1，什么是軟起動器?它與變頻器有什么區別?

　　軟起動(dong)(dong)器是(shi)一(yi)種(zhong)集電(dian)(dian)(dian)機(ji)(ji)起動(dong)(dong)、軟停車(che)、輕載節(jie)能和多種(zhong)保護(hu)功能于一(yi)體(ti)的(de)新穎電(dian)(dian)(dian)機(ji)(ji)控(kong)(kong)制裝置，稱(cheng)為(wei) SOFT STARTER。它的(de)主(zhu)要構成是(shi)串接于電(dian)(dian)(dian)源與被控(kong)(kong)電(dian)(dian)(dian)機(ji)(ji)之間的(de)三相反(fan)并(bing)(bing)聯晶閘(zha)管及其電(dian)(dian)(dian)子控(kong)(kong)制電(dian)(dian)(dian)路。運用(yong)不同(tong)的(de)方法，控(kong)(kong)制三相反(fan)并(bing)(bing)聯晶閘(zha)管的(de)導通(tong)角(jiao)，使被控(kong)(kong)電(dian)(dian)(dian)機(ji)(ji)的(de)輸(shu)入電(dian)(dian)(dian)壓(ya)按不同(tong)的(de)要求而(er)(er)變(bian)化，就可實現不同(tong)的(de)功能。軟起動(dong)(dong)器和變(bian)頻器是(shi)兩種(zhong) 不同(tong)用(yong)途的(de)產品(pin)。變(bian)頻器是(shi)用(yong)于需要調(diao)速的(de)地(di)方，其輸(shu)出不但改(gai)(gai)變(bian)電(dian)(dian)(dian)壓(ya)而(er)(er)且同(tong)時(shi)改(gai)(gai)變(bian)頻率(lv)，起動(dong)(dong)器實際上是(shi)個調(diao)壓(ya)器，用(yong)于電(dian)(dian)(dian)機(ji)(ji)起動(dong)(dong)時(shi)，輸(shu)出只改(gai)(gai)變(bian)電(dian)(dian)(dian)壓(ya)并(bing)(bing)沒有改(gai)(gai)變(bian)功率(lv)。變(bian)頻器具備備所有軟起動(dong)(dong)器功能，但它的(de)價格比軟起動(dong)(dong)器貴得多，結構也復雜(za)得多。

　　2，軟(ruan)起動與傳統減壓(ya)起動方(fang)式的不同之(zhi)處在哪里?

　　籠(long)型電機傳(chuan)統的減(jian)(jian)壓(ya)起(qi)動方(fang)(fang)式有V-起(qi)動，自耦減(jian)(jian)壓(ya)起(qi)動、電抗器(qi)起(qi)動等。這些起(qi)動方(fang)(fang)式都屬(shu)于有級(ji)減(jian)(jian)壓(ya)起(qi)動，存在明顯缺點，即起(qi)動過程中(zhong)出現二次沖擊電流。軟起(qi)動與(yu)傳(chuan)統減(jian)(jian)壓(ya)起(qi)動方(fang)(fang)式的不同之處是:

　　(1)無沖擊電流:軟起(qi)動器在起(qi)動電機(ji)時，通過逐漸 晶閘管的導通角，使電機(ji)起(qi)動電流從(cong)零線性(xing)上升至設定值。

　　(2)恒流起(qi)動:軟起(qi)動器可(ke)以引(yin)入電(dian)流閉環控制，使(shi)電(dian)機(ji)在起(qi)動過程中保持恒流，確保電(dian)機(ji)平穩起(qi)動。

　　(3)根據負載情(qing)況及電網繼電保(bao)護特(te)性(xing)選擇，可自由地無級調至理想的起動電流。

　　3、什么(me)是電動(dong)(dong)機的軟起動(dong)(dong)?有哪幾種起動(dong)(dong)方式?

　　運用串(chuan)接于(yu)電(dian)(dian)(dian)(dian)源與被控(kong)電(dian)(dian)(dian)(dian)機(ji)之間的軟(ruan)起(qi)(qi)動器，控(kong)制其(qi)內部晶閘(zha)管導通角，使(shi)電(dian)(dian)(dian)(dian)機(ji)入電(dian)(dian)(dian)(dian)壓從零以預(yu)設函數關系(xi)逐新上升，直至起(qi)(qi)動結束，予電(dian)(dian)(dian)(dian)機(ji)全電(dian)(dian)(dian)(dian)壓，即為軟(ruan)起(qi)(qi)動，在(zai)軟(ruan)起(qi)(qi)動過(guo)程中，電(dian)(dian)(dian)(dian)機(ji)起(qi)(qi)動轉矩逐漸不斷(duan)斷(duan)增加，轉速也逐浙増(zeng)加。軟(ruan)起(qi)(qi)動一般有(you)下面幾種起(qi)(qi)動方式(shi)：

　　(1)斜(xie)坡升(sheng)壓軟起動(dong):這種(zhong)起動(dong)方式簡(jian)單，不具備電流閉(bi)環控制，僅調晶閘(zha)管的(de)導(dao)通角(jiao)，使之與時間成 函數關系増加。其(qi)缺點是：由于不限流，在電機起動(dong)過程中(zhong)，有(you)時要產生較大(da)(da)的(de)沖擊電流使晶閘(zha)管損壞，對電網影響較大(da)(da)，實際很少應用。

　　(2)斜坡恒流軟起(qi)(qi)動(dong)(dong)(dong)(dong):這種(zhong)起(qi)(qi)動(dong)(dong)(dong)(dong)方式是(shi)在電動(dong)(dong)(dong)(dong)機起(qi)(qi)動(dong)(dong)(dong)(dong)的初始階段起(qi)(qi)動(dong)(dong)(dong)(dong)電流逐漸増加(jia)，當電流達到預先所(suo)設定(ding)(ding)的值后保持(chi)恒定(ding)(ding)，直至(zhi)起(qi)(qi)動(dong)(dong)(dong)(dong)完畢(bi)，起(qi)(qi)動(dong)(dong)(dong)(dong)過程中，電流上(shang)升變(bian)化的速(su)度(du)是(shi)可以根據電動(dong)(dong)(dong)(dong)機負(fu)載調整設定(ding)(ding)。電流上(shang)升速(su)本大(da)，則起(qi)(qi)動(dong)(dong)(dong)(dong)轉矩大(da)，起(qi)(qi)動(dong)(dong)(dong)(dong)時間短。該起(qi)(qi)動(dong)(dong)(dong)(dong)方式是(shi)應(ying)用(yong)很多的起(qi)(qi)動(dong)(dong)(dong)(dong)方式，尤其適用(yong)于風機、水泵類(lei)負(fu)載起(qi)(qi)動(dong)(dong)(dong)(dong)。

　　(3)階(jie)躍起動(dong):開(kai)機，即以(yi)時間短，使(shi)起動(dong)電流迅速(su)達到(dao)沒定(ding)值，即為階(jie)躍起動(dong)。通過調節起動(dong)電流設定(ding)值，可以(yi)達到(dao)快速(su)起動(dong)效果(guo)。

　　(4)脈沖沖擊起(qi)動:在起(qi)動開始階，讓晶閘管(guan)在極(ji)短時間內，以較大電流導通(tong)一(yi)時間后回落，再(zai)按(an)原設定值線性上(shang)升，連入(ru)恒(heng)流起(qi)動。該(gai)起(qi)動方式，在一(yi)般(ban)負中蛟(jiao)少應用(yong)，適用(yong)于重載并需克服較大靜摩擦的起(qi)動場合。