一、電機的種類有哪些
1、按工作電源種類劃分
可分(fen)為直流(liu)電機和(he)交流(liu)電機。
2、按結構及工作原理劃分
無刷(shua)直流電(dian)機(ji)和(he)有刷(shua)直流電(dian)機(ji)、永(yong)磁直流電(dian)機(ji)和(he)電(dian)磁直流電(dian)機(ji)。
(1)永磁直(zhi)流電機(ji)按(an)材(cai)料又分為稀土、鐵氧(yang)體、鋁(lv)鎳鈷(gu)永磁直(zhi)流電機(ji)。
(2)電(dian)磁直流電(dian)機(ji)按勵(li)磁方式(shi)又(you)分為(wei)串(chuan)勵(li)、并勵(li)、他勵(li)和復(fu)勵(li)直流電(dian)機(ji)。
(3)交流電(dian)(dian)機(ji)可分:單相(xiang)電(dian)(dian)機(ji)和(he)三相(xiang)電(dian)(dian)機(ji)
3、按用途分
有(you)驅動電機(ji)和控制(zhi)用(yong)電機(ji)。
4、按運轉速度分
有(you)高速電(dian)機、低速電(dian)機、恒速電(dian)機和調速電(dian)機。
低(di)速電(dian)動(dong)機又(you)分(fen)為(wei)齒(chi)輪(lun)減速電(dian)動(dong)機、電(dian)磁減速電(dian)動(dong)機、力矩電(dian)動(dong)機和爪極同步電(dian)動(dong)機等(deng)。
二、不同類型電機的特點
1、無刷直流電動機
無(wu)刷(shua)(shua)直(zhi)流(liu)(liu)電(dian)(dian)機(ji)(ji)(ji)(ji)是(shi)在有刷(shua)(shua)直(zhi)流(liu)(liu)電(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)基礎上發(fa)展(zhan)來的(de),但它的(de)驅動(dong)電(dian)(dian)流(liu)(liu)是(shi)不折不扣的(de)交流(liu)(liu)。無(wu)刷(shua)(shua)直(zhi)流(liu)(liu)電(dian)(dian)機(ji)(ji)(ji)(ji)又(you)可以分為(wei)無(wu)刷(shua)(shua)速率電(dian)(dian)機(ji)(ji)(ji)(ji)和無(wu)刷(shua)(shua)力矩電(dian)(dian)機(ji)(ji)(ji)(ji)。一(yi)(yi)般(ban)(ban)地,無(wu)刷(shua)(shua)電(dian)(dian)機(ji)(ji)(ji)(ji)的(de)驅動(dong)電(dian)(dian)流(liu)(liu)有兩種(zhong),一(yi)(yi)種(zhong)是(shi)梯形波(bo)(一(yi)(yi)般(ban)(ban)是(shi)“方波(bo)”),另一(yi)(yi)種(zhong)是(shi)正弦波(bo)。有時候把前(qian)一(yi)(yi)種(zhong)叫(jiao)直(zhi)流(liu)(liu)無(wu)刷(shua)(shua)電(dian)(dian)機(ji)(ji)(ji)(ji),后一(yi)(yi)種(zhong)叫(jiao)交流(liu)(liu)伺服(fu)電(dian)(dian)機(ji)(ji)(ji)(ji),確切地講是(shi)交流(liu)(liu)伺服(fu)電(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)的(de)一(yi)(yi)種(zhong)。
無(wu)刷直(zhi)流電(dian)(dian)機為了(le)減少轉(zhuan)(zhuan)動慣量(liang),通常采(cai)用“細長”的結構。無(wu)刷直(zhi)流電(dian)(dian)機在重量(liang)和體積上要比有刷直(zhi)流電(dian)(dian)機小(xiao)的多,相應的轉(zhuan)(zhuan)動慣量(liang)可(ke)以減少40%—50%左右。由(you)于永磁材料(liao)的加工問題,致使無(wu)刷直(zhi)流電(dian)(dian)機一般的容量(liang)都在100kW以下(xia)。
這(zhe)種電(dian)動機(ji)的(de)(de)機(ji)械(xie)特(te)性和調節特(te)性的(de)(de)線性度好,調速范圍廣,壽命(ming)長,維(wei)護方便噪聲小(xiao),不存在(zai)因電(dian)刷而引起(qi)的(de)(de)一系列(lie)問題,所以(yi)這(zhe)種電(dian)動機(ji)在(zai)控(kong)制系統中(zhong)有很大(da)的(de)(de)應用(yong)潛力。
2、步進電動機
所謂步(bu)(bu)進(jin)(jin)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)就(jiu)是一(yi)種(zhong)將電(dian)(dian)脈(mo)(mo)沖(chong)轉化(hua)為角(jiao)位移的(de)(de)執行機(ji)(ji)(ji)構。更(geng)通俗一(yi)點(dian)講(jiang):當(dang)步(bu)(bu)進(jin)(jin)驅動(dong)(dong)(dong)(dong)(dong)(dong)器接收(shou)到一(yi)個脈(mo)(mo)沖(chong)信號,它(ta)就(jiu)驅動(dong)(dong)(dong)(dong)(dong)(dong)步(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)(ji)(ji)按設(she)定(ding)的(de)(de)方向轉動(dong)(dong)(dong)(dong)(dong)(dong)一(yi)個固(gu)定(ding)的(de)(de)角(jiao)度。