JP3671369B2 - Electrical equipment abnormality and deterioration diagnosis device - Google Patents

Description

【００１１】
表１において、小型機〜大型回転機はそれぞれ次のような機械である。
小型機：１５ＫＷまでの電動機またはそれに相当する小型機械
中型機：１５〜７５ＫＷの電動機または強固な基礎上の３００ＫＷまでの中型機械
大型機：強固な基礎上の大型機械
大型回転機：柔軟な基礎上の大型機械
【００１２】
・精密診断
前述の簡易診断により異常があると判断した場合、その原因、場所などを特定するためには精密診断が必要となる。一般に回転機械類から発生する振動信号は複雑であり、単純な振動はほとんどない。その中から有意義な情報を得て異常の有無を精密に判断するには、周波数分析法が最も広く用いられている。振動信号を周波数分析することにより、異常の原因、場所の特定が可能となる。
【００１３】
いま、定速回転を行っている電動機等の回転機について、異常原因と発生振動数の関係の一例を表２に示す。これらの関係は、長期間にわたる過去のデ−タの蓄積により得られているものである。
【００１４】
【表２】

【００１５】
表２において、ｆ₀ ：ロ−タ（回転軸）の回転数：Ｚ：ベアリングの玉の数、ｄ：ベアリングの玉の直径、Ｄ：ベアリングのピッチ円径、ａ：ベアリングの接触角、ｎ：整数、Ｚ’：損傷歯数、である。
【００１６】
２．インバ−タの異常・劣化診断について
インバ−タは、省エネ化や生産性の向上、操作性の向上など多くの特長があり、各種産業機械のハイテク化に大きく貢献している。今やインバ−タは動力設備機械には必須機器となっており、その生産量も年々増加し、１９９９年度の日本国内における産業用インバ−タの生産量は、通産省（現経済産業省）の生産動態統計によると１８０万台を超えている（金額換算：約１０００億円）。
【００１７】
ところでインバ−タは、ＩＣ、抵抗、コンデンサ、トランジスタなどの電子部品や冷却ファン、リレ−など多数の部品によって構成されている。これらの部品は永久的に使用できるものではなく、その耐用年数や寿命は使用環境によって大きく左右され、ほとんどの電子部品はその寿命がアルレニウスの法則（１０℃二倍則：周囲温度を１０℃低下させるごとに寿命が２倍に延びる）に従うので、インバ−タの定期点検が必要となる。
【００１８】
すなわち、インバ−タの異常・劣化診断としては、トラブルの未然防止のため、ＪＥＭＡ（日本電機工業会）では「汎用インバ−タ定期点検のすすめ」のガイドブックで、表３に示すような定期点検をすすめている。
【００１９】
【表３】

