JP3452709B2 - Moving magnetic field generator - Google Patents
Moving magnetic field generatorInfo
- Publication number
- JP3452709B2 JP3452709B2 JP28624195A JP28624195A JP3452709B2 JP 3452709 B2 JP3452709 B2 JP 3452709B2 JP 28624195 A JP28624195 A JP 28624195A JP 28624195 A JP28624195 A JP 28624195A JP 3452709 B2 JP3452709 B2 JP 3452709B2
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- Prior art keywords
- phase
- frequency
- voltage
- power supply
- magnetic field
- Prior art date
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Description
【発明の詳細な説明】
【0001】
【発明の属する技術分野】本発明は、移動磁界発生装置
に関し、特に、これに限定する意図ではないが導電体,
磁性体あるいは永久磁石を回転駆動又はリニア駆動する
移動磁界発生装置に関する。
【0002】
【従来の技術】例えばビレットの連続鋳造では、タンデ
イッシュより鋳型に溶鋼が注入され、鋳型において溶鋼
は鋳型壁面から次第に冷却されつつ引き抜かれる。同一
高さの鋳型壁面における温度が不均一であると、表面割
れやシェル破断を生じ易い。これを改善するために、従
来は、円筒型の移動磁界発生装置(コア+電気コイル)
で鋳型を取り囲み、鋳型内溶鋼に一定方向の電磁駆動力
(回転推力)を与えて溶鋼を積極的に流動駆動している
(特開平2182358号公報)。鋳型内溶鋼に与える推力は電
気コイルに通電する電流値により調整することができ
る。
【0003】ところで、例えば鋳型が四角筒体であると
き、一定方向に溶鋼を駆動した場合に鋳型の角部におい
て溶鋼の滞留が起り易い。鋳型内面の一部に溶鋼が滞留
するとパウダが溶鋼に残留し易くしかもブレークアウト
の原因となる焼付きを生じ易い。これらを防止するた
め、移動磁界発生装置で溶鋼の撹拌を行うビレットの連
続鋳造では、溶鋼に与える回転推力に一層のたわみ性を
もたせて効率的に溶鋼を撹拌することが要求される。
【0004】そこで、低周波成分と高周波成分とを重畳
した合成波を生成し、この合波波を増幅して電気コイル
に通電することが提案されている。電気コイルが生成す
る磁界も該合成波に相似の強度変化を示し、低周波成分
と高周波成分を含む。低周波成分は溶鋼への浸透性が高
いので、内部の溶鋼を撹拌する作用が高い。高周波成分
は溶鋼への浸透性が低いので、表層の溶鋼を撹拌する作
用が高い。移動磁界を発生するための、電気コイルへの
通電の相切換えに関して、低周波成分と高周波成分の相
順を逆にすることにより、電流の低周波成分により現わ
れる低周波移動磁界と高周波成分により現われる高周波
移動磁界の方向が逆となり、溶鋼の表層と内部で逆向き
に溶鋼が流動し、溶鋼の円滑な撹拌効果が高い。
【0005】
【発明が解決しようとする課題】しかし、電気コイルに
低周波成分と高周波成分とを重畳した合成波を通電する
電源回路は、広帯域の周波数特性が必要でありしかも歪
波である合成波を形成するスイッチング回路が複雑なも
のとなって、設計が複雑になり高価であり、装置全体と
してコスト高となる。また、低周波成分と高周波成分そ
れぞれのレベル調整すなわち低周波移動磁界と高周波移
動磁界の個別のレベル調整がむつかしい。
【0006】本発明は、低周波移動磁界と高周波移動磁
界を同時に発生するための電源回路を簡単な構成にする
ことを第1の目的とし、低周波移動磁界と高周波移動磁
界の個別のレベル調整を容易にすることを第2の目的と
する。
【0007】
【課題を解決するための手段】本発明の移動磁界発生装
置は、コア(5)および該コアの延びる方向に分布する複
数個の電気コイル(C1〜C24)を有する電磁石(1);前記複
数個の電気コイルの第1グル−プのもの(C1,C2,C5,C6,C
9,C10,C13,C14,C17,C18,C21,C22)に、前記方向に移動す
る磁界を発生するための位相差がある、第1周波数(10H
z)の交流電圧を印加する第1通電手段(20A);および、
前記複数個の電気コイルの第2グル−プのもの(C3,C4,C
7,C8,C11,C12,C15,C16,C19,C20,C23,C24)に、前記方向
に移動する磁界を発生するための位相差がある、第1周
波数とは異なる第2周波数(5Hz)の交流電圧を印加する
第2通電手段(20B);を備え、該第2通電手段(20B)が、
電気コイルの並び方向に関して、第1通電手段(20A)が
第1グル−プの電気コイルに加える交流電圧の相順と逆
の相順で第2グル−プの電気コイルに交流電圧を印加す
ることを特徴とする。なお、理解を容易にするためにカ
ッコ内には、図面に示し後述する実施例の対応要素又は
対応事項に付した記号を、参考までに付記した。
【0008】これによれば、第1グル−プの電気コイル
により第1周波数(10Hz)の移動磁界が生成され、第2グ
ル−プの電気コイルにより第2周波数(5Hz)の移動磁界
が生成される。第1通電手段(20A)は、第1周波数(10H
z)に合った周波数特性のサイン波交流電圧を発生するも
のであればよく、構成は簡単で設計が容易である。ま
た、第2通電手段(20B)も、第2周波数(5Hz)に合った周
波数特性のサイン波交流電圧を発生するものであればよ
く、構成は簡単で設計が容易である。加えて、第1通電
手段(20A)および第2通電手段(20B)で個別に第1グル−
プおよび第2グル−プの電気コイルの通電レベル、つま
りは第1周波数および第2周波数の移動磁界の強度、を
個別に調整することができ、この調整は簡単である。
【0009】さらには、第2通電手段(20B)は、電気コ
イルの並び方向に関して、第1通電手段(20A)が第1グ
ル−プの電気コイルに加える交流電圧の相順と逆の相順
で第2グル−プの電気コイルに交流電圧を印加する。こ
れにより、第1周波数と第2周波数の移動磁界の方向が
互に逆向きとなる。
【0010】本発明の移動磁界発生装置を鋳型内溶鋼の
水平回転駆動に用いる場合には、上記のように第1グル
−プの電気コイルに加える交流電圧の相順と逆の相順で
第2グル−プの電気コイルに交流電圧を印加することに
より、溶鋼の、鋳型内壁面に接する溶鋼表層部に第1周
波数の移動磁界による例えば時計方向の回転推力が作用
し、溶鋼内部には第2周波数の移動磁界による反時計方
向の回転推力が作用し、円滑な溶鋼撹拌が実現する。
【0011】本発明の移動磁界発生装置の電磁石(1)の
コア(5)をリング状のものとすることにより、本発明の
移動磁界発生装置は回転磁界発生装置となり、コア(5)
を直方体状のものとすることにより、本発明の移動磁界
発生装置はリニアモ−タ型の移動磁界発生装置となる。
いずれも、鋳型内溶鋼の駆動に用い得るのは勿論、電気
モ−タのステ−タとして用いることができる。電気モ−
タのステ−タとして用いる場合、例えば、ロ−タを2重
筒状にして、外側ロ−タと内側ロ−タを個別に回転駆動
することができ、上記のように第1グル−プの電気コイ
ルに加える交流電圧の相順と逆の相順で第2グル−プの
電気コイルに交流電圧を印加すると、外側ロ−タと内側
ロ−タを逆方向に回転駆動することができる。このよう
な電気モ−タを、リング状コアを1個所で切断して直方
体状に延ばす形に、ステ−タおよびロ−タをリニアモ−
タ型のものに変更することにより、リニアモ−タでも同
様な駆動(上述の回転駆動を直線駆動にしたもの)を行
なうことができる。
【0012】本発明の他の目的および特徴は、図面を参
照した以下の実施例の説明より明らかになろう。
【0013】
【発明の実施の形態】
【実施例】図1に、本発明の一実施例の全体構成を示
し、図2には鋳型Mおよびリニアモータ1の横断面(図
1および図3の2A−2A線切断面)を示し、図3には
鋳型周りを拡大して示す。図中Mは、ビレット製造用の
小型の連続鋳造鋳型である。これに図示しない注入ノズ
ルを通して溶鋼MMが、図1紙面の表側から裏側に向け
て(垂直方向zで上方から下方に)、注入される。正方
形の鋳型Mを形成する各辺は銅板M2に、非磁性ステン
レス板M1を裏当てしたものである。
【0014】この実施例では、四角筒体である連続鋳造
鋳型Mを、円筒型の電磁石1が包囲しており、連続鋳造
鋳型Mの四方の外側面を電磁石1の略円筒状の電磁石コ
ア5の内周面が取り囲んでいる。電磁石コア5の内周面
に、放射状に外周面に向うスロットが周方向に24個、
等ピッチで形成されている。電磁石コア5は、内歯付平
板リング形の薄電磁鋼板を積層したものである。電磁石
コア5の外周縁には縦断面が「コ」の字型である略リン
グ型の巻芯4(本実施例においてはCu製)が装着され
ており、電気コイルC1〜C24が電磁石コア5の各ス
ロットに案内され、さらに巻芯4の外側面を巻き回され
て、コア5に「胴巻き」されている。(コイルNo.
は、図1において全No.を記載していないが、C1か
ら時計廻りに順にC24までである。)なお、電磁石コ
ア5,巻芯4および電気コイルC1〜C24は冷却され