我們可(ke)以(yi)通過控制(zhi)脈(mo)(mo)沖(chong)的(de)(de)個數來控制(zhi)電(dian)(dian)機(ji)(ji)(ji)的(de)(de)角(jiao)位移量(liang),從而達(da)到精確定(ding)位的(de)(de)目(mu)的(de)(de)。同時(shi)還可(ke)以(yi)通過控制(zhi)脈(mo)(mo)沖(chong)頻率來控制(zhi)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)轉動(dong)(dong)(dong)(dong)(dong)(dong)的(de)(de)速(su)度和加速(su)度,從而達(da)到調速(su)的(de)(de)目(mu)的(de)(de)。目(mu)前(qian),比較常(chang)用(yong)的(de)(de)步(bu)(bu)進(jin)(jin)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)包括反(fan)應式步(bu)(bu)進(jin)(jin)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(VR)、永磁式步(bu)(bu)進(jin)(jin)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(PM)、混合式步(bu)(bu)進(jin)(jin)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)(HB)和單相式步(bu)(bu)進(jin)(jin)電(dian)(dian)動(dong)(dong)(dong)(dong)(dong)(dong)機(ji)(ji)(ji)等。
步(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)機和普通電(dian)動(dong)(dong)(dong)機的(de)區別(bie)主(zhu)要(yao)就(jiu)在(zai)(zai)于(yu)其脈(mo)沖(chong)驅(qu)動(dong)(dong)(dong)的(de)形式,正是(shi)這(zhe)個(ge)(ge)特(te)點,步(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)機可(ke)以(yi)和現(xian)代(dai)的(de)數(shu)字控制(zhi)(zhi)技術相結(jie)合。但(dan)步(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)機在(zai)(zai)控制(zhi)(zhi)精度(du)、速度(du)變(bian)化范圍(wei)、低(di)速性能方面(mian)都不如(ru)傳統閉環(huan)控制(zhi)(zhi)的(de)直(zhi)(zhi)流伺服電(dian)動(dong)(dong)(dong)機。所(suo)(suo)以(yi)主(zhu)要(yao)應(ying)用(yong)在(zai)(zai)精度(du)要(yao)求(qiu)不是(shi)特(te)別(bie)高(gao)的(de)場合。由于(yu)步(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)機具有(you)結(jie)構簡單、可(ke)靠(kao)性高(gao)和成(cheng)本低(di)的(de)特(te)點,所(suo)(suo)以(yi)步(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)機廣泛應(ying)用(yong)在(zai)(zai)生產實踐的(de)各個(ge)(ge)領域。尤其是(shi)在(zai)(zai)數(shu)控機床(chuang)制(zhi)(zhi)造領域,由于(yu)步(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)機不需要(yao)A/D轉(zhuan)(zhuan)換,能夠直(zhi)(zhi)接(jie)將數(shu)字脈(mo)沖(chong)信(xin)號轉(zhuan)(zhuan)化成(cheng)為角(jiao)位移,所(suo)(suo)以(yi)一直(zhi)(zhi)被認為是(shi)最理(li)想的(de)數(shu)控機床(chuang)執行元件。
除了在(zai)(zai)數控機床上的(de)應用(yong),步進電機也(ye)可(ke)以用(yong)在(zai)(zai)其他的(de)機械上,比如作(zuo)為(wei)自動送(song)料機中的(de)馬(ma)達(da)(da),作(zuo)為(wei)通用(yong)的(de)軟盤驅動器(qi)的(de)馬(ma)達(da)(da),也(ye)可(ke)以應用(yong)在(zai)(zai)打印機和繪圖儀中。
此(ci)外,步進電(dian)動(dong)機也存在許多(duo)缺陷。由于(yu)步進電(dian)機存在空載啟(qi)動(dong)頻率(lv),所以(yi)步進電(dian)機可以(yi)低速(su)正(zheng)常運轉,但若高于(yu)一定(ding)速(su)度時就無法啟(qi)動(dong),并(bing)伴(ban)有尖銳的(de)嘯叫聲。不同廠家的(de)細(xi)分驅動(dong)器精(jing)度可能差別很大,細(xi)分數(shu)越(yue)大精(jing)度越(yue)難控制。并(bing)且,步進電(dian)機低速(su)轉動(dong)時有較大的(de)振動(dong)和噪聲。
3、伺服電動機
伺服電動機廣泛應用于各種控制系統中(zhong),能將輸(shu)入(ru)的電壓信號(hao)轉換(huan)為電機軸上的機械輸(shu)出量,拖動被控制元(yuan)件,從而達(da)到控制目的。