【００２０】
しかし、インバ−タの異常・劣化診断においては、異常・劣化の原因や場所の特定がインバ−タを停止もしくは休止分解して専門技術者による特殊な測定器を用いなけらばならず、現実にはインバ−タが故障するまで使用し続ける場合が多い。その間はインバ−タ機能の低下、例えば省エネ機能、保護機能や出力特性等の異常、また他の機器への悪影響、例えばロボット等の誤動作や電動機トラブルの発生がしばしば見られた。
【００２１】
【発明が解決しようとする課題】
電動機及びインバ−タの異常・劣化診断は、電動機については振動法が最も広く用いられているが、ピックアップの取付けが精度に関係するため、これを振動発生源の近くに固定する必要がある。また異常・劣化個所の診断が軸受や回転軸等の機械要素部に限られ、測定にも時間がかかり測定装置を含め診断費用も高くつくので、この診断法は重要度の高い比較的大型機がメインとなる。
【００２２】
電動機についてのその他の診断法については記述を省略したが、いずれも振動法のように異常・劣化原因や場所の特定ができず、異常負荷の診断のみを行うオンライン監視システムに至っては極めて高価なものである。
【００２３】
また、インバ−タの異常・劣化診断については、前述したように異常・劣化原因や場所の特定を行うにはインバ−タを停止もしくは休止分解して、専門技術者が測定器を使用して行わねばならず甚だ面倒で時間もかかり診断に要するコストも高くつく。
【００２４】
【課題を解決するための手段】
本発明に係る電動機並びにインバ−タを対象とした電気機器の異常及び劣化診断装置は、上記の課題を解決するため、次のようにしている。
【００２５】
この電気機器の診断装置は、電気機器に流れる機器電流に含まれる各次数の高調波含有率の大きさにより電気機器の異常及び劣化の程度や、その異常・劣化原因や場所の特定を行うが、次のように精密形と簡易形の二つに分類できるので、これらについて以下に記す。
【００２６】
１，精密形
電気機器に流れる機器電流を測定する電流検出部と、前記機器電流によって発生する磁束を検出する磁界検出部と、該磁界検出部と前記電流検出部とを切換選択する切換器とを設け、該切換器よりの出力を入力処理する信号処理手段と、該信号処理手段により得られた信号を演算処理する演算処理手段とで、前記機器電流の各相に流れる電流値より演算される電流不平衡率と、前記機器電流に含まれる高調波成分を演算して得られる各次数の高調波含有率とより、前記電気機器の異常及び劣化の程度や、該異常及び劣化の原因並びに場所の特定を行う。
【００２７】
２．簡易形
電気機器に流れる機器電流によって発生する磁束を検出する磁界検出部を設け、該磁界検出部よりの出力を入力処理する信号処理手段と、該信号処理手段により得られた信号を演算処理する演算処理手段とで、前記機器電流に含まれる高調波成分を演算して得られる各次数の高調波含有率とより、前記電気機器の異常及び劣化の程度や、該異常及び劣化の原因並びに場所の特定を行う。
【００２８】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照して説明する。
【００２９】
図１は、本発明の一実施例に係る電気機器の異常及び劣化診断装置の構成を示すブロック図である。
【００３０】
１は電流検出部、２は磁界検出部である。電流検出部１による電流測定にはクランプ式が非接触で行えるので好ましいが、それ以外の方法でもよい。また、磁界検出部２はサ−チコイルセンサまたはホ−ル素子センサや磁気抵抗センサ等を用いて磁束を測定すればよいが、電流検出部１によって測定される電流と該電流によって発生する磁束は比例するので、この電流を測定磁束に代用すれば、磁界検出部２による測定が省けるので好ましい。
【００３１】
電流検出部１と磁界検出部２の選択は切換器Ｓにて行う。１０は信号処理手段であり、演算処理手段２０へは２０ａなるデ−タ信号で通信する。２４ａは操作手段３０で演算処理手段２０へ入力する条件設定デ−タを示す入力信号、２５ａは演算結果を表示手段３１に取り出す出力信号である。
【００３２】
ここで、先ず信号処理手段１０の構成について述べると次の通りである。
【００３３】
切換器Ｓを経由した信号は、選択増幅回路１１にて、電流検出部１もしくは磁界検出部２にて測定された信号レベルに応じて選択的に増幅され、その出力はＡ／Ｄ変換器１２に入力される。
【００３４】
Ａ／Ｄ変換器１２は、選択増幅回路１１によって出力されるアナログ信号をディジタル信号に変換するものである。１３は出力回路で演算処理手段２０へ２０ａなるデ−タ信号として転送する。１４はシフトレジスタ（図示しない）を中心に構成された順序制御回路、１５は波形アドレス選択回路である。
【００３５】
次に、演算処理手段２０の構成を述べると次の通りである。
【００３６】
２１は中央処理装置（以下ＣＰＵと記す）、２２は主記憶回路で、波形記憶回路２８の内容がＣＰＵ２１の制御によって演算デ−タとして記憶される。２３は補助記憶回路、２４及び２５はそれぞれ入力ポ−ト及び出力ポ−トである。補助記憶回路４３は、後述する電気機器の運転デ−タ、例えば機器定数や電圧係数、高調波対策係数などを記憶させておいたり、電気機器の定格値や運転値の条件設定をも行う回路で、この時の設定値の入力は入力ポ−ト２４を介して行う。ここで入力信号２４ａはプッシュボタンやスイッチ、タッチボタン等の操作手段３０の操作によって生じるものである。また出力ポ−ト２５はＣＰＵ２１の演算結果を外部に出力するもので、その出力信号２５ａによって、ＬＣＤ（液晶表示器）やプリンタ−等を動作さす表示手段３１を有している。２９はバスラインである。
【００３７】
また、演算処理手段２０には、アドレス発生用カウンタ２６、プログラム記憶回路２７及び波形記憶回路２８を設けている。これらの動作について次に説明する。
【００３８】
アドレス発生用カウンタ２６は、例えば８ビットのアップダウンカウンタを２個使用し、上位８ビット、下位８ビットで合計１６ビットのアドレスをつくる。このアドレス発生用カウンタ２６は次の三つの役割をもつ。
【００３９】
（１）測定波形の入力
電流検出部１もしくは磁界検出部２によって測定された電流もしくは磁束波形信号のＡ／Ｄ変換したサンプリングデ−タを、測定波形と１対１に対応した波形記憶回路２８内の番地（領域）に取り込まなけらばならない。そのためアドレス発生用カウンタ２６は、測定波形と対応したアドレスとして測定波形の横座標を下位８ビットで表し、縦座標を上位８ビットで表す。
【００４０】
（２）測定波形の出力
波形記憶回路２８内に取り込まれた波形デ−タをバスライン２９を通してＣＰＵ２１に転送する。この時、アドレス発生用カウンタ２６は１６ビットのアップカウンタとして動作し００００〜ＦＦＦＦ（１６進表示）までカウントしていく。
【００４１】
（３）プログラムの転送
プログラム記憶回路２７には、高速フ−リエ変換（ＦＦＴ：Ｆａｓｔ Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）プログラムが記憶されている。この高速フ−リエ変換による演算については、発明者が既に出願した「電気機器の劣化診断法」（特願２００１−２６５９４９）にても説明しているので、ここでは記述を省略する。
【００４２】
このプログラム記憶回路２７からバスライン２９を通してＣＰＵ２１に高速フ−リエ変換（ＦＦＴ）プログラムを転送する。この時もアドレス発生用カウンタ２６から見れば前述の測定波形の出力の場合と同様である。カウンタ動作の終了はＣＰＵ２１の指令による。
【００４３】
次に、プログラム記憶回路２７から、システムの起動時にＦＦＴプログラムがＣＰＵ２１に全て転送されると、スタ−ト指令を信号処理手段１０の直列通信回路（図示しない）に送信する。このスタ−ト指令を受けて順序制御回路が動作し、波形デ−タの波形記憶回路２８への取り込み、アドレス発生用カウンタ２６のリセット、そして波形記憶回路２８内の波形デ−タをＣＰＵ２１へ送信するというプロセスを繰り返し行う。また、波形アドレス選択回路１５はアドレス発生用カウンタ２６の動作により、波形アドレスの領域を選択するものである。
【００４４】
以上が、本発明に係る診断装置の構成を示すブロック図の説明であるが、次に電気機器の入力及び出力電流に関して、本発明者が既に完成させた出願特許（特願２００１−２６５９４９）を基に一部補足し図面を参照して説明すると以下の通りとなる。
【００４５】
図２は、インバ−タに係るブロック図である。５１は三相交流電源、５３は電動機５２を制御するインバ−タであって、コンバ−タ部５４と平滑コンデンサ５５、及びインバ−タ部５６を制御するコントロ−ル部５７で構成されている。コントロ−ル部５７はＩＣ、抵抗、コンデンサ、トランジスタなどの電子部品を搭載したコントロ−ル基板である。また、Ｉ_n1及びＩ_n2はそれぞれインバ−タ５３の入力電流及び出力電流（電動機電流）であって、インバ−タ５３が、例えば現在主流となっている正弦波ＰＷＭインバ−タの場合のＩ_n1及びＩ_n2は、図２にて示したような電流波形となる。
【００４６】
ところで、図２で示したようなコンバ−タ部５４を有するインバ−タ５３の入力側における高調波電流Ｉ_n1は、三相交流電源５１の電圧がバランスし、その電源インピ−ダンスや電動機５２の負荷率等を無視した理想値として考えると、周知のように次式のようになる。
【００４７】
【数１】

ただし、Ｉ₁₁は基本波電流である。
【００４８】
しかし、（１）式は前述した仮定条件以外に、図２のインバ−タ部５６を構成する電力素子デバイスのデッドタイムや、インバ−タ５３の運転周波数に関係する制御角、及び高調波対策が施されているか否か、更には三相交流電源５１の出力に他の負荷機器（インバ−タ等も含む）の接続有無や、電流高調波の検出が電流によるか磁界によるかといった測定方式等の諸要素は全く考慮されていない。
【００４９】
だが、上述した諸要素を全て考慮した高調波電流を理論的に算出することは困難なため、本発明者は長年にわたるデ−タの分析と実験的解析手法により、高調波電流Ｉ_n1が次式に従うことを見い出した。
【００５０】
【数２】