かつ耐熱カバ−2(本実施例においてはSuS製)で被
覆されているが、耐熱カバ−2内部の空間3及び巻芯4
に設けられた冷却構造は図示を省略している。電磁石コ
ア5の各スロット間の歯が磁極でありその端面が、連続
鋳造鋳型Mの外側面に対向している。
【0015】各電気コイルC1〜C24の内、半数(第
1グル−プ)の電気コイルC1,C2,C5,C6,C
9,C10,C13,C14,C17,C18,C2
1,C22には、電源端子TUa〜TWaを介して高周
波(設計値:10Hz)の3相交流電圧を発生する高周
波電源回路20A(以下、電源回路20A)が接続され
るとともに、各電気コイルC1〜C24の内、残りの半
数(第2グル−プの電気コイルC3,C4,C7,C
8,C11,C12,C15,C16,C19,C2
0,C23,C24には電源端子TUb〜TWbを介し
て低周波(設計値:5Hz)の3相交流電圧を発生する
低周波電源回路20B(以下、電源回路20B)が接続
される。
【0016】電源回路20Aおよび電源回路20Bは、
制御回路Pに接続されている。制御回路Pは、外部より
入力される高周波指示値fhに対応した周波数指令値F
H及び指示電流値iAに対応したコイル電圧指令値Vdc
Aを電源回路20Aに与え、低周波指示値fLに対応し
た周波数指令値FL及び指示電流値iBに対応したコイ
ル電圧指令値VdcBを電源回路20Bに与える。電源回
路20Aは、周波数指令値FHで指示された高周波数の
3相交流電圧をコイル電圧指令値VdcAに対応した電圧
値で電源端子TUa〜TWaを介して電気コイルC1〜
C24の内、第1グル−プの電気コイルに与える。ま
た、電源回路20Bは、周波数指令値FLで指示された
低周波数の3相交流電圧をコイル電圧指令値VdcBに対
応した電圧値で電源端子TUb〜TWbを介して電気コ
イルC1〜C24の内、残りの第2グル−プの電気コイ
ルに与える。
【0017】この実施例では、鋳型M内の溶鋼MMを、
鋳型Mのxy面上における中心点を原点Oとすれば、鋳
型Mの鋳型辺に近い領域では各辺に沿った図1紙面上に
おいて点線矢印Faで示す時計回り方向に回転駆動し、
それよりさらに内側の原点Oに近い領域では図1紙面上
において1点鎖線矢印Fbで示す原点Oを中心とした反
時計回り方向に回転駆動する。以下に電磁石1の、結線
を含めた構成および溶鋼に与える作用を説明する。
【0018】図3には、鋳型Mおよび電磁石1の拡大横
断面(xy平面による切断面)及び全電気コイルの結線
を示す。電磁石1の電気コイルC1−2,C5−6,C
9−10の一端は高周波の3相交流電圧を発生する電源
回路20Aの電源接続端子TUa,TVa,TWaに接
続されており、他端はそれぞれ電気コイルC13−1
4,C17−18,C21−22に接続されている。ま
た、電磁石1の電気コイルC12−11,C16−1
5,C19−20は低周波の3相交流電圧を発生する電
源回路20Bの3相電源接続端子TVb,TUb,TW
bに接続されており、他端はそれぞれ電気コイルC23
−24,C3−4,C7−8に接続されている。
【0019】すなわち、電源回路20Aに接続されてい
る電気コイルと電源回路20Bに接続されている電気コ
イルが、電磁石コア5のスロットに2づつ交互に装着さ
れている。しかもその相配置は、電源回路20Aが与え
る高周波の3相交流電圧が、端子TUa,TVa,TW
aを介してそれに接続される前述の各電気コイルに、図
1,図3において時計回りにUa,Ua,va,va,
Wa,Wa,ua,ua,Va,Va,wa,waとさ
れているのに対し、電源回路20Bが与える低周波の3
相交流電圧が、端子TUb,TVb,TWbを介してそ
れに接続される前述の各電気コイルに、図1,図3にお
いて反時計回りにub,ub,Vb,Vb,wb,w
b,Ub,Ub,vb,vb,Wb,Wbとされてい
る。ここで、「Ua,Ub」は3相交流のU相の正相通
電(そのままの通電)を、「ua,ub」はU相の逆相
通電(U相より180度の位相づれ通電)を表し、「U
a,U」で表される電気コイルにはその巻始め端にU相
が印加されるのに対し、「ua,ub」で表される電気
コイルにはその巻終り端にU相が印加されることを意味
する。同様に、「Va,Vb」は3相交流のV相の正相
通電を、「va,vb」はV相の逆相通電を、「Wa,
Wb」は3相交流のW相の正相通電を、「wa,wb」
はW相の逆相通電を表わす。
【0020】電源回路20Aは、制御回路Pより出力さ
れるコイル電圧指令値VdcAにより3相交流電圧の電圧
レベルを決定し、周波数指令値FHにより3相交流電圧
の周波数を設定する。電源回路20Aは、こうして電圧
レベル,周波数が決定された3相交流電圧(Ua,V
a,Wa)をそれぞれ電源接続端子TUa,TVa,T
Waを介して電気コイルC1−2,C5−6,C9−1
0に印加する。
【0021】図4に、電気コイルC1−2,C5−6,
C9−10に高周波の3相交流を流す電源回路20Aの
構成を示す。3相交流電源(3相電力線)21には、直
流整流用のサイリスタブリッジ22Aが接続されてお
り、その出力(脈流)はインダクタ25Aおよびコンデ
ンサ26Aで平滑化される。平滑化された直流電圧は3
相交流形成用のパワ−トランジスタブリッジ27Aに印
加され、これが出力する3相交流のU相が図1および図
3に示す電源接続端子TUaに、V相が電源接続端子T
Vaに、またW相が電源接続端子TWaに印加される。
【0022】電気コイルC1−2,C5−6,C9−1
0が、連続鋳造鋳型M内部の溶鋼MMを回転駆動する推
力を発生するコイル電圧指令値VdcAが位相角α算出器
24Aに与えられ、位相角α算出器24Aが、指令値V
dcAに対応する導通位相角α(サイリスタトリガ−位相
角)を算出し、これを表わす信号をゲ−トドライバ23
Aに与える。ゲ−トドライバ23Aは、各相のサイリス
タを、各相のゼロクロス点から位相カウントを開始して
位相角αで導通トリガ−する。これにより、トランジス
タブリッジ27Aには、指令値VdcAが示す直流電圧が
印加される。
【0023】一方、3相信号発生器31Aは、周波数指
令値FHで指定された周波数の、定電圧3相交流信号
U,V,Wを発生して、比較器29Aに与える。比較器
29Aにはまた、三角波発生器30Aが6KHz前後
の、周波数指令値FHに比例する周波数の、定電圧三角
波を与える。比較器29Aは、U相信号が正レベルのと
きには、それが三角波発生器30Aが与える三角波のレ
ベル以上のとき高レベルH(トランジスタオン)で、三
角波のレベル未満のとき低レベルL(トランジスタオ
フ)の信号を、U相の正区間宛て(Ua相正電圧出力用
トランジスタ宛て)にゲ−トドライバ28Aに出力し、
U相信号が負レベルのときには、それが三角波発生器3
0Aが与える三角波のレベル以下のとき高レベルHで、
三角波のレベルを越えるとき低レベルLの信号を、U相
の負区間宛て(Ua相負電圧出力用トランジスタ宛て)
にゲ−トドライバ28Aに出力する。V相信号およびW
相信号に関しても同様である。ゲ−トドライバ28A
は、これら各相,正,負区間宛ての信号に対応してトラ
ンジスタブリッジ27Aの各トランジスタをオン,オフ
付勢する。
【0024】これにより、電源接続端子TUaには、3
相交流のUa相電圧が出力され、電源接続端子TVaに
同様なVa相電圧が出力され、また電源接続端子TWa
に同様なWa相電圧が出力され、これらの電圧の上ピ−
ク/下ピ−ク間レベルはコイル電圧指令値VdcAで定ま
る。この3相電圧の周波数はこの実施例では周波数指令
値FH(中心値が10Hz)により定まる。すなわち、
コイル電圧指令値VdcAで指定されたピ−ク電圧値(推
力)の、周波数がFH(例えば10Hz)の3相交流電圧
が、図1及び図3に示す電気コイルC1−2,C5−
6,C9−10に印加される。
【0025】電源回路20Bは、制御回路Pより出力さ
れるコイル電圧指令値VdcBにより3相交流電圧の電圧
レベルを決定し、周波数指令値FLにより3相交流電圧
の周波数を設定する。電源回路20Bは、こうして電圧
レベル,周波数が決定された3相交流電圧(Ub,V
b,Wb)をそれぞれ電源接続端子TVb,TUb,T
Wbを介して電気コイルC12−11,C16−15,
C19−20に印加する。
【0026】図5に、電気コイルC12−11,C16
−15,C19−20に低周波の3相交流を流す電源回
路20Bの構成を示す。電源回路20Bは、発生する周
波数(中心値が5Hz)が電源回路20Aに比べ低いの
で構成素子(部品)の周波数特性が低いのみで、システ
ム構成および動作は電源回路20Aと同様であるので詳
しい説明を省略する。最終的に、電源接続端子TUbに
は、3相交流のUb相電圧が出力され、電源接続端子T
Vbに同様なVb相電圧が出力され、また電源接続端子
TWbに同様なWb相電圧が出力される。なお、これら
の電圧の上ピ−ク/下ピ−ク間レベルはコイル電圧指令
値VdcBで定まり、この3相電圧の周波数はこの実施例
では周波数指令値FLにより定まる。すなわち、コイル
電圧指令値VdcBで指定されたピ−ク電圧値(推力)
の、周波数がFL(例えば5Hz)の3相交流電圧が、図
1及び図3に示す電気コイルC12−11,C16−1
5,C19−20に印加される。
【0027】図6は、電磁石1が溶鋼MMに与える電磁
力分布を、電源回路20Aによるもの(点線)と電源回
路20Bによるもの(1点鎖線)に分解して表し、さら
に、それらの合力による電磁力分布(実線)を表したグ
ラフである。グラフ中、縦軸は溶鋼MM中の電磁力の大
きさを示しており、原点Oより上向き矢印方向が図1紙
