device 2R may be attached to a place away from the hermetic electric compressor 6, such as an electrical component room. In this case, the overload protection device 2T senses both temperature and current, and the overload protection device 2R senses the current and performs an open circuit operation.
[0023]
The configuration of the protective device for the hermetic electric compressor 6 described above will be described with reference to FIG.
[0024]
The three-phase induction motor 3 is housed in the outer shell of the hermetic electric compressor 6 and operates the compression mechanism. The three-phase induction motor 3 has motor windings 3R, 3S, and 3T that are star-connected to lines R, S, and T of each phase of a three-phase power source.
[0025]
Contacts 1R, 1S, and 1T of the electromagnetic contact device 1 are connected to portions of all the power supply lines R, S, and T that are located outside the hermetic electric compressor 6. The electromagnetic contact device 1 includes an operation coil 1L and contacts 1R, 1S, and 1T, and closes the contacts 1R, 1S, and 1T when a predetermined voltage is applied to the operation coil 1L.
[0026]
Overload protection devices 2R and 2T are connected to the power supply side of the contact points 1R and 1T in the two power supply lines (power supply lines R and T in the illustrated example). The overload protection devices 2R and 2T have a bimetal 2B, a movable contact 2C, and a neutral point terminal 2N. The bimetal 2B moves by sensing self-heating and ambient temperature due to the flowing current, and the movable contact 2C opens and closes the power supply lines R and T.
The operation coil 1L includes a neutral point terminal 2N of the overload protection device 2R and a power line R on the motor side of the overload protection device 2T and on the power source side of the contact 1T (between the overload protection device 2T and the contact 1T). The switch 4 and the contact 5A are connected in series with each other. The switchgear 4 is for starting the three-phase induction motor 3 and is composed of a manual switch, a temperature controller, etc., and is connected between the neutral point terminal 2N of the overload protection device 2R and the operation coil 1L. ing. The contact 5A is for protecting the three-phase induction motor 3, and is connected between the power line T and the operation coil 1L. Further, the contact 5A constitutes an electromagnetic relay 5Y together with the relay coil 5L, and is closed when a predetermined voltage is applied to the relay coil 5L.
[0027]
The reverse rotation prevention device 5 includes an electromagnetic relay 5Y, a capacitor 5C, and a resistor 5R. The relay coil 5L has one side connected to the neutral point terminal 2N of the overload protection device 2T, the other side connected to the power supply line S via a capacitor 5C in series, and an overload via a resistor 5R in series. It is connected to the power line R on the motor side of the protection device 2R and on the power source side of the contact 1R (between the overload protection device 2R and the contact 1R).
[0028]
Next, the operation of the reverse rotation preventing device 5 of the hermetic electric compressor 6 will be described.
[0029]
The hermetic electric compressor 6 has various forms such as a reciprocating method, a rotary method, a scroll method, and a screw method. If the three-phase induction motor 3 that drives this is connected to a power source without phase control, the connected phase may be left or right depending on whether the phase is positive or negative.
[0030]
The reciprocating method is the only method that can compress the refrigerant regardless of the rotation direction, and all other methods are incompressible. Even in the case of the reciprocating system, there is a problem that the three-phase induction motor 3 cannot be used unless the oil supply structure of the compressor can withstand left-right rotation. Therefore, the reverse rotation preventing device 5 is used to keep the rotation direction of the three-phase induction motor 3 in a fixed direction. The reverse rotation prevention device 5 is configured such that the contact 5A is closed during the normal phase and the contact 5A is not closed during the reverse phase, and the three-phase induction motor 3 is started in the normal rotation when the normal phase is reached. .
[0031]
Here, the operation principle of the reverse rotation preventing device 5 will be described with reference to FIGS.
[0032]
The three-phase power supply is a symmetrical alternating current in which the phases between the phases are different from each other by 2π / 3 radians. This shift is caused by the nature of the phase circuit composed of the three elements of electricity, that is, the resistor 5R, the capacitor 5C, and the relay coil 5L (that is, the resistor 5R is irrelevant to the delay of the current with respect to the voltage, and the capacitor 5C On the other hand, the relay coil 5L uses the property that the current advances with respect to the voltage, and the resistor 5R, the capacitor 5C, and the relay coil 5L are connected between the phases as described above, and the relay coil 5L is connected to the relay coil 5L. The contact 5A of the reverse rotation preventing device 5 is operated by the magnitude of the flowing current.
[0033]
When the voltage in the positive phase and the current flowing through the relay coil 5L are expressed by vectors, they are as shown in FIGS. FIG. 4A shows the voltage phase in the positive phase, VR is the resistor 5R, VC is the capacitor 5C, and VT is the voltage phase of the relay coil 5L. FIG. 4B shows the current phase in the positive phase, IR is the resistor 5R, IC is the capacitor 5C, and IL is the current phase of the relay coil 5L. FIG. 4C shows the combined current IRC of IR and IC, and the combined current IRL of IR and IL. FIG. 4D shows a combined current IRCL of IRC and IRL.