【００５１】
（２）式においてＬ_f は電源負荷係数で、図２で示した三相交流電源５１の出力母線に電動機５２とは別に負荷（インバ−タ等も含む）が接続されている場合は、それらの接続負荷を合計した等価容量によってＬ_f は次のような値をとる。
【００５２】
（１）等価容量が１５ＫＷまでの負荷：Ｌ_f ＝２．０
（２）等価容量が１５〜５５ＫＷの負荷：Ｌ_f ＝１．８
（３）等価容量が５５〜１１０ＫＷの負荷：Ｌ_f ＝１．５
（４）等価容量が１１０〜３００ＫＷの負荷：Ｌ_f ＝１．２
（５）等価容量が３００ＫＷ以上の負荷：Ｌ_f ＝１．０
【００５３】
尚、接続負荷が無い場合はＬ_f ＝１．０を採用すればよい。しかし負荷が分からない場合や簡略計算でもよい場合はＬ_f ＝１．０として考えればよいが、出来る限り接続負荷容量を把握しておくことが好ましい。
【００５４】
また、（２）式のＤ_f は検出器係数で、機器電流に含まれる高調波成分を、クランプ式電流測定によるか、もしくは機器電流によって発生する磁束をサ−チコイル等の磁界測定によるかで異なる。即ち、磁界測定によって得られた数値は、電流測定による数値より、磁束の空間伝搬減衰分だけ低い値を示す。本発明者は、前記両方式の測定値を統計的に比較分析した結果、Ｄ_f として次の値を採用するに至った。但し、電流変動が激しい場合は測定を何度か繰返し平均をとる。
（１）クランプ式電流測定による場合：Ｄ_f ＝１．６
（２）サ−チコイル等の磁界測定による場合：Ｄ_f ＝１．０
【００５５】
更に、（２）式においてＭa 、Ｍb 及びＭc は電動機単独運転かインバ−タ運転かによって定まる機器定数で、それぞれ次のような値となる。
（１）電動機単独運転の場合
Ｍ_a ＝０．０２、Ｍ_b ＝０．０１、Ｍ_c ＝０
（２）インバ−タ運転の場合
Ｍ_a ＝０．２、Ｍ_b ＝０．１、Ｍ_c ＝１．０
【００５６】
そして、（２）式中のＫ_V は次の（６）式で示される電圧係数で、（６）式中Ｘの数値は電動機もしくはインバ−タの入力電圧が２００Ｖ系の場合は２００、４００Ｖ系及び３０００Ｖ系の場合は、それぞれ４００及び３０００となる。
【００５７】
【数３】

【００５８】
また、（２）式でのＫ_h はインバ−タ運転時の高調波対策係数で、下記に示すような値をとる。
（１）高調波対策が無い場合はＫ_h ＝１
（２）高調波対策が有る場合は、その対策部品により異なるが、平均的には次のようになる。但し、数値は第５次及び第７次高調波に対するものであり、第１１次以上及びこれら以外の各次数高調波の場合は（ ）内の数値となる。
ａ．ラインフィルタ設置時はＫ_h ＝０．９０（０．９５）
ｂ．ＡＣリアクトル設置時はＫ_h ＝０．６０（０．８５）
ｃ．ＤＣリアクトル設置時はＫ_h ＝０．５５（０．９５）
ｄ．ＡＣ＋ＤＣリアクトル併用設置時はＫ_h ＝０．４０（０．９０）
ｅ．ＥＭＩフィルタ設置時はＫ_h ＝０．６０（０．８０）
【００５９】
なお、（２）式のＫ_S は電源インピ−ダンスＺ（％）を、Ｋ_W は負荷率（％）であり、計算時に用いる数値としてはそれぞれ１００で除した値となる。
【００６０】
ところで、インバ−タ運転において（２）式では表されないが考慮すべきは特に第６次高調波成分である。この第６次高調波成分はインバ−タの運転周波数が電源周波数の１／２、即ち商用電源周波数が６０Ｈｚ地区では３０Ｈｚ運転とした時、電動機の回転軸に少しでもベアリングやカップリング等に起因するアンバランスがあると第６次高調波含有率は１／ｎ（ｎは高調波次数）、即ち約１６％にも達する場合がある。この場合は他の次数高調波含有率も高くなる傾向にあるため、インバ−タ運転をする時は次式を満足させるよう注意する必要がある。
インバ−タの運転周波数≠（商用電源周波数）／ｍ（整数）
【００６１】
以上で入力側の高調波電流が求まり、各次数の高調波含有率が算出できる。ここで電気機器として電動機及びインバ−タの異常・劣化診断の観点のみから言えば、前記電気機器の入力側高調波次数は第１０次迄考慮すれば充分であるが、これについては後述する。
【００６２】
次に、図２にもどりインバ−タ５３の出力電流、即ち電動機５２に流れる電動機電流Ｉ_n2は、本発明者が多くのデ−タを蓄積し、確立統計解析を行った結果次式で表せることを見い出した。
【００６３】
【数４】