面対応の時計回り方向であり、その逆が図1紙面対応の
反時計回り方向である。また、横軸は鋳型Mの原点Oか
らのx方向距離を示しており、σが鋳型Mの内壁面位置
を示している。グラフを参照すると、電源回路20Aは
時計廻り方向の移動磁界(これによる推力)を溶鋼MM
に与えるのに対し、電源回路20Bは、反時計廻り方向
の移動磁界(推力)を溶鋼MMに与えている。そして、
3相交流電圧の周波数が異る2つの電源回路20A,2
0Bが与える推力の差し引きは、図1,図6に示すよう
に、鋳型M内の溶鋼MMを、鋳型Mの鋳型辺に近い領域
では各辺に沿った図1紙面上において点線矢印Faで示
す時計回り方向に回転駆動し、それよりさらに内側の原
点Oに近い領域では図1紙面上において1点鎖線矢印F
bで示す原点Oを中心とした反時計回り方向に回転駆動
する。
【0028】本実施例によれば、鋳型M内の溶鋼MMは
鋳型Mの中央部(原点O付近)と鋳型辺付近とでは異る
方向に撹拌されるので、同方向に撹拌する場合に比べて
撹拌効率が向上し、鋳型内面がぬぐわれ、気泡の浮上が
促される。すなわち、製品の品質が向上するとともに、
焼き付きが防止される。
【0029】さらに本実施例では、高価で大容量である
広周波数帯域の3相交流電源を用いずに、高周波電源回
路20Aと低周波電源回路20B、計2つの3相交流電
源が周波数に応じて3相交流電圧を印加する電気コイル
を分担している。狭周波数帯域の3相交流電源は、広周
波数帯域の3相交流電源に比べて設計が容易である上に
構成素子が安価である。しかも、各電源回路20A,2
0Bは、サイン波電圧を出力するものであるので回路構
成が簡素であり、低コストの3相交流電源を用いた流動
制御装置となる。
【0030】高周波磁界は、溶鋼MMに対する浸透性が
低く、高周波磁束はコア5の表面、特にエッジ部に集中
する傾向を示す。これにより誘起される渦電流が、コア
5のスロット間の歯先端,スロット底、および、外周面
エッジに局所的な高温度上昇をもたらす。そこで上述の
実施例では、図2および図3に示すように、高周波が通
電される第1グル−プの電気コイルの近辺の、スロット
間の歯先端,スロット底、および、外周面エッジに、半
径方向に延びる、歯端スリットGs,スロット底スリッ
トSs、および、背面スリットBsを刻んで、渦電流を
遮断するようにした。これらのスリットは、図2に示す
ように、コア5の各エッジ部にあるので、それぞれ周方
向の1箇所で1対となっている。これにより、局所的な
温度上昇が低下した。
【0031】なお、本実施例においては電源回路20A
と電源回路20Bがそれぞれ各電気コイルに与える3相
交流電圧の方向が、第1グループのものと第2グループ
のものとで異っている。しかし、電磁石1の各電気コイ
ルに与えられる3相交流電圧の方向は、同方向で周波数
のみを変えてもよい。この場合、第1グループの電気コ
イルと第2グループの電気コイルの結線を全く同じと
し、その他の構成は前述の実施例の構成と同じである。
これによれば、鋳型Mの鋳型辺に近い領域とそれよりさ
らに内側の原点Oに近い領域とでは、同方向で大きさの
異る推力が発生する。溶鋼MMは、鋳型Mの鋳型辺に近
い領域とそれよりさらに内側の原点Oに近い領域とで
は、同方向にしかし異る流速で回転駆動される。すなわ
ち、原点Oに近い領域の溶鋼MMの流速を調節できる。
これにより前述の実施例と同様の効果がある。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving magnetic field generator, and more particularly to, but not limited to, a conductor,
The present invention relates to a moving magnetic field generating device that rotationally or linearly drives a magnetic body or a permanent magnet. 2. Description of the Related Art In continuous casting of billets, for example, molten steel is poured into a mold from a tundish, and in the mold, the molten steel is drawn out while being gradually cooled from the wall of the mold. If the temperatures on the mold wall surfaces at the same height are not uniform, surface cracks and shell ruptures are likely to occur. Conventionally, to improve this, a cylindrical moving magnetic field generator (core + electric coil)
The electromagnetic force (rotational thrust) in a certain direction is applied to the molten steel in the mold to positively drive the molten steel (Japanese Patent Laid-Open No. 2182358). The thrust given to the molten steel in the mold can be adjusted by the value of the current supplied to the electric coil. By the way, when the molten steel is driven in a certain direction, for example, when the molten steel is driven in a certain direction, the molten steel tends to stay at the corners of the molten metal. If the molten steel stays in a part of the inner surface of the mold, the powder tends to remain in the molten steel and seizure which causes a breakout easily occurs. In order to prevent these problems, in continuous casting of billets in which molten steel is agitated by a moving magnetic field generator, it is required that the molten steel be efficiently agitated by imparting more flexibility to the rotational thrust applied to the molten steel. Therefore, it has been proposed to generate a composite wave in which a low-frequency component and a high-frequency component are superimposed, amplify the combined wave, and energize an electric coil. The magnetic field generated by the electric coil also exhibits a change in intensity similar to the composite wave, and includes a low frequency component and a high frequency component. Since the low frequency component has high permeability to the molten steel, it has a high effect of stirring the molten steel inside. Since the high-frequency component has low permeability to the molten steel, it has a high effect of stirring the molten steel on the surface layer. With respect to the phase switching of energization to the electric coil for generating the moving magnetic field, the phase order of the low frequency component and the high frequency component is reversed, so that the low frequency component and the high frequency component