[0034]
As apparent from FIG. 4, since a large current flows through the relay coil 5L during the positive phase, the electromagnetic relay 5Y is energized and the contact 5A is closed.
[0035]
If the voltage at the time of reverse phase and the electric current which flows into the relay coil 5L are represented by a vector, it will become like Fig.5 (a)-(c). FIG. 5A shows the voltage phase during reverse phase, where VR is a resistor 5R, VC is a capacitor 5C, and VT is a voltage phase to which a relay coil 5L is connected. FIG. 5B shows the current phase in the reverse phase, where IR is the resistor 5R, IC is the capacitor 5C, and IL is the current phase of the relay coil 5L. FIG. 5C shows a combined current ILC of IC and IL.
[0036]
As is clear from FIG. 5, the current flowing through the relay coil 5L during the reverse phase is canceled because the ILC and IR are in the opposite direction, and only a very small excitation current flows. Therefore, the electromagnetic relay 5Y It does not operate and as a result the contact 5A of the anti-reverse device 5 cannot be closed and remains open. And if a voltage phase changes to a positive phase, as mentioned above, a driving | operation will be started by normal rotation.
[0037]
Next, the basic operation of the protective device for the hermetic electric compressor 6 will be described with reference to FIG.
[0038]
When the switching device 4 is closed, the operation coil 1L of the electromagnetic contactor 1 is energized to energize the electromagnetic contact device 1, the contacts 1R, 1S, 1T are closed and the three-phase induction motor 3 is energized, The operation of the three-phase induction motor 3 is started. On the contrary, when the switching device 4 is opened, the energization of the operation coil 1L of the electromagnetic contact device 1 is cut off, the contacts 1R, 1S, and 1T are opened, and the energization of the three-phase induction motor 3 is cut off. The operation of the electric motor 3 is stopped.
[0039]
Here, when the open / close device 4 is closed and the three-phase induction motor 3 cannot be started for some reason and a large restraint current continues to flow through the power lines R, S, T, a pair of overload protection devices 2R, The 2T bimetal 2B generates heat. When the reverse operation temperature of the bimetal 2B set by this heat generation is reached, the movable contact 2C of the overload protection device 2R or 2T having the lower operation temperature is opened.
[0040]
By this opening operation, one power supply line R or T of the three-phase induction motor 3 is cut off, and energization of the operation coil 1L of the electromagnetic contact device 1 is also cut off. The contacts 1R, 1S, 1T are opened slightly after the operation coil 1L is cut off (this delayed operation phenomenon is called the return time of the electromagnetic contact device 1), and the remaining power lines of the three-phase induction motor 3 are cut off. The Thereby, the three-phase induction motor 3 is completely disconnected from the power supply lines R, S, T.
[0041]
When the operated overload protection device 2R or 2T bimetal 2B is cooled by ambient air and reaches the set reverse recovery temperature of the bimetal 2B, the movable contact 2C is closed again, and the operation coil of the electromagnetic contact device 1 is operated. 1L is energized. The contacts 1R, 1S, and 1T are closed slightly after energization of the operation coil 1L, and the three-phase induction motor 3 is energized again.
[0042]
At this time, if the cause of restraint of the three-phase induction motor 3 is eliminated, the three-phase induction motor 3 starts and operates normally. However, when the constraint cause continues without being eliminated, either the overload protection device 2R or 2T repeats the open circuit operation and the close circuit operation by the same constraint current as described above. In energization of the restraint current by this repetitive operation, the motor windings 3R, 3S, and 3T are set so as not to be overheated due to a temperature rise.
[0043]
Next, a protection operation in the case where one phase of the three-phase induction motor 3 is operating normally with a three-phase power source will be described with reference to FIGS. As for the three-phase power supply lines R, S, and T, one power supply line may be out of phase due to the fuse operation in the switchboard or the loosening of the screw of the cord connection mounting portion.
[0044]
The case where the R phase is broken halfway will be described with reference to FIGS.
[0045]
Even if the R phase is broken halfway as shown by the crosses in FIG. 6, the circuit of the S phase-capacitor 5C-relay coil 5L-overload protection device 2T-T phase is energized and the contact 5A is connected by the relay coil 5L. The closing operation is continued. As a result, voltages VT and VS having a phase difference of 2π / 3 radians shown in FIG. 7A are applied to the relay coil 5L, and the combined current ILC shown in FIG. 7B flows. In the range where the power supply voltage is close to the rating, the combined current ILC maintains the closed circuit of the contact 5A of the electromagnetic relay 5Y. Accordingly, the S phase-contact 1S-motor winding 3S-motor winding 3R-contact 1R-overload protection device 2R-switching device 4-operating coil 1L-contact 5A-overload protection device 2T-T phase circuit is energized. Thus, the closing operation of the contacts 1R, 1S, and 1T by the operation coil 1L is continued. As a result, the S-phase-contact 1S-motor winding 3S-motor winding 3T-contact 1T-overload protection device 2T-T phase is energized, and the three-phase induction motor 3 is rotated by ST single-phase energization. Continue.