ここで、Ｉ₁₂：電動機電流の基本波電流、ｎ：高調波次数
ｈ：高調波係数、Ｋ_m ：電動機定数
【００６４】
（７）式中のＫm は次のような数値となる。
（１）Ｋm ＝０．０５（ただし、ｎ＝２）
（２）Ｋm ＝０．１５（ただし、ｎ＝３）
（３）Ｋm ＝１．０（ただし、ｎ＝２、３以外）
上記（１）、（２）のみＫm が異なっているのは、元々三相交流電源によって供給される電圧及び電流波形は、いづれも対称波であるためｎ＝２とその整数倍の高調波は発生せずＫm ＝０となる。更に三相交流電源の電圧、電流が平衡していて不平衡率がゼロの場合はｎ＝３とその整数倍の高調波も生じなくＫm ＝０となる。しかし、現実的には他の電気機器（例えばインバ−タ）や誘導電磁界の影響によりＫm ≠０となるのである。
【００６５】
また、（７）式中の高調波係数ｈは、次のような三つの高調波次数（ｎ）領域により異なった値になる。
（１）５＞ｎの場合はｈ＝２
（２）１１＞ｎ≧５の場合はｈ＝１
（３）ｎ≧１１の場合はｈ＝１．６
【００６６】
以上のようにインバ−タ出力側の高調波電流が求まる。ここで、インバ−タが正弦波ＰＷＭ制御方式のような電圧形インバ−タの場合は出力インピ−ダンスが小さく、負荷である電動機に対しては電圧源として作用するため、出力側電流に含まれる高調波含有率は小さい。尚、（７）式中のＫ_V 、Ｋ_S 及びＫ_W は（２）式にて表したものと同じ意味のものであるが、インバ−タが電圧源と考えた場合はＫ_S ＝０と考えてよい。しかし、電流形インバ−タの場合はＫ_S ＝１と見なし、（７）式にインバ−タ係数Ｃ_S （記述しない）を乗ずればよい。この時Ｃ_S ＝２として計算すればほぼ実状に即した結果となることを本発明者は確認している。
【００６７】
また、電圧係数Ｋ_V は（６）式で示されるから、（６）式中のＸは運転周波数に比例した電圧と考えても差しつかえない。従って、例えば商用電源周波数が６０Ｈｚ地域の２００Ｖ系で、３０Ｈｚ運転の場合は出力電圧が１００Ｖとなり、電圧係数Ｋ_V は約１．４となる。
【００６８】
以上、本発明に係る機器電流に流れる各次数の高調波電流の演算法について述べたが、その演算結果に基づく電気機器の異常・劣化判定値については後述の実施例にて述べる。
【００６９】
ところで、前述したように電気機器の異常及び劣化の程度や、その異常・劣化原因や場所の特定を精密に行うには、前記電気機器の各相（Ｒ相、Ｓ相、Ｔ相）電流の実効値を測定する。この電流の測定にはクランプ式電流計が非接触で行えるので好ましい。測定から得られた各相電流より、電流不平衡率は次式で求める。
電流不平衡率＝｛（Ｉmax −Ｉmin ）／Ｉmin ｝×１００（％） （８）
ここで、Ｉmax 及びＩmin は、それぞれ各相電流の最大値及び最小値である。
【００７０】
【実施例】
本発明の実施例として、電動機及びインバ−タの異常・劣化判定値と、この判定値に基づき「正常」、「要注意」及び「不良」に区分し、異常・劣化原因や場所の特定に関して説明すれば次の通りである。尚、本発明の異常・劣化判定値の「正常」、「要注意」及び「不良」についての高調波含有率の数値は実施例に限定されることはない。
【００７１】
また、判定値区分において、「正常」はＡレベル、「要注意」はＢレベル、「不良」はＣレベルと記すが、その中で「要注意」のＢレベルは、機器の劣化度に応じ軽度な劣化（約１年は運転に支障がない劣化）をＢ１（ランク・）、中度な劣化（約６ヵ月は運転には支障がないが傾向管理が必要な劣化）をＢ２（ランク・）、重度な劣化（約３ヵ月程度の運転は可能であるが、機器のトラブル発生が懸念されるため部品交換や修理の準備が必要な劣化）をＢ３（ランク・）の３ランクに分けている。
【００７２】
表４に電気機器の異常・劣化判定基準表を示す。表中の電動機入力における高調波診断時の計算値は（２）式もしくは（７）式により求めた値であるが、電動機単独運転の場合は（７）式により求めるのが簡単で便利である。また、インバ−タ使用時の高調波診断の入力及び出力における計算値は、それぞれ（２）式及び（７）式により求める。また、本発明に係る装置が精密形の場合は表４のように電流診断も行う必要があるが、簡易形の場合は高調波診断のみでよい。
【００７３】
【表４】

【００７４】
表５は表４の判定基準に基づいて算出した電動機の診断判定表である。表５において高調波診断に用いた「正常」判定の基準となる計算値は、（７）式中で電源負荷係数Ｌ_f ＝１．０、検出器係数Ｄ_f ＝１．０（サ−チコイルによる非接触磁界検出器を使用）として求めた数値によった。また、電流診断にはクランプ式センサを用いた。
【００７５】
【表５】

【００７６】
表６は電動機の劣化原因・場所の特定表である。本表は高調波次数と電動機の劣化原因・場所の関係を表したもので、本発明者の長年に亘デ−タの蓄積による統計分析と実験デ−タによる確率解析により始めて明らかになったものである。特に、第２次〜第５次高調波は電動機に、第７〜第１０次高調波は負荷に起因する劣化であることが明確になったことは本発明の大きな成果の一つである。
【００７７】
【表６】

【００７８】
表７は電動機、インバ−タの劣化原因・場所の特定表である。本表はインバ−タ制御による電動機運転時の高調波次数と電動機、インバ−タの劣化原因・場所の関係を表したもので、表６と同様に技術ノウハウを実験的解析手法により体系化したものである。
【００７９】
【表７】

【００８０】
【発明の効果】
本発明の電気機器の異常及び劣化診断装置は、電動機並びにインバ−タを対象としたもので次のような効果を奏する。
【００８１】
（１）本発明の非接触測定器は回路構成がシンプルで簡便かつ安価なため、電動機並びにインバ−タを対象とした電気機器の異常及び劣化診断が、専門技術者を必要とすることなく誰にでも安全に行える。
（２）対象とする電気機器の劣化診断用以外に、動力設備機械の検収用、鉄道車輛やエレベ−タ等のような法令で定められた運輸、輸送設備の定期点検用にも用途がある。
（３）長年に亘った電気機器の異常及び劣化デ−タの蓄積による統計解析と、実験デ−タによる確率解析に基づき実験理論式が導出でき、本発明装置が多くの機器で実証確認されたので、ＩＳＯ規格やＪＩＳ規格にすることが可能である。
【図面の簡単な説明】
【図１】電気機器の異常及び劣化診断装置の構成を示すブロック図である。
【図２】インバ−タに係るブロック図である。
【符号の説明】
１ 電流検出部
２ 磁界検出部
１０ 信号処理手段
２０ 演算処理手段
２１ 中央処理装置（ＣＰＵ）
２２ 主記憶回路
２３ 補助記憶回路
２４ 入力ポ−ト
２５ 出力ポ−ト
３０ 操作手段
３１ 表示手段
５１ 三相交流電源
５２ 電動機
５３ インバ−タ
５４ コンバ−タ部
５５ 平滑コンデンサ
５６ インバ−タ部
５７ コントロ−ル部[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to a technical field related to equipment diagnosis, and relates to an apparatus for diagnosing abnormality and deterioration of electrical equipment for an induction motor (hereinafter referred to as an electric motor) and an inverter.
[0002]
[Prior art]
Recent electrical equipment facilities have been continuously produced or concentrated to pursue high productivity, and energy efficient equipment such as inverters has been introduced along with high-performance, wide-range automation systems, and highly reliable equipment and devices. The mass production to make is required in every industry. Such mass production equipment is generally based on continuous operation, and failure of electric equipment (pause) often leads to an outage of the entire process. Once a failure occurs, it is surmised that the outage loss will be immeasurable due to loss of reliability from customers and the occurrence of disasters in some cases, in addition to production failures, and it will be a fatal problem.
[0003]
Also, when a company purchases a new equipment (machine) and accepts it, there is no standardized acceptance standard or standard, and at present, the acceptance is confirmed when the equipment (machine) operates as specified. It is said. However, recent automatic devices (machines) have a combined system configuration in which many devices are connected by an interface scale, so there is a case where consistency (matching) between the devices is not achieved. Later, trouble occurred many times, and there was a case that led to a fire accident.
[0004]
In addition, for example, railway vehicles and elevators, which are transported and transported by people, are required to be regularly inspected by law. For motor equipment and inverters, it is confirmed whether there is a rise in temperature or abnormal noise. There is a problem in terms of safety.
[0005]
Here, the purpose of the abnormality and deterioration diagnosis of the electrical equipment is described as follows.
(1) Cost reduction
a. Increased operating rate by reducing equipment downtime
b. Reduction of maintenance costs such as material costs and labor costs
c. Replacement cycle extension
d. Inspection and maintenance reduction
(2) Prior trouble prevention
(3) Safety improvement
(4) Improved reliability
(5) Productivity improvement
(6) Quality improvement
[0006]
The above is the background and purpose of the necessity for diagnosis of abnormality / deterioration of electrical equipment, but here, first, regarding the prior art of abnormality / degradation diagnosis of the motor and inverter according to the present invention, the following items 1 to 2 Each will be briefly described.
[0007]
1. About abnormality and deterioration diagnosis of motors
As an abnormality / deterioration diagnosis method for an electric motor, (1) vibration method, (2) acoustic method, (3) temperature method, (4) torque (strain) method, (5) current method, (6) waveform method, etc. However, since the vibration method is the most popular and popular method among them, the vibration method will be described here. Other diagnostic methods are described in patents already filed by the inventor (Japanese Patent Application No. 2000-386603, Japanese Patent Application No. 2001-265949).
[0008]
(1) Vibration method
In the vibration method, a rotating machine vibration of a load facility including an electric motor or an electric motor is mounted as close as possible to an electrodynamic type, piezoelectric type or displacement type vibration pickup, and the over-all value of the vibration There is a simple diagnosis for determining an abnormality by the above and a precise diagnosis for identifying the cause and location of the abnormality / degradation by vibration frequency analysis, but these diagnoses are limited to mechanical elements such as a bearing and a rotating shaft.
[0009]
・ Simple diagnosis
As a criterion for determining whether the vibration is abnormal or normal due to the over-all value of the vibration, there are places where the company has independently decided based on the accumulation and experience of past data. In most cases, JIS standards and VDI standards (standards of German Engineers Association) are used as a reference. However, these standards give an average rating and do not apply to all rotating machines. Table 1 shows the ISO standard (ISO-2372) as a reference example.
[0010]
[Table 1]