appear by the low frequency component of the current. The direction of the high-frequency moving magnetic field is reversed, and the molten steel flows in the opposite direction between the surface layer and the inside of the molten steel, and the effect of smoothly stirring the molten steel is high. [0005] However, a power supply circuit that supplies a synthetic wave in which a low-frequency component and a high-frequency component are superimposed on an electric coil requires a wide-band frequency characteristic and is a distorted wave. The switching circuit for forming the waves becomes complicated, the design becomes complicated and expensive, and the cost of the whole device becomes high. Further, it is difficult to adjust the levels of the low-frequency component and the high-frequency component, that is, to individually adjust the levels of the low-frequency moving magnetic field and the high-frequency moving magnetic field. SUMMARY OF THE INVENTION It is a first object of the present invention to simplify a power supply circuit for simultaneously generating a low-frequency moving magnetic field and a high-frequency moving magnetic field, and to individually adjust the levels of the low-frequency moving magnetic field and the high-frequency moving magnetic field. A second object is to facilitate the following. [0007] According to one aspect of the present onset Ming traveling magnetic field generating device, an electromagnet (1 having a core (5) and a plurality of electrical coils distributed in the extending direction of the core (C1 to C24) ); The plurality of electric coils of the first group (C1, C2, C5, C6, C
9, C10, C13, C14, C17, C18, C21, C22), there is a phase difference for generating a magnetic field moving in the direction, the first frequency (10H
first energizing means (20A) for applying the AC voltage of z); and
The second group of the plurality of electric coils (C3, C4, C3)
7, C8, C11, C12, C15, C16, C19, C20, C23, C24), there is a phase difference for generating a magnetic field moving in the direction, a second frequency (5 Hz) different from the first frequency second energizing means for applying the AC voltage (20B); with a second conductive member (20B) is,
Regarding the arrangement direction of the electric coils, the first energizing means (20A)
Reverse phase sequence of AC voltage applied to electric coil of first group
AC voltage is applied to the electric coil of the second group in the order of
It characterized the Rukoto. In addition, in order to facilitate understanding, in parentheses, symbols attached to corresponding elements or corresponding items of the embodiment shown in the drawings and described later are added for reference. According to this, the moving magnetic field of the first frequency (10 Hz) is generated by the electric coil of the first group, and the moving magnetic field of the second frequency (5 Hz) is generated by the electric coil of the second group. Is done. The first energizing means (20A) is connected to the first frequency (10H
What is necessary is just to generate a sine wave AC voltage having a frequency characteristic suitable for z), and the configuration is simple and the design is easy. Also, the second energizing means (20B) may be any as long as it generates a sine wave AC voltage having a frequency characteristic matching the second frequency (5 Hz), and the configuration is simple and the design is easy. In addition, the first energizing means (20A) and the second energizing means (20B) individually form the first group.
The energization level of the electric coils of the loop and the second group, that is, the strength of the moving magnetic field of the first frequency and the second frequency can be individually adjusted, and this adjustment is simple. Further, the second energizing means (20B) has a phase sequence opposite to that of the AC voltage applied to the electric coils of the first group by the first energizing means (20A) with respect to the arrangement direction of the electric coils. To apply an AC voltage to the electric coil of the second group. More this, the direction of the first frequency and the moving magnetic field of the second frequency is mutually opposite. When the moving magnetic field generator of the present invention is used for horizontal rotation drive of molten steel in a mold , the first group