[0046]
As described above, when the three-phase induction motor 3 is energized and single-phase energized in a half-phase state, the electric hermetic electric compressor 6 becomes overloaded as compared with normal three-phase operation, and the hermetically sealed A pair of overload protection devices 2R and 2T (see FIG. 3 (a)) attached to the outer shell of the electric compressor 6 senses both the temperature rise of the outer shell and the increase of the operating current, thereby adjusting the operating temperature. When it reaches, it opens. This is because, in single-phase operation, a current that is approximately 15% higher than the current during normal three-phase operation flows between the two phases.
[0047]
For example, when the overload protection device 2T is opened as shown by the broken line in FIG. 6 in the state where the three-phase induction motor 3 is in the ST single-phase energization state, the circuit of the winding 3T of the three-phase induction motor 3 is interrupted. Simultaneously with the stop of the three-phase induction motor 3, the energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the contact 5A and the contacts 1R, 1S, 1T are opened.
[0048]
Thereafter, when the overload protection device 2T is closed, the S phase-capacitor 5C-relay coil 5L-overload protection device 2T-T phase circuit is energized to close the contact 5A, and the S phase-capacitor 5C-resistor. 5R-overload protection device 2R-switching device 4-operating coil 1L-contact 5A-overload protection device 2T-T phase circuit is energized. Since the operation coil 1L of the electromagnetic contact device 1 does not obtain a voltage necessary to operate, the contacts 1R, 1S, and 1T of the electromagnetic contact device 1 are kept open. In other words, the series circuit current of the capacitor 5C-resistor 5R-operating coil 1L flows, but the current is very small, and the amperage of the operating coil 1L necessary for the closing operation of the contacts 1R, 1S, 1T of the electromagnetic contact device 1 I can't get a turn. Therefore, the stop of the three-phase induction motor 3 is maintained.
[0049]
On the other hand, when the overload protection device 2R is opened while the above-described three-phase induction motor 3 is in the ST single phase energization, the circuit of the winding 3R of the three-phase induction motor 3 is cut off and the three-phase induction motor 3R is cut off. At the same time as the motor 3 is stopped, the energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the contacts 5A and the contacts 1R, 1S, 1T are opened.
[0050]
After that, when the overload protection device 2R performs a closing operation, the overload protection device 2T operates in the same manner as when the above-described overload protection device 2T performs the closing operation, and the open state of the contact 5A and the contacts 1R, 1S, and 1T is maintained. . Therefore, the stopped state of the three-phase induction motor 3 is maintained.
[0051]
As described above, when the R phase is lost halfway, the three-phase induction motor 3 is first subjected to the ST single-phase energization and continues to rotate, and the overload protection device 2T or the overload protection device 2R is once opened. By operating, the power supply to the three-phase induction motor 3 is cut off and the rotation is stopped. Thereafter, even if the overload protection device 2T or the overload protection device 2R is opened and closed, the three-phase induction motor 3 is maintained in the stopped state. The
[0052]
A case where the S phase is broken halfway will be described with reference to FIG.
[0053]
Even if the S phase is broken halfway as indicated by the cross in FIG. 8, the circuit of R phase-overload protection device 2R-resistor 5R-relay coil 5L-overload protection device 2T-T is energized. The closing operation of the contact 5A by the relay coil 5L is continued. In this circuit, most of the shared voltage is handled by the resistor 5R, so that the shared voltage of the relay coil 5L is small, and the flowing current is small. However, if the closed state of the contact 5A is only maintained, the shared voltage of the relay coil 5L is small. However, the closed state of the contact 5A can be continued. As a result, the R-phase-overload protection device 2R-switching device 4-operation coil 1L-contact 5A-overload protection device 2T-T phase circuit is energized and the operation coil 1L closes the contacts 1R, 1S, 1T. Will continue. As a result, the R phase-overload protection device 2R-contact 1R-motor winding 3R-motor winding 3T-contact 1T-overload protection device 2T-T phase circuit is energized. The three-phase induction motor 3 is subjected to RT single-phase energization, but since a rotating magnetic field is formed by the current flowing through the motor windings 3S and 3R, the rotational motion is continued even with RT single-phase energization. The
[0054]
For example, when the overload protection device 2R is opened as indicated by the broken line in FIG. 8 in the state where the three-phase induction motor 3 is in the RT single-phase energization state, the circuit of the winding 3R of the three-phase induction motor 3 is cut off. At the same time as the phase induction motor 3 is stopped, the energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is interrupted, and the contact 5A and the contacts 1R, 1S, 1T are opened.