[0011]
In Table 1, the small machine to the large rotary machine are the following machines, respectively.
Small machine: Electric motor up to 15KW or equivalent small machine
Medium size machine: Medium size machine up to 300KW on 15-1575W motor or solid foundation
Large machine: Large machine on a solid foundation
Large rotating machine: Large machine on a flexible foundation
[0012]
・ Precise diagnosis
If it is determined by the simple diagnosis described above that there is an abnormality, a precise diagnosis is required to identify the cause, location, and the like. In general, vibration signals generated from rotating machinery are complex, and there is almost no simple vibration. The frequency analysis method is most widely used to obtain meaningful information from them and accurately determine the presence or absence of abnormality. By analyzing the frequency of the vibration signal, it is possible to identify the cause and location of the abnormality.
[0013]
Table 2 shows an example of the relationship between the cause of abnormality and the generated frequency for a rotating machine such as an electric motor that is rotating at a constant speed. These relationships are obtained by accumulating past data over a long period of time.
[0014]
[Table 2]

[0015]
In Table 2, f ₀ : Number of rotations of rotor (rotating shaft): Z: Number of balls of bearing, d: Diameter of bearing balls, D: Diameter of bearing pitch circle, a: Contact angle of bearing, n: Integer, Z ′: The number of damaged teeth.
[0016]
2. Inverter abnormality / deterioration diagnosis
The inverter has many features such as energy saving, productivity improvement, and operability improvement, and greatly contributes to the high technology of various industrial machines. Inverters are now indispensable equipment for power equipment, and their production volume has been increasing year by year. The production volume of industrial inverters in Japan in 1999 was the production of the Ministry of International Trade and Industry (now Ministry of Economy, Trade and Industry). According to dynamic statistics, it exceeds 1.8 million units (amount conversion: about 100 billion yen).
[0017]
By the way, an inverter is comprised by many components, such as electronic components, such as IC, resistance, a capacitor | condenser, a transistor, a cooling fan, and a relay. These components are not permanently usable, and their useful life and life are greatly affected by the usage environment, and most electronic components have their lifespan of Arrenius's law (10 ° C double rule: lower the ambient temperature by 10 ° C) The life of the inverter is doubled every time the inverter is used. Therefore, periodic inspection of the inverter is required.
[0018]
In other words, in order to prevent troubles from occurring as an abnormality / deterioration diagnosis of inverters, JEMA (Japan Electrical Manufacturers' Association) provides a guidebook “General Inverter Periodic Inspection” guidebook as shown in Table 3. We are inspecting.
[0019]
[Table 3]