-The phase sequence of the AC voltage applied to the
By applying an AC voltage to the electric coil of the second group, a rotating thrust, for example, clockwise in the molten steel is applied to the surface of the molten steel in contact with the inner wall surface of the mold by the moving magnetic field of the first frequency. A counterclockwise rotating thrust by the moving magnetic field of the second frequency acts, and smooth molten steel stirring is realized. By making the core (5) of the electromagnet (1) of the moving magnetic field generator of the present invention ring-shaped, the moving magnetic field generator of the present invention becomes a rotating magnetic field generator, and the core (5)
Is a rectangular parallelepiped, the moving magnetic field generator of the present invention becomes a linear motor type moving magnetic field generator.
Either of these can be used not only for driving molten steel in a mold, but also as a stator for an electric motor. Electric motor
When used as a motor, for example, Russia - - Other stearate and the data double cylindrical shape, the outer Russia - motor and the inner Russia - data to be able to drive individually rotated, the first glue as described above - flop Electric carp
Of the second group in a phase sequence opposite to that of the AC voltage applied to the
When an AC voltage is applied to the electric coil , the outer rotor and the inner rotor can be driven to rotate in opposite directions. In such an electric motor, a stator and a rotor are linear motors in such a shape that a ring-shaped core is cut at one place and extended in a rectangular parallelepiped shape.
By changing to a linear motor, a similar drive (in which the above-described rotary drive is linearly driven) can be performed by a linear motor. Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings. FIG. 1 shows an overall configuration of an embodiment of the present invention. FIG. 2 shows a cross section of a mold M and a linear motor 1 (see FIG. 1 and FIG. 3). 2A-2A line), and FIG. 3 shows an enlarged view of the periphery of the mold. In the figure, M is a small continuous casting mold for billet production. Molten steel MM is injected through an injection nozzle (not shown) from the front side to the back side in FIG. 1 (from above in the vertical direction z to below). Each side forming the square mold M is obtained by backing a non-magnetic stainless steel plate M1 to a copper plate M2. In this embodiment, a cylindrical electromagnet 1 surrounds a continuous casting mold M, which is a quadrangular cylindrical body, and a substantially cylindrical electromagnet core 5 of the electromagnet 1 covers the four outer surfaces of the continuous casting mold M. Is surrounded by an inner peripheral surface. On the inner peripheral surface of the electromagnet core 5, there are 24 slots radially toward the outer peripheral surface in the circumferential direction,
They are formed at an equal pitch. The electromagnet core 5 is formed by laminating thin electromagnetic steel plates of a flat ring shape with internal teeth. A substantially ring-shaped core 4 (in this embodiment, made of Cu) having a U-shaped vertical section is attached to the outer peripheral edge of the electromagnet core 5, and the electric coils C1 to C24 are connected to the electromagnet core 5. , And further wound around the outer surface of the winding core 4, and “wound around” the core 5. (Coil No.
Are all Nos. In FIG. , But from C1 to C24 in a clockwise order. The electromagnet core 5, the winding core 4, and the electric coils C1 to C24 are cooled and covered with a heat-resistant cover-2 (made of SuS in this embodiment). Core 4
Are not shown in the figure. The teeth between the slots of the electromagnet core 5 are magnetic poles, and their end faces face the outer side of the continuous casting mold M. Half of the electric coils C1, C2, C5, C6, C (half of the first group) among the electric coils C1 to C24.
