一、電機的種類有哪些
1、按工作電源種類劃分
可(ke)分為直流(liu)電(dian)機和交流(liu)電(dian)機。
2、按結構及工作原理劃分
無刷直(zhi)流(liu)電(dian)機和(he)有刷直(zhi)流(liu)電(dian)機、永(yong)磁直(zhi)流(liu)電(dian)機和(he)電(dian)磁直(zhi)流(liu)電(dian)機。
(1)永(yong)磁直流(liu)電(dian)機(ji)按材料又分為(wei)稀土、鐵氧體、鋁(lv)鎳(nie)鈷永(yong)磁直流(liu)電(dian)機(ji)。
(2)電(dian)磁(ci)直(zhi)(zhi)流電(dian)機(ji)(ji)按(an)勵(li)磁(ci)方式又分(fen)為串勵(li)、并勵(li)、他(ta)勵(li)和復勵(li)直(zhi)(zhi)流電(dian)機(ji)(ji)。
(3)交流(liu)電(dian)機(ji)(ji)可分:單相(xiang)電(dian)機(ji)(ji)和三相(xiang)電(dian)機(ji)(ji)
3、按用途分
有驅動電(dian)機和控制用電(dian)機。
4、按運轉速度分
有高(gao)速電(dian)機、低速電(dian)機、恒(heng)速電(dian)機和調速電(dian)機。
低速(su)電動(dong)(dong)(dong)(dong)機又分(fen)為齒輪減速(su)電動(dong)(dong)(dong)(dong)機、電磁減速(su)電動(dong)(dong)(dong)(dong)機、力矩(ju)電動(dong)(dong)(dong)(dong)機和爪極同步電動(dong)(dong)(dong)(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)直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)機(ji)是(shi)在有刷(shua)直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)動機(ji)的(de)基礎上發展來的(de),但(dan)它的(de)驅(qu)動電(dian)(dian)(dian)(dian)流(liu)(liu)是(shi)不(bu)折不(bu)扣的(de)交(jiao)流(liu)(liu)。無(wu)刷(shua)直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)機(ji)又可以分為無(wu)刷(shua)速率電(dian)(dian)(dian)(dian)機(ji)和(he)無(wu)刷(shua)力矩電(dian)(dian)(dian)(dian)機(ji)。一般(ban)地,無(wu)刷(shua)電(dian)(dian)(dian)(dian)機(ji)的(de)驅(qu)動電(dian)(dian)(dian)(dian)流(liu)(liu)有兩種(zhong),一種(zhong)是(shi)梯形波(一般(ban)是(shi)“方波”),另(ling)一種(zhong)是(shi)正弦波。有時候把前(qian)一種(zhong)叫(jiao)直(zhi)流(liu)(liu)無(wu)刷(shua)電(dian)(dian)(dian)(dian)機(ji),后一種(zhong)叫(jiao)交(jiao)流(liu)(liu)伺服電(dian)(dian)(dian)(dian)機(ji),確切地講是(shi)交(jiao)流(liu)(liu)伺服電(dian)(dian)(dian)(dian)動機(ji)的(de)一種(zhong)。
無(wu)(wu)刷直(zhi)(zhi)流(liu)(liu)電(dian)(dian)機(ji)為了減少轉動慣量(liang),通常(chang)采用(yong)“細長”的(de)結構。無(wu)(wu)刷直(zhi)(zhi)流(liu)(liu)電(dian)(dian)機(ji)在(zai)重量(liang)和(he)體積上要比有刷直(zhi)(zhi)流(liu)(liu)電(dian)(dian)機(ji)小的(de)多,相應的(de)轉動慣量(liang)可以減少40%—50%左右(you)。由于(yu)永(yong)磁材料(liao)的(de)加工(gong)問題,致使無(wu)(wu)刷直(zhi)(zhi)流(liu)(liu)電(dian)(dian)機(ji)一(yi)般的(de)容量(liang)都在(zai)100kW以下。