[0020]
However, in the inverter abnormality / degradation diagnosis, the cause and location of the abnormality / deterioration must be specified by stopping or suspending the inverter and using a special measuring instrument by a specialist. In many cases, the inverter continues to be used until the inverter fails. In the meantime, the inverter function deteriorated, for example, an abnormality such as an energy saving function, a protection function, and output characteristics, and an adverse effect on other devices, for example, malfunction of a robot or the occurrence of a motor trouble was often observed.
[0021]
[Problems to be solved by the invention]
For the motor / inverter abnormality / deterioration diagnosis, the vibration method is most widely used for motors. However, since the mounting of the pickup is related to accuracy, it is necessary to fix it near the vibration source. In addition, the diagnosis of abnormalities and deteriorated parts is limited to machine elements such as bearings and rotating shafts, and it takes time to measure and the cost of diagnosis including the measuring device is high, so this diagnosis method is a relatively large machine with high importance. Is the main.
[0022]
Other diagnostic methods for motors were omitted from the description, but all of them were extremely expensive for online monitoring systems that could not identify the cause of abnormality / degradation and location like the vibration method, and only diagnose abnormal loads. Is.
[0023]
For inverter abnormality / degradation diagnosis, as described above, the cause of the abnormality / degradation and the location can be identified by stopping or suspending the inverter and using a measuring instrument by a professional engineer. This must be done, is cumbersome, time consuming, and the cost of diagnosis is high.
[0024]
[Means for Solving the Problems]
In order to solve the above-described problems, an apparatus for diagnosing abnormality and deterioration of an electric device intended for an electric motor and an inverter according to the present invention is as follows.
[0025]
This electrical equipment diagnostic device identifies the degree of abnormality and deterioration of electrical equipment, the cause and location of the abnormality / degradation, depending on the magnitude of the harmonic content of each order contained in the equipment current flowing in the electrical equipment. Since it can be classified into two types, precision type and simple type as follows, these are described below.
[0026]
1, precision type
A current detection unit for measuring a device current flowing in the electric device, a magnetic field detection unit for detecting a magnetic flux generated by the device current, and a switch for selecting and switching between the magnetic field detection unit and the current detection unit, A current unbalance calculated from current values flowing in each phase of the device current by signal processing means for input processing of the output from the switching device and arithmetic processing means for arithmetic processing of the signal obtained by the signal processing means From the rate and the harmonic content of each order obtained by calculating the harmonic component included in the equipment current, the degree of abnormality and deterioration of the electrical equipment, the cause and location of the abnormality and deterioration can be specified. Do.
[0027]
2. Simplified type
Provided with a magnetic field detection unit that detects magnetic flux generated by a device current flowing in the electric device, and a signal processing unit that performs input processing on an output from the magnetic field detection unit, and arithmetic processing that performs arithmetic processing on a signal obtained by the signal processing unit Means to determine the degree of abnormality and deterioration of the electrical equipment, the cause and location of the abnormality and deterioration, based on the harmonic content of each order obtained by calculating the harmonic component included in the equipment current. I do.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0029]
FIG. 1 is a block diagram illustrating a configuration of an electrical equipment abnormality and deterioration diagnosis apparatus according to an embodiment of the present invention.
[0030]
Reference numeral 1 denotes a current detection unit, and 2 denotes a magnetic field detection unit. The current measurement by the current detector 1 is preferable because the clamp method can be performed in a non-contact manner, but other methods may be used. The magnetic field detector 2 may measure the magnetic flux using a search coil sensor, a hall element sensor, a magnetoresistive sensor, or the like, but the current measured by the current detector 1 is proportional to the magnetic flux generated by the current. Therefore, it is preferable to substitute this current for the measurement magnetic flux because the measurement by the magnetic field detector 2 can be omitted.
[0031]
Selection between the current detection unit 1 and the magnetic field detection unit 2 is performed by the switch S. A signal processing unit 10 communicates with the arithmetic processing unit 20 using a data signal 20a. Reference numeral 24 a denotes an input signal indicating condition setting data input to the arithmetic processing means 20 by the operation means 30, and reference numeral 25 a denotes an output signal for extracting the calculation result to the display means 31.
[0032]
Here, first, the configuration of the signal processing means 10 will be described as follows.
[0033]
The signal passing through the switch S is selectively amplified by the selective amplifier circuit 11 according to the signal level measured by the current detection unit 1 or the magnetic field detection unit 2, and the output thereof is A / D converter 12. Is input.
[0034]
The A / D converter 12 converts the analog signal output from the selective amplifier circuit 11 into a digital signal. Reference numeral 13 denotes an output circuit which transfers it to the arithmetic processing means 20 as a data signal 20a. Reference numeral 14 denotes a sequence control circuit mainly composed of a shift register (not shown), and reference numeral 15 denotes a waveform address selection circuit.
[0035]
Next, the configuration of the arithmetic processing means 20 will be described as follows.
[0036]
Reference numeral 21 denotes a central processing unit (hereinafter referred to as CPU), 22 is a main memory circuit, and the contents of the waveform memory circuit 28 are stored as operation data under the control of the CPU 21. Reference numeral 23 is an auxiliary memory circuit, and 24 and 25 are input ports and output ports, respectively. The auxiliary storage circuit 43 stores operation data of electrical equipment, which will be described later, such as equipment constants, voltage coefficients, harmonic countermeasure coefficients, etc., and also sets conditions for rated values and operation values of electrical equipment. At this time, the set value is input via the input port 24. Here, the input signal 24a is generated by the operation of the operation means 30 such as a push button, a switch, or a touch button. The output port 25 outputs the calculation result of the CPU 21 to the outside, and has a display means 31 for operating an LCD (Liquid Crystal Display), a printer or the like by the output signal 25a. 29 is a bus line.
[0037]
The arithmetic processing means 20 is provided with an address generation counter 26, a program storage circuit 27, and a waveform storage circuit 28. These operations will be described next.
[0038]
The address generation counter 26 uses, for example, two 8-bit up / down counters, and creates an address of 16 bits in total by upper 8 bits and lower 8 bits. The address generation counter 26 has the following three roles.
[0039]
(1) Measurement waveform input
Sampling data obtained by A / D conversion of the current or magnetic flux waveform signal measured by the current detection unit 1 or the magnetic field detection unit 2 is stored in an address (area) in the waveform storage circuit 28 corresponding to the measurement waveform one-to-one. Must be captured. For this reason, the address generation counter 26 represents the abscissa of the measurement waveform as lower 8 bits and the ordinate as upper 8 bits as an address corresponding to the measurement waveform.
[0040]
(2) Measurement waveform output
The waveform data fetched into the waveform storage circuit 28 is transferred to the CPU 21 through the bus line 29. At this time, the address generation counter 26 operates as a 16-bit up counter and counts from 0000 to FFFF (hexadecimal display).
[0041]
(3) Program transfer
The program storage circuit 27 stores a fast Fourier transform (FFT) program. The calculation by the high-speed Fourier transform is also described in the “electric device deterioration diagnosis method” (Japanese Patent Application No. 2001-265949) already filed by the inventor, and is therefore omitted here.
[0042]
A high-speed Fourier transform (FFT) program is transferred from the program storage circuit 27 to the CPU 21 through the bus line 29. At this time, as seen from the address generation counter 26, it is the same as the case of the output of the measurement waveform described above. The counter operation is ended by a command from the CPU 21.
[0043]
Next, when all the FFT programs are transferred from the program storage circuit 27 to the CPU 21 at the time of system startup, a start command is transmitted to a serial communication circuit (not shown) of the signal processing means 10. In response to this start command, the sequence control circuit operates to load the waveform data into the waveform storage circuit 28, reset the address generation counter 26, and transfer the waveform data in the waveform storage circuit 28 to the CPU 21. Repeat the process of sending. The waveform address selection circuit 15 selects a waveform address region by the operation of the address generation counter 26.
[0044]
The above is the description of the block diagram showing the configuration of the diagnostic apparatus according to the present invention. Next, regarding the input and output currents of the electrical equipment, the patent application already completed by the present inventor (Japanese Patent Application No. 2001-265949) has been completed. It will be as follows if a part is supplemented and it demonstrates with reference to drawings.
[0045]
FIG. 2 is a block diagram relating to the inverter. Reference numeral 51 denotes a three-phase AC power source, and 53 denotes an inverter that controls the motor 52, which includes a converter unit 54, a smoothing capacitor 55, and a control unit 57 that controls the inverter unit 56. . The control unit 57 is a control board on which electronic components such as an IC, a resistor, a capacitor, and a transistor are mounted. I _n1 And I _n2 Are the input current and output current (motor current) of the inverter 53, respectively. The inverter 53 is, for example, the current mainstream sine wave PWM inverter. _n1 And I _n2 Is a current waveform as shown in FIG.
[0046]
Incidentally, the harmonic current I on the input side of the inverter 53 having the converter 54 as shown in FIG. _n1 As is well known, when the voltage of the three-phase AC power supply 51 is balanced and the power supply impedance and the load factor of the motor 52 are ignored, the following equation is known.
[0047]
[Expression 1]