9, C10, C13, C14, C17, C18, C2
1 and C22, a high-frequency power supply circuit 20A (hereinafter, power supply circuit 20A) that generates a high-frequency (design value: 10 Hz) three-phase AC voltage via power supply terminals TUa to TWa is connected, and each electric coil C1 To C24 (the remaining half of the electric coils C3, C4, C7, C2 of the second group).
8, C11, C12, C15, C16, C19, C2
A low-frequency power supply circuit 20B (hereinafter, power supply circuit 20B) that generates a low-frequency (design value: 5 Hz) three-phase AC voltage is connected to 0, C23, and C24 via power supply terminals TUb to TWb. The power supply circuit 20A and the power supply circuit 20B
It is connected to the control circuit P. The control circuit P has a frequency command value F corresponding to the high frequency command value fh input from the outside.
H and the coil voltage command value Vdc corresponding to the command current value iA
A is supplied to the power supply circuit 20A, and the frequency command value FL corresponding to the low frequency command value fL and the coil voltage command value VdcB corresponding to the command current value iB are provided to the power supply circuit 20B. The power supply circuit 20A converts the high-frequency three-phase AC voltage designated by the frequency command value FH to a voltage value corresponding to the coil voltage command value VdcA via the power supply terminals TUa to TWa via the electric coils C1 to TWa.
C24 is given to the first group of electric coils. Further, the power supply circuit 20B converts the low-frequency three-phase AC voltage designated by the frequency command value FL to a voltage value corresponding to the coil voltage command value VdcB via the power supply terminals TUb to TWb among the electric coils C1 to C24. The remaining second group of electric coils is fed. In this embodiment, molten steel MM in mold M is
Assuming that the center point on the xy plane of the mold M is the origin O, in a region close to the mold sides of the mold M, it is rotationally driven in a clockwise direction indicated by a dotted arrow Fa on the paper surface of FIG.
In a region closer to the origin O which is further inside, it is driven to rotate counterclockwise around the origin O indicated by a dashed-dotted arrow Fb on the plane of FIG. Hereinafter, the configuration including the connection of the electromagnet 1 and the effect on the molten steel will be described. FIG. 3 shows an enlarged cross section (cut plane by the xy plane) of the mold M and the electromagnet 1 and connection of all electric coils. Electric coil C1-2, C5-6, C of electromagnet 1
One end of 9-10 is connected to power supply connection terminals TUa, TVa, TWa of a power supply circuit 20A that generates a high-frequency three-phase AC voltage, and the other end is an electric coil C13-1.
4, C17-18, C21-22. Also, the electric coils C12-11 and C16-1 of the electromagnet 1
5, C19-20 are three-phase power connection terminals TVb, TUb, TW of a power circuit 20B for generating a low-frequency three-phase AC voltage.
b and the other end is connected to an electric coil C23, respectively.
-24, C3-4, C7-8. That is, two electric coils connected to the power supply circuit 20A and two electric coils connected to the power supply circuit 20B are alternately mounted in the slots of the electromagnet core 5. Moreover, the phase arrangement is such that the high-frequency three-phase AC voltage provided by the power supply circuit 20A is applied to the terminals TUa, TVa, TW
a, Ua, Ua, va, va, clockwise in FIG. 1 and FIG.
Wa, Wa, ua, ua, Va, Va, wa, wa, whereas low-frequency 3 provided by the power supply circuit 20B.
The phase alternating voltage is applied counterclockwise in FIGS. 1 and 3 to ub, ub, Vb, Vb, wb, w in each of the aforementioned electric coils connected thereto via terminals TUb, TVb, TWb.
b, Ub, Ub, vb, vb, Wb, Wb. Here, “Ua, Ub” indicates the U-phase positive-phase energization of three-phase alternating current (energization as it is), and “ua, ub” indicates the U-phase reverse-phase energization (180 ° phase shift energization from the U-phase). And "U
The U-phase is applied to the electric coil represented by “a, U” at the beginning of its winding, whereas the U-phase is applied to the electric coil represented by “ua, ub” at the end of its winding. Means that Similarly, “Va, Vb” indicates V-phase positive-phase energization of three-phase AC, “va, vb” indicates V-phase negative-phase energization, and “Wa, Vb”.
"Wb" indicates the W-phase positive-phase energization of three-phase AC, and "wa, wb"
Represents reverse phase energization of the W phase. The power supply circuit 20A determines the voltage level of the three-phase AC voltage based on the coil voltage command value VdcA output from the control circuit P, and sets the frequency of the three-phase AC voltage based on the frequency command value FH. The power supply circuit 20A outputs the three-phase AC voltage (Ua, V
a, Wa) to the power supply connection terminals TUa, TVa, T
Electric coils C1-2, C5-6, C9-1 via Wa
Apply to 0. FIG. 4 shows electric coils C1-2, C5-6.
The configuration of a power supply circuit 20A for supplying a high-frequency three-phase alternating current to C9-10 is shown. A thyristor bridge 22A for DC rectification is connected to the three-phase AC power supply (three-phase power line) 21, and its output (pulsating flow) is smoothed by an inductor 25A and a capacitor 26A. The smoothed DC voltage is 3
The U-phase of the three-phase alternating current which is applied to the power-transistor bridge 27A for forming the phase alternating current and output from the power-transistor bridge 27A is connected to the power connection terminal TUa shown in FIGS.
Va and the W phase are applied to the power supply connection terminal TWa. Electric coils C1-2, C5-6, C9-1
0, a coil voltage command value VdcA for generating a thrust for rotationally driving the molten steel MM inside the continuous casting mold M is given to the phase angle α calculator 24A, and the phase angle α calculator 24A
A conduction phase angle α (thyristor trigger-phase angle) corresponding to dcA is calculated, and a signal representing this is calculated by the gate driver 23.