[0055]
Thereafter, when the overload protection device 2R is closed, the R phase-overload protection device 2R-resistor 5R-relay coil 5L-overload protection device 2T-T phase circuit is energized. However, since the shared voltage of each of the circuits is set so that the resistor 5R is responsible for most of the voltage as described above, the relay coil 5L cannot obtain a voltage necessary for closing the contact point 5A. 5A remains open without being closed. In other words, since the operating voltage of the relay coil 5L that closes the contact 5A is much larger than the holding voltage of the closed contact 5A, the energization of the relay coil 5L is cut off by the opening operation of the overload protection device 2R, and the contact 5A. Is opened, the operating voltage for closing the contact 5A cannot be obtained in the circuit of the relay coil 5L via the resistor 5R. Circuit state of the contact 5A This maintains the state where the operation coil 1L is not energized, and maintains the open state of the contacts 1R, 1S, and 1T. Therefore, the stopped state of the three-phase induction motor 3 is maintained.
[0056]
On the other hand, when the overload protection device 2T is opened while the three-phase induction motor 3 is energized by R-T single phase, the circuit of the winding 3T of the three-phase induction motor 3 is interrupted and the three-phase induction motor 3 At the same time, the energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the contact 5A and the contacts 1R, 1S, 1T are opened.
[0057]
Then, when the overload protection device 2T is closed, the operation is performed in the same manner as the above-described overload protection device 2R is closed, and the open state of the contact 5A and the contacts 1R, 1S, and 1T is maintained. . Therefore, the stopped state of the three-phase induction motor 3 is maintained.
[0058]
In this way, when the S phase is lost halfway, the three-phase induction motor 3 is first energized with RT single phase and continues to rotate, and the overload protection device 2R or the overload protection device 2T is once opened. When operated, the three-phase induction motor 3 is de-energized and the rotation is stopped. Thereafter, even if the overload protection device 2R or the overload protection device 2T is opened and closed, the three-phase induction motor 3 is maintained in a stopped state. .
[0059]
A case where the T-phase is broken halfway will be described with reference to FIG.
[0060]
Even if the T phase is broken halfway as indicated by the X mark in FIG. 9, the S phase-capacitor 5C-relay coil 5L-overload protection device 2T-contact 1T-motor winding 3T-motor winding 3R-contact 1R -The overload protection device 2R-R phase circuit is energized, and the closing operation of the contact 5A by the relay coil 5L is continued. Accordingly, the self-holding circuit of the R phase-overload protection device 2R-switching device 4-operating coil 1L-contact 5A-overload protection device 2T-motor winding 3T-motor winding 3S-contact 1S-S phase is energized. Thus, the closed state of the contacts 1R, 1S, and 1T by the operation coil 1L is continued. As a result, the R-phase-overload protection device 2R-contact 1R-motor winding 3R-motor winding 3S-contact 1S-S phase circuit is energized, and the three-phase induction motor 3 rotates with RS single-phase energization. Continue.
[0061]
In this state, for example, when the overload protection device 2R is opened as shown by the broken line in FIG. 9, the circuit of the winding 3R of the three-phase induction motor 3 is cut off and the three-phase induction motor 3 is stopped. The energization of the relay coil 5L and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the contact 5A and the contacts 1R, 1S, 1T are opened.
[0062]
Thereafter, when the overload protection device 2R is closed, the R phase-overload protection device 2R-resistor 5R-relay coil 5L-overload protection device 2T-contact 1T-motor winding 3T-motor winding 3S-contact 1S. -The S-phase circuit is energized. However, as described above, since the respective shared voltages of this circuit are set so that the resistor 5R is responsible for most of the voltage, the voltage required for the relay coil 5L to operate cannot be obtained, and the contact 5A is closed. It remains open without being done. As a result, the state where the operation coil 1L is not energized is maintained, and the open state of the contacts 1R, 1S, 1T is maintained. Therefore, the stopped state of the three-phase induction motor 3 is maintained.
[0063]
On the other hand, when the overload protection device 2T is opened while the three-phase induction motor 3 is energized with RS single phase, the circuit of the winding 3T of the three-phase induction motor 3 is cut off and the three-phase induction motor 3 At the same time, the energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the contact 5A and the contacts 1R, 1S, 1T are opened.
[0064]
Then, when the overload protection device 2T is closed, the operation is performed in the same manner as the above-described overload protection device 2R is closed, and the open state of the contact 5A and the contacts 1R, 1S, and 1T is maintained. . Therefore, the stopped state of the three-phase induction motor 3 is maintained.
[0065]
As described above, when the T phase is lost in the middle, the three-phase induction motor 3 is first energized with RS single phase and continues to rotate, and the overload protection device 2R or the overload protection device 2T is once opened. When operated, the three-phase induction motor 3 is de-energized and the rotation is stopped. Thereafter, even if the overload protection device 2R or the overload protection device 2T is opened and closed, the three-phase induction motor 3 is maintained in a stopped state. .
[0066]
Therefore, according to the present embodiment, the single-phase restricted energization of the three-phase induction motor 3 can be limited to one time regardless of which phase is lost, and the life of the overload protection device 2R or 2T is reached. Therefore, it is possible to provide a highly reliable and highly safe protective device.
[0067]
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different from the first embodiment as described below, and is basically the same as the first embodiment in other points.