However, I ₁₁ Is the fundamental current.
[0048]
However, in addition to the above-mentioned assumptions, the equation (1) is a countermeasure against the dead time of the power element device constituting the inverter unit 56 of FIG. 2, the control angle related to the operating frequency of the inverter 53, and harmonic measures Whether or not other load devices (including inverters etc.) are connected to the output of the three-phase AC power source 51, and whether current harmonics are detected by current or magnetic field. These factors are not considered at all.
[0049]
However, since it is difficult to theoretically calculate the harmonic current in consideration of all of the above-described factors, the present inventor has performed harmonic data I through long-term data analysis and experimental analysis techniques. _n1 Has found that
[0050]
[Expression 2]

[0051]
In the formula (2), L _f Is a power load coefficient, and when a load (including an inverter, etc.) is connected to the output bus of the three-phase AC power source 51 shown in FIG. L by capacity _f Takes the following values:
[0052]
(1) Load up to 15 kW equivalent capacity: L _f = 2.0
(2) Load with an equivalent capacity of 15 to 55 KW: L _f = 1.8
(3) Load with an equivalent capacity of 55 to 110 kW: L _f = 1.5
(4) Load with an equivalent capacity of 110 to 300 KW: L _f = 1.2
(5) Load with an equivalent capacity of 300 KW or more: L _f = 1.0
[0053]
If there is no connection load, L _f = 1.0 may be adopted. However, if the load is unknown or simple calculation is acceptable, L _f = 1.0, but it is preferable to grasp the connection load capacity as much as possible.
[0054]
In addition, D in equation (2) _f Is a detector coefficient, which differs depending on whether the harmonic component contained in the device current is measured by a clamp-type current measurement or the magnetic flux generated by the device current is measured by a magnetic field such as a search coil. That is, the numerical value obtained by the magnetic field measurement is lower than the numerical value by the current measurement by the amount of spatial propagation attenuation of the magnetic flux. As a result of statistically comparing and analyzing the measured values of both the above-mentioned formulas, _f As a result, the following values were adopted. However, if the current fluctuation is severe, repeat the measurement several times and take the average.
(1) When using clamp current measurement: D _f = 1.6
(2) When measuring magnetic field such as search coil: D _f = 1.0
[0055]
Further, in the formula (2), Ma, Mb and Mc are equipment constants determined by whether the motor is operated independently or by the inverter operation, and have the following values, respectively.
(1) In case of single motor operation
M _a = 0.02, M _b = 0.01, M _c = 0
(2) Inverter operation
M _a = 0.2, M _b = 0.1, M _c = 1.0
[0056]
And K in equation (2) _V Is a voltage coefficient expressed by the following equation (6). In the equation (6), the numerical value X is 200 when the input voltage of the electric motor or the inverter is 200V system, 400 when the input voltage is 200V system and 3000V system. And 3000.
[0057]
[Equation 3]

[0058]
Also, K in equation (2) _h Is a harmonic countermeasure coefficient during inverter operation and takes the following values.
(1) K if there is no harmonic countermeasure _h = 1
(2) If there is a countermeasure against harmonics, the average will be as follows, although it depends on the countermeasure component. However, the numerical values are for the fifth and seventh harmonics, and in the case of the eleventh and higher harmonics and other harmonics, the numerical values are in parentheses.
a. K when installing line filter _h = 0.90 (0.95)
b. K when installing AC reactor _h = 0.60 (0.85)
c. K when installing a DC reactor _h = 0.55 (0.95)
d. K when installed with AC + DC reactor _h = 0.40 (0.90)
e. K when installing EMI filter _h = 0.60 (0.80)
[0059]
Note that K in equation (2) _S Is the power impedance Z (%), K _W Is a load factor (%), and the numerical values used in the calculation are values divided by 100 respectively.
[0060]
By the way, in the inverter operation, the sixth harmonic component should be taken into consideration, although it is not expressed in the equation (2). This sixth-order harmonic component is caused by the bearing or coupling on the rotating shaft of the motor even a little when the inverter operating frequency is ½ of the power supply frequency, that is, when the commercial power supply frequency is 60 Hz. If there is an imbalance, the sixth harmonic content may reach 1 / n (n is the harmonic order), that is, about 16%. In this case, since the content of other order harmonics also tends to increase, care must be taken to satisfy the following equation when performing inverter operation.
Inverter operating frequency ≠ (commercial power supply frequency) / m (integer)
[0061]
Thus, the harmonic current on the input side is obtained, and the harmonic content of each order can be calculated. Here, speaking only from the viewpoint of abnormality / deterioration diagnosis of the electric motor and the inverter as the electric equipment, it is sufficient to consider the harmonic order on the input side of the electric equipment up to the tenth order, which will be described later.
[0062]
Next, returning to FIG. 2, the output current of the inverter 53, that is, the motor current I flowing through the motor 52. _n2 As a result of the inventor accumulating a lot of data and performing statistical analysis, it has been found that the present invention can be expressed by the following equation.
[0063]
[Expression 4]