Give to A. The gate driver 23A starts the phase count of the thyristor of each phase from the zero cross point of each phase and triggers conduction at the phase angle α. As a result, the DC voltage indicated by the command value VdcA is applied to the transistor bridge 27A. On the other hand, the three-phase signal generator 31A generates constant-voltage three-phase AC signals U, V, and W having a frequency specified by the frequency command value FH, and supplies the generated signals to the comparator 29A. The comparator 29A also supplies a constant voltage triangular wave having a frequency of about 6 KHz, which is proportional to the frequency command value FH, by the triangular wave generator 30A. When the U-phase signal is at a positive level, the comparator 29A is at a high level H (transistor on) when the signal is equal to or higher than the level of the triangular wave provided by the triangular wave generator 30A, and is at a low level L (transistor off) when the signal is lower than the triangular wave level. Is output to the gate driver 28A to the U-phase positive section (to the Ua-phase positive voltage output transistor).
When the U-phase signal is at a negative level, the triangular wave generator 3
High level H when 0A is below the level of the triangular wave given,
When the level of the triangular wave is exceeded, a low-level L signal is sent to the U-phase negative section (to the Ua-phase negative voltage output transistor).
Is output to the gate driver 28A. V-phase signal and W
The same applies to the phase signal. Gate driver 28A
Turns on / off the transistors of the transistor bridge 27A in response to the signals addressed to these phases, positive and negative sections. As a result, the power supply connection terminal TUa has three terminals.
A phase alternating Ua phase voltage is output, a similar Va phase voltage is output to a power supply connection terminal TVa, and a power supply connection terminal TWa
Output the same Wa phase voltage, and
The level between the peak and the lower peak is determined by the coil voltage command value VdcA. In this embodiment, the frequency of the three-phase voltage is determined by the frequency command value FH (the center value is 10 Hz). That is,
The three-phase AC voltage having a frequency of FH (for example, 10 Hz) of the peak voltage value (thrust) designated by the coil voltage command value VdcA is applied to the electric coils C1-2 and C5- shown in FIGS.
6, C9-10. The power supply circuit 20B determines the voltage level of the three-phase AC voltage based on the coil voltage command value VdcB output from the control circuit P, and sets the frequency of the three-phase AC voltage based on the frequency command value FL. The power supply circuit 20B outputs the three-phase AC voltages (Ub, V
b, Wb) are connected to the power connection terminals TVb, TUb, Tb, respectively.
Electric coils C12-11, C16-15 through Wb
C19-20. FIG. 5 shows electric coils C12-11 and C16.
The configuration of a power supply circuit 20B for supplying a low-frequency three-phase alternating current to -15 and C19-20 is shown. The power supply circuit 20B generates a lower frequency (center value is 5 Hz) than the power supply circuit 20A, and thus has only low frequency characteristics of constituent elements (parts). The system configuration and operation are the same as those of the power supply circuit 20A. Is omitted. Finally, a three-phase AC Ub-phase voltage is output to the power supply connection terminal TUb,
A similar Vb phase voltage is output to Vb, and a similar Wb phase voltage is output to power supply connection terminal TWb. The level between the upper and lower peaks of these voltages is determined by the coil voltage command value VdcB, and the frequency of the three-phase voltage is determined by the frequency command value FL in this embodiment. That is, the peak voltage value (thrust) specified by the coil voltage command value VdcB
The three-phase AC voltage having a frequency of FL (for example, 5 Hz) is supplied to the electric coils C12-11 and C16-1 shown in FIGS.
5, C19-20. FIG. 6 shows the distribution of the electromagnetic force applied to the molten steel MM by the electromagnet 1 by decomposing the distribution by the power supply circuit 20A (dotted line) and the distribution by the power supply circuit 20B (dashed line). It is the graph showing the electromagnetic force distribution (solid line). In the graph, the vertical axis indicates the magnitude of the electromagnetic force in the molten steel MM, the direction of the arrow pointing upward from the origin O is the clockwise direction corresponding to the paper of FIG. 1, and the opposite is the counterclockwise direction corresponding to the paper of FIG. It is. The horizontal axis represents the distance in the x direction from the origin O of the mold M, and σ represents the position of the inner wall surface of the mold M. Referring to the graph, the power supply circuit 20A applies a moving magnetic field (thrust force) in the clockwise direction to the molten steel MM.
In contrast, the power supply circuit 20B applies a moving magnetic field (thrust) in the counterclockwise direction to the molten steel MM. And
Two power supply circuits 20A, 20A having different three-phase AC voltage frequencies
As shown in FIG. 1 and FIG. 6, the subtraction of the thrust given by 0B indicates the molten steel MM in the mold M by a dotted arrow Fa on the paper surface of FIG. 1 along each side in a region near the mold side of the mold M. In a region closer to the origin O, which is further rotated in the clockwise direction and further inside, a dashed-dotted arrow F on the paper of FIG.
It is driven to rotate counterclockwise about the origin O indicated by b. According to this embodiment, the molten steel MM in the mold M is stirred in different directions at the center (near the origin O) of the mold M and near the sides of the mold. As a result, the stirring efficiency is improved, the inner surface of the mold is wiped, and the floating of bubbles is promoted. That is, while improving the quality of the product,
Seizure is prevented. Further, in this embodiment, a high-frequency power supply circuit 20A and a low-frequency power supply circuit 20B are used, and a total of two three-phase AC power supplies according to the frequency is used without using an expensive and large-capacity three-phase AC power supply in a wide frequency band. And an electric coil for applying a three-phase AC voltage. A three-phase AC power supply in a narrow frequency band is easier to design and has less expensive components than a three-phase AC power supply in a wide frequency band. Moreover, each power supply circuit 20A, 2
Since OB outputs a sine wave voltage, the circuit configuration is simple, and the flow control device uses a low-cost three-phase AC power supply. The high frequency magnetic field has low permeability to the molten steel MM, and the high frequency magnetic flux tends to concentrate on the surface of the core 5, particularly on the edge. The eddy current induced by this causes a local high temperature rise at the tooth tip between the slots of the core 5, the slot bottom, and the outer peripheral edge. Therefore, in the above-described embodiment, as shown in FIGS. 2 and 3, near the electric coil of the first group to which the high frequency is applied, the tooth tips between the slots, the slot bottom, and the outer peripheral edge are provided with: The tooth end slit Gs, the slot bottom slit Ss, and the back slit Bs, which extend in the radial direction, are cut to cut off the eddy current. Since these slits are located at each edge of the core 5 as shown in FIG. 2, a pair is formed at one location in the circumferential direction. This reduced the local temperature rise. In this embodiment, the power supply circuit 20A
The directions of the three-phase AC voltages applied to the electric coils by the power supply circuit 20B and the power supply circuit 20B are different between the first group and the second group. However, the direction of the three-phase AC voltage applied to each electric coil of the electromagnet 1 may be changed only in frequency in the same direction. In this case, the connection between the electric coil of the first group and the electric coil of the second group is completely the same, and the other configuration is the same as the configuration of the above-described embodiment.
