而在磁粉離合器調速系統中。磁粉離合器轉矩的變化與勵磁電流基本呈線性關系，這樣就能通過電刷供電后，調節勵磁電流以準確地控制轉矩的大小，應答及時，并能顯示很好的重復性。而且，從圖4中看出，輸出轉矩對應于某一電流值，而與轉速無關，通過調整勵磁電流值，既可保持定轉矩輸出，又能自由改變轉矩值，從而得到更寬的調速范圍，當采用剩磁很少的工業純鐵制作磁粉離合器時，調速范圍可以從零至額定轉矩。

對高層(ceng)建筑(zhu)電(dian)(dian)梯(ti)(ti)的(de)(de)(de)電(dian)(dian)機(ji)(ji)調(diao)速(su)(su)(su)系(xi)統要(yao)(yao)求(qiu)越(yue)來越(yue)高。既要(yao)(yao)求(qiu)舒適(shi)感好(hao)、平層(ceng)準確(que)度(du)高，隨著城市建筑(zhu)業的(de)(de)(de)發展(zhan)。又需要(yao)(yao)調(diao)速(su)(su)(su)性(xing)能好(hao)、調(diao)速(su)(su)(su)范(fan)圍(wei)(wei)大(da)。常用(yong)的(de)(de)(de)調(diao)速(su)(su)(su)電(dian)(dian)機(ji)(ji)有(you)交(jiao)流(liu)(liu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)和直流(liu)(liu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)。交(jiao)流(liu)(liu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)結(jie)構緊湊(cou)，維(wei)護(hu)(hu)簡單(dan)，價格較低，但(dan)舒適(shi)感較差，一(yi)般(ban)用(yong)載貨(huo)電(dian)(dian)梯(ti)(ti)，且調(diao)速(su)(su)(su)范(fan)圍(wei)(wei)窄，所控(kong)制的(de)(de)(de)電(dian)(dian)梯(ti)(ti)速(su)(su)(su)度(du)在(zai)1米(mi)(mi)/秒(miao)以下。直流(liu)(liu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)具有(you)調(diao)速(su)(su)(su)性(xing)能好(hao)，調(diao)速(su)(su)(su)范(fan)圍(wei)(wei)大(da)的(de)(de)(de)特點(dian)，控(kong)制的(de)(de)(de)電(dian)(dian)梯(ti)(ti)速(su)(su)(su)度(du)達4米(mi)(mi)/秒(miao)，但(dan)機(ji)(ji)組結(jie)構體積大(da)，耗電(dian)(dian)多，維(wei)護(hu)(hu)工作量多，造(zao)價高，主要(yao)(yao)適(shi)用(yong)于(yu)電(dian)(dian)梯(ti)(ti)的(de)(de)(de)額定(ding)速(su)(su)(su)度(du)在(zai)2米(mi)(mi)/秒(miao)或2米(mi)(mi)/秒(miao)以上(shang)(shang)的(de)(de)(de)各類電(dian)(dian)梯(ti)(ti)上(shang)(shang)。1984年，第一(yi)臺用(yong)變頻(pin)變壓(ya)(VVVF系(xi)統控(kong)制的(de)(de)(de)電(dian)(dian)梯(ti)(ti)問世，所控(kong)制的(de)(de)(de)速(su)(su)(su)度(du)可達6米(mi)(mi)/秒(miao)，體積小，重量輕(qing)(qing)，效率(lv)(lv)高+節省(sheng)能源，但(dan)價格昂貴，調(diao)速(su)(su)(su)范(fan)圍(wei)(wei)受到(dao)頻(pin)率(lv)(lv)變化(hua)影響，調(diao)速(su)(su)(su)不可能從(cong)(cong)0-額定(ding)轉(zhuan)速(su)(su)(su)+而從(cong)(cong)實際應用(yong)中看，還易引起(qi)故障。為此，根(gen)據磁粉離合器的(de)(de)(de)工作特性(xing)，將其應用(yong)于(yu)電(dian)(dian)梯(ti)(ti)電(dian)(dian)機(ji)(ji)調(diao)速(su)(su)(su)系(xi)統中+采(cai)用(yong)交(jiao)流(liu)(liu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)驅動(dong)(dong)(dong)，達到(dao)直流(liu)(liu)電(dian)(dian)動(dong)(dong)(dong)機(ji)(ji)的(de)(de)(de)調(diao)速(su)(su)(su)效果，且具有(you)體積小，重量輕(qing)(qing)，經濟、適(shi)用(yong)的(de)(de)(de)特性(xing)。

