三相異步電機的轉(zhuǎn)速與轉(zhuǎn)向SpeedandDirectionofThree-PhaseAsynchronousMotor旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle取決于三相電流的相序。旋轉(zhuǎn)磁場方向：U1V1W1

與三相電流的相序：L1→

L2→

L3一致。U1U2V1V2W2W1L1L2L3U1U2V1V2W1W2i2i1i3i1i2ImOti3旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle如何改變旋轉(zhuǎn)磁場的旋轉(zhuǎn)方向？L1L2L3U1U2V1V2W1W2i2i1i3L1L3L2U1U2V1V2W1W2i3i1i2U1V1W1U1V1W1U1V1W1U1V1W1交換任意兩根電源線改變電流相序旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle▲極對數(shù)（p）的概念：以Y型接法為例，當每相繞組只有一個線圈時，按右下圖放入定子槽內(nèi)，合成的旋轉(zhuǎn)磁場只有一對磁極，則極對數(shù)為1。即p=1。U1U2V1V2W2W1L1L2L3U1U2V1V2W1W2i2i1i3旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle以Y型接法為例，將每相繞組都改用兩個線圈串聯(lián)組成。按下圖放入定子槽內(nèi)。形成的磁場則是兩對磁極。即p=2

i3W2V4U1V1W1U2V2W3U3U4V3W4i1i2U1U2U3U4V4V2V3W4W1W2W3L1L2L3V1旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principleU1U2V1V2W2W1ωt=0ωt=π/2U1U2V1V2W2W1U1U2V1V2W2W1ωt=πωt=3π/2U1U2V1V2W2W1ωt=2πU1U2V1V2W2W1iuivImOωtiw2π0π/2π3π/2P=1旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle電流變化一周→旋轉(zhuǎn)磁場轉(zhuǎn)一圈電流每秒鐘變化50周→旋轉(zhuǎn)磁場轉(zhuǎn)50圈→旋轉(zhuǎn)磁場轉(zhuǎn)3000圈電流每分鐘變化(50×60)周p=1

時：旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principleiuivImOωtiw2π0π/2π3π/2P=2ωt=

0U1U2U3U4V1V4V2V3W4W1W2W3NNSSωt=π/2U1U2U3U4V1V4V2V3W4W1W2W3NNSSωt=

3π/2U1U2U3U4W3W2W4W1V4V1V2V3NNSSωt=πU1U2U3U4V1V4V2V3W4W1W2W3NNSSωt=

2πU1U2U3U4V1V4V2V3W4W1W2W3NNSS旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle電流變化一周→旋轉(zhuǎn)磁場轉(zhuǎn)半圈電流每秒鐘變化50周→旋轉(zhuǎn)磁場轉(zhuǎn)25圈→旋轉(zhuǎn)磁場轉(zhuǎn)1500圈電流每分鐘變化(50×60)周p=2時：旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle600pfn=min）r/(

p123456n0/(r/min)300015001000750600500f=50Hz時,不同極對數(shù)時的同步轉(zhuǎn)速如下:p為任意值時，三相異步電動機的旋轉(zhuǎn)磁場的轉(zhuǎn)速（同步轉(zhuǎn)速）為：轉(zhuǎn)子的轉(zhuǎn)向與轉(zhuǎn)速principleNS轉(zhuǎn)子旋轉(zhuǎn)方向與旋轉(zhuǎn)磁場旋轉(zhuǎn)方向一致改變旋轉(zhuǎn)磁場方向就能改變電機旋轉(zhuǎn)方向任意調(diào)換三相異步電機的兩根進線，就能改變電源相序，改變電機的旋轉(zhuǎn)方向旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle①轉(zhuǎn)子轉(zhuǎn)速n=磁場轉(zhuǎn)速n0②轉(zhuǎn)子轉(zhuǎn)速n>磁場轉(zhuǎn)速n0②轉(zhuǎn)子轉(zhuǎn)速n<磁場轉(zhuǎn)速n0電機降速電機降速負載適當時，電機勻速運行旋轉(zhuǎn)磁場的轉(zhuǎn)向與轉(zhuǎn)速principle轉(zhuǎn)差率（S）：同步轉(zhuǎn)速與轉(zhuǎn)子轉(zhuǎn)速之差與同步轉(zhuǎn)速的比值。轉(zhuǎn)子未轉(zhuǎn)動時，n=0，s=1；電機理想空載時，n≈n0，s≈0。作為電動機，轉(zhuǎn)速在0~n0范圍內(nèi)變化，轉(zhuǎn)差率在0~1范圍內(nèi)變。三相異步電機的運行狀態(tài)principle狀態(tài)發(fā)電機電動機電磁制動實現(xiàn)外力使電機快速旋轉(zhuǎn)定子繞組接對稱電源外力使電機沿磁場反方向旋轉(zhuǎn)電磁轉(zhuǎn)矩制動驅(qū)動制動能量關系機械能轉(zhuǎn)變?yōu)殡娔茈娔苻D(zhuǎn)變?yōu)闄C械能電能和機械能變成內(nèi)能旋轉(zhuǎn)磁場的旋轉(zhuǎn)方向取決于三相電流的相序，改變電流相序就能改變旋轉(zhuǎn)磁場的