According to this, in a region near the mold side of the mold M and a region further inside and near the origin O, thrusts having different magnitudes are generated in the same direction. The molten steel MM is rotationally driven in the same direction but at a different flow rate in a region near the mold side of the mold M and a region further inside and near the origin O. That is, the flow velocity of the molten steel MM in a region near the origin O can be adjusted.
This has the same effect as in the above-described embodiment.
【図面の簡単な説明】
【図1】 本発明の一実施例の全体構成を示すブロック
図である。
【図2】 図1に示す鋳型M,電磁石1の縦断面図(図
1の2A−2A線断面図)である。
【図3】 図1に示す鋳型M,電磁石1の拡大横断面図
であり、電気コイルC1〜C24のコイル間結線も示
す。
【図4】 図1に示す電源回路20Aの構成を表す電気
回路図である。
【図5】 図1に示す電源回路20Bの構成を表す電気
回路図である。
【図6】 図1に示す電磁石1が溶鋼MMに与える推力
の、鋳型幅方向の推力分布を示すグラフである。
【符号の説明】
1:電磁石 2:耐熱カバ−
3:空間 4:巻芯
5:電磁石コア 20A,20B:電源回路
C1〜C24:電気コイル M:連続鋳造鋳型
M1:銅板 M2:非磁性ステンレス板
MM:溶融金属 P:制御回路
U,V,W:3相交流電圧
TUa,TVa,TWa,TUb,TVb,TWb:電
源接続端子BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention. 2 is a longitudinal sectional view (a sectional view taken along line 2A-2A in FIG. 1) of the mold M and the electromagnet 1 shown in FIG. FIG. 3 is an enlarged cross-sectional view of the mold M and the electromagnet 1 shown in FIG. 1, and also shows connection between electric coils C1 to C24. FIG. 4 is an electric circuit diagram showing a configuration of a power supply circuit 20A shown in FIG. FIG. 5 is an electric circuit diagram showing a configuration of a power supply circuit 20B shown in FIG. 6 is a graph showing a thrust distribution in a mold width direction of a thrust given to molten steel MM by the electromagnet 1 shown in FIG. [Description of Signs] 1: Electromagnet 2: Heat-resistant cover 3: Space 4: Core 5: Electromagnet core 20A, 20B: Power supply circuit C1 to C24: Electric coil M: Continuous casting mold M1: Copper plate M2: Non-magnetic stainless plate MM: molten metal P: control circuit U, V, W: three-phase AC voltage TUa, TVa, TWa, TUb, TVb, TWb: power supply connection terminal
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7,DB名) H02K 44/00 B22D 11/00 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) H02K 44/00 B22D 11/00
Claims (1)
複数個の電気コイルを有する電磁石; 前記複数個の電気コイルの第1グル−プのものに、前記
方向に移動する磁界を発生するための位相差がある、第
1周波数の交流電圧を印加する第1通電手段;および、 前記複数個の電気コイルの第2グル−プのものに、前記
方向に移動する磁界を発生するための位相差がある、第
1周波数とは異なる第2周波数の交流電圧を印加する第
2通電手段; を備え、該第2通電手段が、電気コイルの並び方向に関
して、第1通電手段が第1グル−プの電気コイルに加え
る交流電圧の相順と逆の相順で第2グル−プの電気コイ
ルに交流電圧を印加することを特徴とする移動磁界発生
装置。(57) An electromagnet having a core and a plurality of electric coils distributed in a direction in which the core extends; A first energizing means for applying an AC voltage of a first frequency having a phase difference for generating a magnetic field moving in the direction; and a second group of the plurality of electric coils, a phase difference for generating a moving magnetic field, second current supply means for applying an alternating voltage of a second frequency different from the first frequency; comprises a second energizing means, regarding the direction of arrangement of the electrical coils
Then, the first energizing means is added to the electric coil of the first group.
The second group of electric coils in a phase sequence opposite to that of the AC voltage
A moving magnetic field generator characterized by applying an AC voltage to the moving magnetic field.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP28624195A JP3452709B2 (en) | 1995-11-02 | 1995-11-02 | Moving magnetic field generator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP28624195A JP3452709B2 (en) | 1995-11-02 | 1995-11-02 | Moving magnetic field generator |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH09131046A JPH09131046A (en) | 1997-05-16 |
JP3452709B2 true JP3452709B2 (en) | 2003-09-29 |
Family
ID=17701816
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP28624195A Expired - Fee Related JP3452709B2 (en) | 1995-11-02 | 1995-11-02 | Moving magnetic field generator |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3452709B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2437381A2 (en) | 2010-09-29 | 2012-04-04 | Sanyo Denki Co., Ltd. | Moving magnetic field generating apparatus |
CN109909467A (en) * | 2019-03-14 | 2019-06-21 | 燕山大学 | Layer-stepping coil M-emss |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100338698B1 (en) * | 1999-08-17 | 2002-05-30 | 신현준 | Frequency-variable field generater |
JP5018144B2 (en) * | 2007-03-09 | 2012-09-05 | Jfeスチール株式会社 | Steel continuous casting method |
CN107134905B (en) * | 2017-04-27 | 2019-12-03 | 南京航空航天大学 | A kind of stator three-phase-multiphase Dual stator-winding induction generator system |
-
1995
- 1995-11-02 JP JP28624195A patent/JP3452709B2/en not_active Expired - Fee Related
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2437381A2 (en) | 2010-09-29 | 2012-04-04 | Sanyo Denki Co., Ltd. | Moving magnetic field generating apparatus |
US8917087B2 (en) | 2010-09-29 | 2014-12-23 | Sanyo Denki Co., Ltd. | Moving magnetic field generating apparatus |
US9613740B2 (en) | 2010-09-29 | 2017-04-04 | Sanyo Denki Co., Ltd. | Electric apparatus with moving magnetic field generating apparatus |
CN109909467A (en) * | 2019-03-14 | 2019-06-21 | 燕山大学 | Layer-stepping coil M-emss |
CN109909467B (en) * | 2019-03-14 | 2020-01-10 | 燕山大学 | Layered coil crystallizer electromagnetic stirrer |
Also Published As
Publication number | Publication date |
---|---|
JPH09131046A (en) | 1997-05-16 |
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