[0068]
In the second embodiment, the circuit of the first embodiment is connected to a single-phase induction motor 12 constituting the blower 11. Specifically, one side of the single-phase induction motor 12 is connected to the power supply side of the power supply line R or T including the overload protection device 2R or 2T, and the other side is connected to the power supply line not including the overload protection device 2R or 2T. The S contact 1S is connected to the three-phase induction motor 3 side.
[0069]
When the contact 5A of the reverse rotation prevention device 5 and the contacts 1R, 1S, and 1T of the electromagnetic contact device 1 are closed, the three-phase induction motor 3 starts and operates, and the single-phase induction motor 12 also starts and operates. At this time, since the single-phase induction motor 12 is energized without passing through the overload protection devices 2R and 2T, the overload protection devices 2R and 2T do not take into account the current of the single-phase induction motor 12 and the three-phase induction motor 3 The current characteristics may be determined in consideration of the current. This facilitates the determination of the current characteristics of the overload protection devices 2R and 2T, and can more reliably protect the three-phase induction motor 3.
[0070]
In this state, even if the R phase is broken halfway as shown by the crosses in FIG. 11, the contact 5A of the reverse rotation preventing device 5 and the contacts 1R, 1S, and 1T of the electromagnetic contact device 1 are not changed as in the first embodiment. The circuit closing operation is continued, and the three-phase induction motor 3 continues to rotate by ST single-phase energization. The T phase-overload protection device 2T-contact 1T-motor winding 3T-motor winding 3R-contact 1R-overload protection device 2R-single phase induction motor 12-contact 1S-S phase circuit is energized. The rotation of the single phase induction motor 12 is continued.
[0071]
When the overload protection device 2T opens as shown by the broken line in FIG. 11, the circuit of the winding 3T of the three-phase induction motor 3 is cut off and the three-phase induction motor 3 is stopped at the same time as in the first embodiment. The energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the respective contacts 5A and contacts 1R, 1S, 1T are opened. Along with this, the single-phase induction motor 12 simultaneously stops its rotation.
[0072]
Thereafter, even when the overload protection device 2T is closed from the open state as shown by the solid line in FIG. 11, a large voltage is not applied to the operation coil 1L of the electromagnetic contact device 1 as in the first embodiment, and the contact 1R, Since 1S and 1T are not closed, the three-phase induction motor 3 and the single-phase induction motor 12 are not energized again.
[0073]
Further, even if the S phase is phase-opened as indicated by a cross in FIG. 12, the contact 5A of the reverse rotation preventing device 5 and the contacts 1R, 1S, and 1T of the electromagnetic contactor 1 are closed as in the first embodiment. The operation is continued, and the three-phase induction motor 3 continues to rotate by RT single-phase energization. The R-phase-single-phase induction motor 12-motor winding 3S-motor winding 3T-contact 1T-overload protection device 2T-T phase circuit is energized, and the rotation of the single-phase induction motor 12 is continued.
[0074]
Here, when the overload protection device 2R is opened as shown by the broken line in FIG. 12, when the circuit of the winding 3R of the three-phase induction motor 3 is cut off and the three-phase induction motor 3 is stopped as in the first embodiment. At the same time, the energization of the relay coil 5L of the reverse rotation prevention device 5 and the operation coil 1L of the electromagnetic contact device 1 is cut off, and the respective contacts 5A and contacts 1R, 1S, 1T are opened. Along with this, the single-phase induction motor 12 simultaneously stops its rotation.
[0075]
Thereafter, even if the overload protection device 2R is closed from the open state as indicated by the broken line in FIG. 12, the contact 5A of the reverse rotation preventing device 5 is not closed and the operation of the electromagnetic contact device 1 is performed as in the first embodiment. Since the coil 1L is not energized, the contacts 1R, 1S, and 1T do not close. Further, since the single-phase induction motor 12 is connected between the three-phase induction motor 3 side of the contact 1S and the power supply R side of the overload protection device 2R, the single-phase induction motor 12 is switched from the S phase to the single-phase with the contact 1S being opened. The operation coil 1L is not energized through the induction motor 12. As a result, the three-phase induction motor 3 and the single-phase induction motor 12 are not energized again.
[0076]
Even if the overload protection device 2T is closed and then closed, the same operation as that of the overload protection device 2R is performed, and the single-phase induction motor 12 and the three-phase induction motor 3 are not re-energized.
[0077]
Even if the T phase is lost in the middle, the electromagnetic contact device 1 and the reverse rotation preventing device 5 operate in the same manner as in the first embodiment. The phase induction motor 12 is operated.
[0078]
Therefore, according to the second embodiment, the three-phase induction motor 3 is reliably protected during the normal operation by the overload protection devices 2R and 2T regardless of the single-phase induction motor 12, and any phase is missing. Even if it occurs, the single-phase restraint energization of the three-phase induction motor 3 can be limited to one time and the single-phase induction motor 12 can be energized only once, and the life of the overload protection device 2R or 2T Therefore, it is possible to provide a highly reliable and highly safe protective device.