這種電動機的(de)機械(xie)特性和(he)調節(jie)特性的(de)線(xian)性度好,調速范圍廣,壽命長,維護方便(bian)噪(zao)聲小(xiao),不存(cun)在(zai)(zai)因電刷而引(yin)起(qi)的(de)一系列問題,所(suo)以(yi)這種電動機在(zai)(zai)控制系統中有很大的(de)應用潛力。
2、步進電動機
所謂步(bu)(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)(dong)機就(jiu)是(shi)一(yi)(yi)種將電(dian)脈(mo)沖(chong)轉化為角(jiao)(jiao)位移的(de)(de)(de)(de)執行機構。更(geng)通(tong)俗一(yi)(yi)點講:當步(bu)(bu)進(jin)(jin)驅動(dong)(dong)(dong)(dong)器接(jie)收到一(yi)(yi)個(ge)(ge)脈(mo)沖(chong)信號,它就(jiu)驅動(dong)(dong)(dong)(dong)步(bu)(bu)進(jin)(jin)電(dian)機按(an)設(she)定(ding)的(de)(de)(de)(de)方向轉動(dong)(dong)(dong)(dong)一(yi)(yi)個(ge)(ge)固定(ding)的(de)(de)(de)(de)角(jiao)(jiao)度(du)。我們可(ke)以通(tong)過控(kong)(kong)制(zhi)(zhi)脈(mo)沖(chong)的(de)(de)(de)(de)個(ge)(ge)數來控(kong)(kong)制(zhi)(zhi)電(dian)機的(de)(de)(de)(de)角(jiao)(jiao)位移量,從而(er)達到精(jing)確定(ding)位的(de)(de)(de)(de)目(mu)(mu)的(de)(de)(de)(de)。同時(shi)還可(ke)以通(tong)過控(kong)(kong)制(zhi)(zhi)脈(mo)沖(chong)頻(pin)率(lv)來控(kong)(kong)制(zhi)(zhi)電(dian)動(dong)(dong)(dong)(dong)機轉動(dong)(dong)(dong)(dong)的(de)(de)(de)(de)速(su)度(du)和加速(su)度(du),從而(er)達到調速(su)的(de)(de)(de)(de)目(mu)(mu)的(de)(de)(de)(de)。目(mu)(mu)前,比較常用的(de)(de)(de)(de)步(bu)(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)(dong)機包括反應式(shi)步(bu)(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)(dong)機(VR)、永磁式(shi)步(bu)(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)(dong)機(PM)、混(hun)合式(shi)步(bu)(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)(dong)機(HB)和單相式(shi)步(bu)(bu)進(jin)(jin)電(dian)動(dong)(dong)(dong)(dong)機等(deng)。
步進電(dian)(dian)動(dong)(dong)(dong)機(ji)和(he)(he)普通電(dian)(dian)動(dong)(dong)(dong)機(ji)的(de)(de)(de)區別主要(yao)(yao)就(jiu)在(zai)于(yu)其脈沖(chong)驅動(dong)(dong)(dong)的(de)(de)(de)形式(shi),正是(shi)這(zhe)個特(te)點,步進電(dian)(dian)動(dong)(dong)(dong)機(ji)可以和(he)(he)現代的(de)(de)(de)數(shu)(shu)字控(kong)制技術相結合。但步進電(dian)(dian)動(dong)(dong)(dong)機(ji)在(zai)控(kong)制精度(du)、速度(du)變化范圍、低速性能方面(mian)都不(bu)(bu)如傳統閉環控(kong)制的(de)(de)(de)直(zhi)流伺服電(dian)(dian)動(dong)(dong)(dong)機(ji)。