伺(si)服電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)有直(zhi)(zhi)流(liu)和交(jiao)流(liu)之(zhi)分。最早的(de)伺(si)服電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)是一(yi)般的(de)直(zhi)(zhi)流(liu)電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji),在(zai)控(kong)(kong)制(zhi)(zhi)(zhi)精度不(bu)高的(de)情況下,才(cai)采用(yong)一(yi)般的(de)直(zhi)(zhi)流(liu)電(dian)(dian)(dian)機(ji)(ji)(ji)(ji)做伺(si)服電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)。目前的(de)直(zhi)(zhi)流(liu)伺(si)服電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji)從結構上講,就是小功率的(de)直(zhi)(zhi)流(liu)電(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)(ji),其勵磁多采用(yong)電(dian)(dian)(dian)樞(shu)控(kong)(kong)制(zhi)(zhi)(zhi)和磁場(chang)控(kong)(kong)制(zhi)(zhi)(zhi),但通常采用(yong)電(dian)(dian)(dian)樞(shu)控(kong)(kong)制(zhi)(zhi)(zhi)。
旋(xuan)轉電機(ji)的(de)(de)分類,直流伺服電動機(ji)在機(ji)械特性上能夠很(hen)好的(de)(de)滿足(zu)控(kong)制系統的(de)(de)要求,但(dan)是由于換向(xiang)(xiang)器的(de)(de)存(cun)(cun)在,存(cun)(cun)在許多(duo)的(de)(de)不足(zu):換向(xiang)(xiang)器與電刷(shua)之間易產生(sheng)火花,干擾驅動器工(gong)作,不能應用在有可燃氣體的(de)(de)場合(he)。電刷(shua)和換向(xiang)(xiang)器存(cun)(cun)在摩擦(ca),會產生(sheng)較(jiao)大(da)的(de)(de)死區。結構復雜,維護比較(jiao)困難。
交流伺服電(dian)動機本質上是一種(zhong)(zhong)兩(liang)相異步電(dian)動機,其控(kong)制方法主(zhu)要有三種(zhong)(zhong):幅值(zhi)控(kong)制、相位控(kong)制和幅相控(kong)制。
一(yi)般(ban)地(di),伺服電(dian)(dian)動(dong)(dong)機(ji)要(yao)求電(dian)(dian)動(dong)(dong)機(ji)的轉(zhuan)速(su)要(yao)受(shou)所加電(dian)(dian)壓(ya)信號的控制(zhi)(zhi)。轉(zhuan)速(su)能夠(gou)隨(sui)著所加電(dian)(dian)壓(ya)信號的變(bian)化(hua)而連續變(bian)化(hua)。電(dian)(dian)動(dong)(dong)機(ji)的反(fan)映要(yao)快(kuai)、體(ti)積要(yao)小、控制(zhi)(zhi)功(gong)率要(yao)小。伺服電(dian)(dian)動(dong)(dong)機(ji)主要(yao)應用(yong)在各(ge)種運動(dong)(dong)控制(zhi)(zhi)系統中(zhong),尤其是隨(sui)動(dong)(dong)系統。
4、力矩電動機
所謂的(de)力(li)矩(ju)電動(dong)(dong)機是一種扁平型多極永磁直(zhi)流電動(dong)(dong)機。其電樞有較多的(de)槽數、換向片數和(he)(he)串聯導體數,以降低轉矩(ju)脈動(dong)(dong)和(he)(he)轉速脈動(dong)(dong)。力(li)矩(ju)電動(dong)(dong)機有直(zhi)流力(li)矩(ju)電動(dong)(dong)機和(he)(he)交流力(li)矩(ju)電動(dong)(dong)機兩種。
其中,直流力矩電動機的(de)自感電抗很小(xiao),所以(yi)響應(ying)性(xing)很好。其輸(shu)出力矩與輸(shu)入電流成正比,與轉(zhuan)子的(de)速(su)度和位置(zhi)無關。它可以(yi)在接近堵轉(zhuan)狀態(tai)下直接和負載連接低速(su)運行而不用(yong)齒輪減速(su),所以(yi)在負載的(de)軸上能產生很高的(de)力矩對慣性(xing)比,并能消(xiao)除(chu)由于使用(yong)減速(su)齒輪而產生的(de)系統誤差。
交流力(li)矩(ju)電(dian)(dian)動(dong)機又可以(yi)分為同步(bu)(bu)和(he)異(yi)步(bu)(bu)兩種,目前常(chang)用的(de)(de)是鼠(shu)籠型(xing)異(yi)步(bu)(bu)力(li)矩(ju)電(dian)(dian)動(dong)機,它具有低轉速(su)和(he)大(da)力(li)矩(ju)的(de)(de)特(te)點(dian)。一般地,在(zai)紡織(zhi)工業中經(jing)常(chang)使(shi)用交流力(li)矩(ju)電(dian)(dian)動(dong)機,其(qi)工作原理和(he)結構和(he)單(dan)相異(yi)步(bu)(bu)電(dian)(dian)動(dong)機的(de)(de)相同,但是由于(yu)鼠(shu)籠型(xing)轉子(zi)的(de)(de)電(dian)(dian)阻(zu)較大(da),所以(yi)其(qi)機械特(te)性較軟。