1設計方(fang)法及(ji)調速原理

不同(tong)之處在(zai)于采用普通交流電動(dong)(dong)機(ji)驅動(dong)(dong)，現設計的電梯(ti)調(diao)速(su)系統機(ji)構運動(dong)(dong)簡圖如圖l所(suo)示。這種結構主要(yao)有交流電動(dong)(dong)機(ji)、磁粉(fen)離合器(qi)、變(bian)速(su)機(ji)構、卷(juan)筒、滑輪組等組成。與其它電梯(ti)調(diao)速(su)系統相(xiang)比較。磁粉(fen)離合器(qi)參與調(diao)速(su)。

轉(zhuan)速(su)(su)公式為(wei)n=60f1*1一(yi)s/Pf1一(yi)電(dian)(dian)(dian)(dian)(dian)源(yuan)頻率(lv)p一(yi)極對數 s一(yi)轉(zhuan)差率(lv))如(ru)果均勻地改變(bian)定(ding)(ding)(ding)(ding)子(zi)的電(dian)(dian)(dian)(dian)(dian)源(yuan)頻率(lv)，對于交(jiao)流電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)。則(ze)可平滑地改變(bian)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)的同步轉(zhuan)速(su)(su)。許(xu)多情況下，需要(yao)(yao)(yao)保持調(diao)速(su)(su)時(shi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)的最(zui)大轉(zhuan)矩(ju)不變(bian)。周電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)轉(zhuan)矩(ju)m=k2u1/f1k2為(wei)常數，u1為(wei)定(ding)(ding)(ding)(ding)子(zi)繞組(zu)電(dian)(dian)(dian)(dian)(dian)壓(ya)，f1為(wei)定(ding)(ding)(ding)(ding)子(zi)供(gong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源(yuan)頻率(lv))．若(ruo)要(yao)(yao)(yao)保證電(dian)(dian)(dian)(dian)(dian)磁轉(zhuan)矩(ju)為(wei)定(ding)(ding)(ding)(ding)值，即u1定(ding)(ding)(ding)(ding)值，則(ze)在改變(bian)電(dian)(dian)(dian)(dian)(dian)源(yuan)顴率(lv)的同時(shi)，要(yao)(yao)(yao)求(qiu)定(ding)(ding)(ding)(ding)供(gong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)也要(yao)(yao)(yao)作相應的調(diao)整。

其中(zhong)1為(wei)金(jin)屬外(wai)筒(tong)，2為(wei)磁粉(fen)．3為(wei)勵磁線圈(quan)(quan)，4為(wei)電(dian)(dian)磁轉子(zi)．5為(wei)導電(dian)(dian)環。1與4之(zhi)間留有少(shao)量間隙，一般為(wei)1．52mm內裝極擻小的(de)(de)耐磨球狀磁性(xing)粉(fen)末(mo)，當勵磋線圈(quan)(quan)中(zhong)無(wu)電(dian)(dian)流時，散抄似的(de)(de)粉(fen)柬(jian)不阻礙主從(cong)動件(jian)之(zhi)間的(de)(de)楣對(dui)運動，離合器(qi)(qi)處(chu)于分離狀態；當通(tong)人電(dian)(dian)流時，電(dian)(dian)磁粉(fen)末(mo)即(ji)在磁場作用下被吸(xi)引磁化聚集(ji)，并沿(yan)氣隙磁路形(xing)成鏈狀固體(ti)，通(tong)過其結合力，將主從(cong)動件(jian)聯系(xi)起來，離合器(qi)(qi)即(ji)接合。