[0079]
Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the second embodiment as described below, and is basically the same as the second embodiment in other points.
[0080]
In the third embodiment, a solenoid valve coil 15L is connected in place of the single-phase induction motor 12 of the second embodiment. The electromagnetic valve coil 15L is energized and operates in the same manner as the single-phase induction motor 12 of the second embodiment.
[0081]
Therefore, according to the third embodiment, the three-phase induction motor 3 is normally protected by the overload protection devices 2R and 2T during normal operation regardless of the solenoid valve coil 15L, and any phase is lost. However, the three-phase induction motor 3 can perform single-phase restraint energization only once and energize the solenoid valve coil 15L only once, thereby impairing the life of the overload protection device 2R or 2T. Therefore, a highly reliable and highly safe protective device can be provided.
[0082]
Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is different from the second embodiment as described below, and is basically the same as the second embodiment in other points.
[0083]
In the fourth embodiment, the single-phase induction motor 12 is connected in parallel to the three-phase induction motor 3 side contacts 3R and 3T of the electromagnetic contact device 1 including the overload protection devices 2R and 2T together with the three-phase induction motor 3. In the overload protection devices 2R and 2T, the currents of both the three-phase induction motor 3 and the single-phase induction motor 12 flow.
[0084]
As a result, the overload protection devices 2R and 2T have the inconvenience of having to determine the current characteristics after adding the current of the single-phase induction motor 12 to the current of the three-phase induction motor 3, but both overload protection devices Because of the relationship that the same current flows through 2R and 2T, for example, in a structure in which two overload protection devices 2R and 2T are attached to the outer shell of the hermetic electric compressor 6, the overload protection devices 2R and 2T having the same characteristics can be obtained. Therefore, it is possible to avoid the adverse effects caused by the production of a small number of products.
[0085]
In addition, if the fan blower 11 that blows air to the condenser 8 and the hermetic electric compressor 6 in the refrigeration cycle and cools the fan for some reason causes a binding current to flow through the single-phase induction motor 12. As the winding temperature of the single-phase induction motor 12 rises, the cooling action of the hermetic electric compressor 6 by the blower 11 disappears and the winding temperature of the three-phase induction motor 3 rises. In addition, the cooling action of the hermetic electric compressor 6 during normal operation includes a direct cooling action by the blower 11 and a return in which the refrigeration cycle functions and the temperature is lowered by the condenser 8 being cooled by the blower 11. There is a cooling effect by the refrigerant. The hermetic electric compressor 6 is maintained at a predetermined temperature by these cooling actions.
[0086]
The overload protection devices 2R and 2T that operate by sensing the temperature and current of the fourth embodiment with respect to the above-described fan lock sense a large restraint current of the single-phase induction motor 12 and also use a hermetic electric compressor. Since an increase in the outer shell temperature of 6 is detected, the opening operation becomes faster. As a result, it is possible to prevent overheating of the three-phase induction motor 3 as well as preventing overheating of the single-phase induction motor 12 when a fan lock occurs in the blower 11.
[0087]
Therefore, according to the fourth embodiment, when the fan lock of the blower 11 occurs, the three-phase induction motor 12 and the three-phase induction motor 3 together with the single-phase induction motor 12 are prevented from being overheated and any phase is lost. Since the electric motor 3 can perform single-phase restraint energization only once and does not impair the life of the overload protection device 2R or 2T, a highly reliable and safe protection device can be provided. .
[0088]
It should be noted that if the single-phase induction motor 12 is provided with any protective device, this can be omitted.
[0089]
Next, a fifth embodiment of the present invention will be described with reference to FIGS. The fifth embodiment is different from the second embodiment as described below, and is basically the same as the second embodiment in other points.
[0090]
In the fifth embodiment, one side of the single-phase induction motor 12 is connected to the three-phase induction motor 3 side of the contact 1R of the electromagnetic contact device 1 including the overload protection device 2R, and the other side is connected to the overload protection device 2T. Is connected in parallel to the three-phase induction motor 3 side of the contact 3S of the electromagnetic contact device 1 that does not include. Thereby, both currents of the three-phase induction motor 3 and the single-phase induction motor 12 flow in one overload protection device 2R, and current of only the three-phase induction motor 3 flows in the other overload protection device 2T.
[0091]
In the fifth embodiment, as shown in FIG. 3B, one overload protection device 2R is attached to, for example, an electrical component room away from the hermetic electric compressor 6, and the other overload is provided. The protective device 2T is attached to the outer shell of the hermetic electric compressor 6.
[0092]
Since the operating characteristics of the pair of overload protection devices 2R and 2T are determined in consideration of the ambient temperature of the installation location, the problem that the same device cannot generally be used if the installation locations are different. There was a tendency to produce small quantities and many varieties.
[0093]
The specific reason will be described with reference to FIG. When the current flowing through the overload protection device 2T attached to the hermetic electric compressor 6 and the coordinates of the ambient temperature to be placed are point A, the overload protection device 2R attached at a location away from the hermetic electric compressor 6 This is because the coordinates of current and temperature are at point B, and the overload protection devices 2R and 2T have current-temperature operating characteristics that are not open-circuited at points A and B, at least.