所以主要(yao)(yao)應用在(zai)精度(du)要(yao)(yao)求不(bu)(bu)是(shi)特(te)別高(gao)(gao)的(de)(de)(de)場合。由于(yu)步進電(dian)(dian)動(dong)(dong)(dong)機(ji)具有結構簡單、可靠性高(gao)(gao)和(he)(he)成本低的(de)(de)(de)特(te)點,所以步進電(dian)(dian)動(dong)(dong)(dong)機(ji)廣(guang)泛應用在(zai)生(sheng)產(chan)實踐的(de)(de)(de)各個領域。尤其是(shi)在(zai)數(shu)(shu)控(kong)機(ji)床制造領域,由于(yu)步進電(dian)(dian)動(dong)(dong)(dong)機(ji)不(bu)(bu)需要(yao)(yao)A/D轉換(huan),能夠直(zhi)接(jie)將數(shu)(shu)字脈沖(chong)信號轉化成為(wei)角位(wei)移,所以一直(zhi)被認為(wei)是(shi)最(zui)理(li)想的(de)(de)(de)數(shu)(shu)控(kong)機(ji)床執(zhi)行元件(jian)。
除(chu)了在(zai)(zai)數(shu)控機(ji)(ji)床上的(de)(de)(de)應用,步進電機(ji)(ji)也可以用在(zai)(zai)其他的(de)(de)(de)機(ji)(ji)械上,比如作(zuo)為自動送料(liao)機(ji)(ji)中的(de)(de)(de)馬(ma)達,作(zuo)為通用的(de)(de)(de)軟盤驅(qu)動器(qi)的(de)(de)(de)馬(ma)達,也可以應用在(zai)(zai)打印機(ji)(ji)和繪圖儀中。
此外(wai),步進(jin)電動(dong)機(ji)也存在(zai)許多(duo)缺陷。由于步進(jin)電機(ji)存在(zai)空載啟(qi)動(dong)頻率,所以(yi)步進(jin)電機(ji)可以(yi)低(di)速正常運轉,但若高于一定速度時(shi)就(jiu)無法啟(qi)動(dong),并伴有尖銳的嘯叫聲。不同廠(chang)家的細分驅(qu)動(dong)器精(jing)度可能差別很大,細分數越(yue)大精(jing)度越(yue)難控制(zhi)。并且,步進(jin)電機(ji)低(di)速轉動(dong)時(shi)有較大的振(zhen)動(dong)和噪聲。
3、伺服電動機
伺服電(dian)動(dong)機廣泛應用于各種控制(zhi)(zhi)系(xi)統中,能將輸入(ru)的電(dian)壓信號(hao)轉換為電(dian)機軸上的機械(xie)輸出量,拖動(dong)被控制(zhi)(zhi)元件,從而達(da)到控制(zhi)(zhi)目的。
伺服電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)有直(zhi)流和(he)交流之分(fen)。最(zui)早的(de)(de)伺服電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)是一般的(de)(de)直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji),在控制(zhi)精度(du)不(bu)高的(de)(de)情況下,才采(cai)用一般的(de)(de)直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)做伺服電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)。目前的(de)(de)直(zhi)流伺服電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji)從結(jie)構上(shang)講,就(jiu)是小功率的(de)(de)直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)(ji),其勵磁(ci)多采(cai)用電(dian)(dian)(dian)(dian)(dian)(dian)樞控制(zhi)和(he)磁(ci)場控制(zhi),但通常采(cai)用電(dian)(dian)(dian)(dian)(dian)(dian)樞控制(zhi)。