Where I ₁₂ : Fundamental current of motor current, n: harmonic order
h: Harmonic coefficient, K _m : Electric motor constant
[0064]
Km in the equation (7) is the following numerical value.
(1) Km = 0.05 (however, n = 2)
(2) Km = 0.15 (where n = 3)
(3) Km = 1.0 (except n = 2, 3)
The reason why Km differs only in the above (1) and (2) is that the voltage and current waveforms originally supplied by the three-phase AC power source are both symmetric waves, so that n = 2 and its integral multiple harmonics are It does not occur and Km = 0. Further, when the voltage and current of the three-phase AC power supply are balanced and the unbalance rate is zero, n = 3 and its integral multiple harmonics are not generated, and Km = 0. However, in reality, Km ≠ 0 due to the influence of other electric equipment (for example, an inverter) and an induction electromagnetic field.
[0065]
Further, the harmonic coefficient h in the equation (7) has different values depending on the following three harmonic order (n) regions.
(1) If 5> n, h = 2
(2) h = 1 when 11> n ≧ 5
(3) When n ≧ 11, h = 1.6
[0066]
As described above, the harmonic current on the inverter output side is obtained. Here, if the inverter is a voltage type inverter such as a sine wave PWM control system, the output impedance is small, and since it acts as a voltage source for the motor as a load, it is included in the output side current. Harmonic content is small. In the formula (7), K _V , K _S And K _W Has the same meaning as that expressed by equation (2), but if the inverter is considered a voltage source, K _S = 0. However, in the case of current source inverter, K _S = 1 and the inverter coefficient C in equation (7) _S Multiply (not described). At this time C _S The present inventor has confirmed that if the calculation is performed with = 2, the result is almost in line with the actual situation.
[0067]
In addition, the voltage coefficient K _V Is expressed by equation (6), X in equation (6) can be considered as a voltage proportional to the operating frequency. Therefore, for example, in the case of a 200 V system with a commercial power frequency of 60 Hz and a 30 Hz operation, the output voltage is 100 V, and the voltage coefficient K _V Is about 1.4.
[0068]
As described above, the calculation method of the harmonic current of each order flowing in the device current according to the present invention has been described. The abnormality / deterioration determination value of the electric device based on the calculation result will be described in an example described later.
[0069]
By the way, as described above, in order to precisely specify the degree of abnormality and deterioration of an electrical device, the cause and location of the abnormality / degradation, the current of each phase (R phase, S phase, T phase) of the electrical device Measure the rms value. This current measurement is preferable because a clamp-type ammeter can be performed without contact. From each phase current obtained from the measurement, the current unbalance rate is obtained by the following equation.
Current imbalance ratio = {(Imax−Imin) / Imin} × 100 (%) (8)
Here, Imax and Imin are the maximum value and the minimum value of each phase current, respectively.
[0070]
【Example】
As an example of the present invention, motor / inverter abnormality / deterioration judgment values are classified into “normal”, “caution” and “bad” based on these judgment values, and the cause of abnormality / degradation and location are identified. The explanation is as follows. In addition, the numerical value of the harmonic content about "normal", "attention required", and "defect" of the abnormality / deterioration determination value of the present invention is not limited to the example.
[0071]
In the judgment value classification, “normal” is described as A level, “caution” is described as B level, and “bad” is described as C level. Mild deterioration (deterioration that does not hinder driving for about 1 year) is B1 (rank), moderate deterioration (deterioration that does not hinder driving for about 6 months but requires trend management) is B2 (rank ), Severe degradation (deterioration that can be operated for about 3 months, but there is concern about equipment troubles and parts need to be replaced or repaired) is divided into 3 ranks (B3) Yes.
[0072]
Table 4 shows an abnormality / degradation criteria table for electrical equipment. The calculated value at the time of the harmonic diagnosis in the motor input in the table is a value obtained by the equation (2) or (7), but it is easy and convenient to obtain by the equation (7) in the case of motor independent operation. . In addition, the calculated values at the input and output of the harmonic diagnosis when the inverter is used are obtained by the equations (2) and (7), respectively. Further, when the apparatus according to the present invention is a precision type, it is necessary to perform a current diagnosis as shown in Table 4, but when it is a simple type, only a harmonic diagnosis is required.
[0073]
[Table 4]

[0074]
Table 5 is an electric motor diagnosis determination table calculated based on the determination criteria of Table 4. In Table 5, the calculated value used as a criterion for “normal” determination used for harmonic diagnosis is the power load coefficient L _f = 1.0, detector coefficient D _f = 1.0 (using a non-contact magnetic field detector with a search coil). A clamp type sensor was used for current diagnosis.
[0075]
[Table 5]

[0076]
Table 6 is a specific table of causes and locations of motor deterioration. This table shows the relationship between the harmonic order and the cause and location of the motor deterioration. It became clear for the first time by statistical analysis based on accumulated data and probabilistic analysis based on experimental data. Is. In particular, it is one of the great achievements of the present invention that it has been clarified that the second to fifth harmonics are deterioration due to the electric motor, and the seventh to tenth harmonics are due to the load.
[0077]
[Table 6]

[0078]
Table 7 is a specific table of causes and locations of deterioration of motors and inverters. This table shows the relationship between the harmonic order during motor operation by inverter control and the cause / location of motor / inverter deterioration. As in Table 6, technical know-how was systematized using experimental analysis techniques. Is.
[0079]
[Table 7]

[0080]
【The invention's effect】
The apparatus for diagnosing abnormality and deterioration of electrical equipment according to the present invention is intended for electric motors and inverters, and has the following effects.
[0081]
(1) Since the non-contact measuring instrument of the present invention has a simple, simple and inexpensive circuit configuration, it is possible to diagnose abnormalities and deterioration of electrical equipment for motors and inverters without requiring a specialist engineer. It can be done safely.
(2) In addition to the diagnosis of deterioration of electrical equipment in question, it is also used for inspection of power equipment machinery, transportation defined by laws and regulations such as railway vehicles and elevators, and periodic inspection of transportation equipment .
(3) Theoretical equations can be derived based on statistical analysis based on accumulation of abnormal and deterioration data of electrical equipment over many years and probability analysis based on experimental data, and the apparatus of the present invention has been verified and confirmed on many equipment. Therefore, it is possible to make it ISO standard or JIS standard.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an electrical equipment abnormality and deterioration diagnosis apparatus.
FIG. 2 is a block diagram related to an inverter.
[Explanation of symbols]
1 Current detector
2 Magnetic field detector
10 Signal processing means
20 arithmetic processing means
21 Central processing unit (CPU)
22 Main memory circuit
23 Auxiliary memory circuit
24 Input port
25 Output port
30 Operating means
31 Display means
51 Three-phase AC power supply
52 Electric motor
53 Inverter
54 Converter section
55 Smoothing capacitor
56 Inverter section
57 Control section

Claims (2)

A current detection unit for measuring a device current flowing in the electric device, a magnetic field detection unit for detecting a magnetic flux generated by the device current, and a switch for selecting and switching between the magnetic field detection unit and the current detection unit, Each order obtained by calculating a harmonic component included in the device current by a signal processing means for performing input processing on the output from the switch and an arithmetic processing means for calculating the signal obtained by the signal processing means. From the harmonic content of the above, the degree of abnormality and deterioration of the electrical equipment, the cause of the abnormality and deterioration and the location of the display to specify the outside, the content items displayed by the display means from the outside An apparatus for diagnosing abnormalities and deterioration of electrical equipment, characterized by comprising operating means for changing the conditions and setting conditions. The apparatus for diagnosing abnormality and deterioration of an electric device according to claim 1, wherein the electric device is an induction motor and an inverter.

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