[0094]
Therefore, in the fifth embodiment, as shown in FIG. 16, the current X of the three-phase induction motor 3 and the current of the single-phase induction motor 12 are added to the overload protection device 2 </ b> R attached away from the hermetic electric compressor 6. By flowing the current Z obtained by adding the current Y, the addition effect can be integrated into the overload protection devices 2R and 2T having the same operation characteristics. That is, if the minimum operating current with respect to the current-temperature of the overload protection device 2T that does not open circuit at point A is line C, and the minimum operating current with respect to the current-temperature of the overload protection device 2R that does not open circuit at point B is line D. In this embodiment, it can be integrated with that of line D.
[0095]
As a result, it is possible to eliminate the occurrence of troubles due to errors in the installation locations of the overload protection devices 2R and 2T.
[0096]
Therefore, according to the fifth embodiment, even if the overload protection devices 2R and 2T are installed in different places, it is possible to eliminate the occurrence of troubles due to an error in the installation place and the like, and any phase is lost. In addition, the three-phase induction motor 3 can perform single-phase restricted energization only once and does not impair the life of the overload protection device 2R or 2T, thus providing a high-reliability and high-safety protection device. can do.
[0097]
Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment is different from the first embodiment as described below, and is basically the same as the first embodiment in other points.
[0098]
In this sixth embodiment, the overload protection devices 2R and 2T are connected in series to the heater 2H and the bimetal 2B, the heater 2H is connected to the power supply side, and the bimetal 2B is connected to the three-phase induction motor 3 side. It is.
[0099]
The reason why the heater 2H is inserted in series with the bimetal 2B is that there is a limit to the specific resistance of the bimetal 2B. This is to make up with the heater 2H. Generally, the minimum operating current smaller than about a few amperes is used as the overload protection devices 2R and 2T with the heater 2H. A nickel chrome heating wire or the like is used for the heater 2H, and the wire diameter is selected from about 0.3Φ to 1.3Φ depending on the specification of the minimum operating current. The heater 2H is connected to the terminal by means such as resistance welding or silver brazing, but disconnection due to stress or oxidation during processing may occur.
[0100]
In the sixth embodiment, even if the R phase or the T phase is lost halfway due to the disconnection of the heater 2H, the three-phase induction motor 3 is S in the same manner as the R phase or the T phase missing in the first embodiment. Continue rotation with -T single-phase energization or RS single-phase energization. Also for the subsequent opening / closing operation of the overload protection device 2R or 2T, the protection operation is performed in the same manner as the R-phase or T-phase open phase of the first embodiment.
[0101]
Therefore, according to the sixth embodiment, the three-phase induction motor 3 is limited to single-phase restraint energization only once even if the disconnection of the heater 2H of the overload protection devices 2R and 2T and the phase failure occur in any phase. In addition, since the life of the overload protection device 2R or 2T is not impaired, a highly reliable and highly safe protection device can be provided.
[0102]
【The invention's effect】
As is clear from the above description, according to the present invention, the single-phase restricted energization of the three-phase induction motor can be performed only once even if any phase is lost, and the overload protection device Since the lifetime is not impaired, a highly reliable and highly safe protective device can be obtained.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a protection device according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a refrigeration apparatus to which the first embodiment of the present invention is applied.
3 is a diagram showing an installation example of an overload protection device in a hermetic electric compressor used in the refrigeration apparatus of FIG. 2;
4 is an explanatory diagram of the principle of the reverse rotation prevention device of FIG. 1. FIG.
FIG. 5 is a diagram illustrating the principle of the reverse rotation prevention device of FIG. 1;
FIG. 6 is a circuit diagram at the time of R-phase loss in FIG. 1;
7 is a diagram for explaining the operation principle of the reverse rotation prevention device when the R phase is missing in FIG. 6;
8 is a circuit diagram at the time of S-phase loss in FIG. 1. FIG.
FIG. 9 is a circuit diagram at the time of T-phase loss in FIG. 1;
FIG. 10 is a circuit diagram of a protection device according to a second embodiment of the present invention.
FIG. 11 is a circuit diagram at the time of R-phase loss in FIG. 10;
12 is a circuit diagram when an S phase is lost in FIG. 10;
FIG. 13 is a circuit diagram of a protection device according to a third embodiment of the present invention.
FIG. 14 is a circuit diagram of a protection device according to a fourth embodiment of the present invention.
FIG. 15 is a circuit diagram of a protection device according to a fifth embodiment of the present invention.
16 is an operation characteristic diagram of the protection device of FIG.
FIG. 17 is a circuit diagram of a protection device according to a sixth embodiment of the present invention.