旋轉電(dian)(dian)機(ji)(ji)的分類(lei),直流(liu)伺服電(dian)(dian)動(dong)(dong)機(ji)(ji)在機(ji)(ji)械(xie)特性上(shang)能夠(gou)很好(hao)的滿足控(kong)制(zhi)系統的要(yao)求,但是由于換向器的存在,存在許多的不(bu)(bu)足:換向器與電(dian)(dian)刷(shua)之間(jian)易產生火花,干擾驅動(dong)(dong)器工作(zuo),不(bu)(bu)能應用在有可燃氣(qi)體(ti)的場合(he)。電(dian)(dian)刷(shua)和(he)換向器存在摩擦,會產生較(jiao)大的死區。結構復雜,維護比較(jiao)困難。
交流(liu)伺服(fu)電(dian)動機(ji)本質上(shang)是一種兩相異步(bu)電(dian)動機(ji),其(qi)控(kong)(kong)制(zhi)(zhi)(zhi)方法主要有三種:幅值控(kong)(kong)制(zhi)(zhi)(zhi)、相位控(kong)(kong)制(zhi)(zhi)(zhi)和幅相控(kong)(kong)制(zhi)(zhi)(zhi)。
一般地,伺(si)服(fu)電(dian)動(dong)機(ji)要求電(dian)動(dong)機(ji)的(de)轉速要受所加電(dian)壓(ya)信號的(de)控制(zhi)。轉速能夠隨著(zhu)所加電(dian)壓(ya)信號的(de)變化(hua)而連續變化(hua)。電(dian)動(dong)機(ji)的(de)反(fan)映要快、體積要小、控制(zhi)功率要小。伺(si)服(fu)電(dian)動(dong)機(ji)主要應用在各種運動(dong)控制(zhi)系(xi)統中,尤其是(shi)隨動(dong)系(xi)統。
4、力矩電動機
所謂的力(li)矩(ju)(ju)電動(dong)(dong)機(ji)是(shi)一種(zhong)扁平型(xing)多(duo)極永(yong)磁直流(liu)(liu)電動(dong)(dong)機(ji)。其電樞有較多(duo)的槽數(shu)、換(huan)向片數(shu)和(he)串聯導體數(shu),以降低轉(zhuan)矩(ju)(ju)脈動(dong)(dong)和(he)轉(zhuan)速脈動(dong)(dong)。力(li)矩(ju)(ju)電動(dong)(dong)機(ji)有直流(liu)(liu)力(li)矩(ju)(ju)電動(dong)(dong)機(ji)和(he)交流(liu)(liu)力(li)矩(ju)(ju)電動(dong)(dong)機(ji)兩種(zhong)。
其中,直流力矩(ju)電動機的(de)自感(gan)電抗很(hen)小,所(suo)以(yi)響應性很(hen)好(hao)。其輸出力矩(ju)與(yu)輸入(ru)電流成(cheng)正比,與(yu)轉(zhuan)(zhuan)子(zi)的(de)速度和位(wei)置無關。它可以(yi)在(zai)接(jie)近堵(du)轉(zhuan)(zhuan)狀態下直接(jie)和負載連(lian)接(jie)低速運(yun)行而(er)(er)不用齒輪(lun)減速,所(suo)以(yi)在(zai)負載的(de)軸上能(neng)產生很(hen)高(gao)的(de)力矩(ju)對慣(guan)性比,并(bing)能(neng)消除由于使用減速齒輪(lun)而(er)(er)產生的(de)系統誤差。
交(jiao)流力矩(ju)電(dian)動(dong)機(ji)又(you)可以(yi)分為同步(bu)和異步(bu)兩(liang)種,目前常(chang)(chang)用的(de)是鼠(shu)籠(long)型異步(bu)力矩(ju)電(dian)動(dong)機(ji),它(ta)具有(you)低(di)轉(zhuan)速和大力矩(ju)的(de)特(te)點(dian)。一般(ban)地,在(zai)紡織(zhi)工(gong)業(ye)中經常(chang)(chang)使用交(jiao)流力矩(ju)電(dian)動(dong)機(ji),其工(gong)作原理和結(jie)構和單(dan)相異步(bu)電(dian)動(dong)機(ji)的(de)相同,但是由于鼠(shu)籠(long)型轉(zhuan)子的(de)電(dian)阻較(jiao)大,所以(yi)其機(ji)械特(te)性較(jiao)軟(ruan)。