速度繼電器又稱反接製動繼電器。它的主要結構是由轉子、定子及觸點三部分組成。

　　速(su)度(du)繼(ji)電(dian)器(qi)主(zhu)要(yao)用(yong)於(yu)三(san)相(xiang)異(yi)步(bu)電(dian)動(dong)機(ji)反(fan)接(jie)製(zhi)動(dong)的(de)控(kong)製(zhi)電(dian)路(lu)中(zhong)
，它(ta)的(de)任(ren)務(wu)是(shi)當(dang)三(san)相(xiang)電(dian)源(yuan)的(de)相(xiang)序(xu)改(gai)變(bian)以(yi)後(hou)，產(chan)生(sheng)與(yu)實(shi)際(ji)轉(zhuan)子(zi)轉(zhuan)動(dong)方(fang)向(xiang)相(xiang)反(fan)的(de)旋(xuan)轉(zhuan)磁(ci)場(chang)，從(cong)而(er)產(chan)生(sheng)製(zhi)動(dong)力(li)矩(ju)。因(yin)此(ci)，使(shi)電(dian)動(dong)機(ji)在(zai)製(zhi)動(dong)狀(zhuang)態(tai)下(xia)迅(xun)速(su)降(jiang)低(di)速(su)度(du)。在(zai)電(dian)機(ji)轉(zhuan)速(su)接(jie)近(jin)零(ling)時(shi)立(li)即(ji)發(fa)出(chu)信(xin)號(hao)
，切(qie)斷(duan)電(dian)源(yuan)使(shi)之(zhi)停(ting)車(che)（否則電動機開始反方向起動）。

　　tadezhuanzishiyigeyongjiucitie，yudiandongjihuojixiezhoulianjie，suizhediandongjixuanzhuanerxuanzhuan。dingziyushulongzhuanzixiangsi，neiyouduanlutiao，tayenengweiraozhezhuanzhouzhuandong。dangzhuanzisuidiandongjizhuandongshi
，tadecichangyudingziduanlutiaoxiangqiege
，chanshengganyingdianshijiganyingdianliu
，zheyudiandongjidegongzuoyuanlixiangtong，gudingzisuizhezhuanzizhuandongerzhuandongqilai。dingzizhuandongshidaidongganggan，ganggantuidongchudian
，shizhibiheyufenduan。dangdiandongjixuanzhuanfangxianggaibianshi，jidianqidezhuanziyudingzidezhuanxiangyegaibian
，zheshidingzijiukeyichudonglingwaiyizuchudian
，shizhifenduanyubihe。dangdiandongjitingzhishi

，jidianqidechudianjihuifuyuanlaidejingzhizhuangtai。

　　由you於yu繼ji電dian器qi工gong作zuo時shi是shi與yu電dian動dong機ji同tong軸zhou的de，不bu論lun電dian動dong機ji正zheng轉zhuan或huo反fan轉zhuan，電dian器qi的de兩liang個ge常chang開kai觸chu點dian

，就jiu有you一yi個ge閉bi合he，準zhun備bei實shi行xing電dian動dong機ji的de製zhi動dong。一yi旦dan開kai始shi製zhi動dong時shi
，由you控kong製zhi係xi統tong的de聯lian鎖suo觸chu點dian和he速su度du繼ji電dian器qi的de備bei用yong的de閉bi合he觸chu點dian
，形xing成cheng一yi個ge電dian動dong機ji相xiang序xu反fan接jie（俗稱倒相）電dian路lu，使shi電dian動dong機ji在zai反fan接jie製zhi動dong下xia停ting車che。而er當dang電dian動dong機ji的de轉zhuan速su接jie近jin零ling時shi，速su度du繼ji電dian器qi的de製zhi動dong常chang開kai觸chu點dian分fen斷duan
，從cong而er切qie斷duan電dian源yuan，使shi電dian動dong機ji製zhi動dong狀zhuang態tai結jie束shu。