FIG. 18 is a circuit diagram of a conventional protection device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electromagnetic contact device, 1L ... Operation coil, 1R, 1S, 1T ... Contact, 2B ... Bimetal, 2C ... Movable contact, 2H ... Heater, 2N ... Neutral point terminal, 2R, 2T ... Overload protection device, 3 ... Three-phase induction motor, 3R, 3S, 3T ... motor winding, 4 ... switching device, 5 ... reverse rotation prevention device, 5A ... contact, 5C ... capacitor, 5L ... relay coil, 5R ... resistor, 5Y ... electromagnetic relay, 6 DESCRIPTION OF SYMBOLS ... Sealed type electric compressor, 7 ... Electrical component cover, 8 ... Condenser, 9 ... Evaporator, 10 ... Expansion mechanism, 11 ... Blower, 12 ... Single phase induction motor, 13, 14 ... Fan, 15 ... Solenoid valve , 15L ... Solenoid valve coil.

Claims

A hermetic electric compressor using a three-phase induction motor, an electromagnetic contact device in which contacts are connected to all lines of the three-phase power source of the three-phase induction motor, and a bimetal connected to two power lines on the power source side from these contacts An overload protection device, and a reverse prevention device in which a resistor, a capacitor, and a relay coil are connected between the power lines.
While connecting the operation coil of the electromagnetic contact device between the power line connected to the overload protection device via the contact of the relay coil,
Connecting the resistor to a power line connected to one of the overload protection devices;
Connecting the relay coil to a power line connecting the other of the overload protection device,
In a protective device for a sealed electric compressor in which the capacitor is connected to the remaining power line,
One side of the operation coil is connected to a neutral point terminal of one of the overload protection devices, and the other overload protection device of the overload protection device and the electromagnetic contact device The other side of the operation coil is connected between
The resistor is connected between the one overload protection device and the contact of the electromagnetic contact device, and the relay coil is connected to a neutral point terminal of the other overload protection device. Protection device for hermetic electric compressor.

2. The protective device for a hermetic electric compressor according to claim 1, wherein the relay coil is connected to a neutral point terminal of the other overload protective device.

3. The hermetic electric compressor according to claim 1, wherein the two overload protection devices have the same characteristics and are juxtaposed to the outer shell of the hermetic electric compressor. Protective device.

4. The overload protection device is formed by connecting a heater and a bimetal in series, and the heater side of the overload protection device is connected to the power source side and the bimetal side is connected to the motor side. A protective device for a hermetic electric compressor.

A refrigeration cycle including a hermetic electric compressor using a three-phase induction motor, a blower using a single-phase induction motor that ventilates part of the refrigeration cycle, and all lines of a three-phase power source of the three-phase induction motor An electromagnetic contact device having a contact connected to the power source, a bimetal overload protection device connected to two power supply lines on the power supply side from the contact, and a reverse rotation prevention device in which a resistor, a capacitor and a relay coil are connected between the power supply lines. And
While connecting the operation coil of the electromagnetic contact device between the power line connected to the overload protection device via the contact of the relay coil,
Connecting the resistor to a power line connected to one of the overload protection devices;
Connecting the relay coil to a power line connecting the other of the overload protection device,
In the protective device of the refrigeration apparatus in which the capacitor is connected to the remaining power line,
One side of the operation coil is connected to a neutral point terminal of one of the overload protection devices, and the other overload protection device of the overload protection device and the electromagnetic contact device The other side of the operation coil is connected between
Connecting the resistor between the one overload protection device and the contact of the electromagnetic contact device, and connecting the relay coil to a neutral point terminal of the other overload protection device;
The protective device for a refrigeration apparatus, wherein the single-phase induction motor is connected between the two power lines.

6. The single-phase induction motor according to claim 5, wherein one side of the single-phase induction motor is connected to the motor side from a contact of an electromagnetic contact device of a power line including the overload protection device, and the other side of the single-phase induction motor is connected to the overload protection device. The power line not including the contact point of the electromagnetic contact device is connected to the motor side, and the one overload protection device is attached at a position away from the hermetic electric compressor, and the other overload protection device is sealed. A protective device for a refrigeration apparatus, which is attached to the outer shell of an electric compressor.

An electromagnetic contact device in which contacts are connected to all lines of a three-phase power source of a three-phase induction motor housed in a hermetic electric compressor, and a bimetallic overload protection device connected to two power lines on the power source side from these contacts; A reverse prevention device in which a resistor, a capacitor, and a relay coil are connected between the power lines, and
While connecting the operation coil of the electromagnetic contact device between the power line connected to the overload protection device via the contact of the relay coil,
Connecting the resistor to a power line connected to one of the overload protection devices;
Connecting the relay coil to a power line connecting the other of the overload protection device,
In the protective device for a sealed electric compressor in which the capacitor is connected to the remaining power supply line,
One side of the operation coil is connected to a neutral point terminal of one of the overload protection devices, and the other overload protection device of the overload protection device and the electromagnetic contact device The other side of the operation coil is connected between
The relay coil is connected to a neutral point terminal of the other overload protection device, and the resistor is connected between a contact of the one overload protection device and the electromagnetic contact device. Protection device for hermetic electric compressor.