軟起動是一(yi)種(zhong)集(ji)防爆電機軟起動、軟停(ting)車、輕載(zai)節能和多種(zhong)保(bao)護(hu)功能于一(yi)體(ti)的新穎電機控(kong)制裝置(zhi)。國際簡稱：Soft Starter。 　

    防爆電(dian)機傳統的(de)起(qi)(qi)(qi)動(dong)方(fang)式(shi)有全(quan)(quan)壓(ya)起(qi)(qi)(qi)動(dong)和將壓(ya)起(qi)(qi)(qi)動(dong)，軟起(qi)(qi)(qi)動(dong)是(shi)一種完全(quan)(quan)區別于(yu)全(quan)(quan)壓(ya)和降壓(ya)起(qi)(qi)(qi)動(dong)的(de)新(xin)的(de)起(qi)(qi)(qi)動(dong)方(fang)式(shi)，是(shi)電(dian)子過程控制技術。所謂軟起(qi)(qi)(qi)動(dong)，是(shi)以斜坡控制方(fang)式(shi)起(qi)(qi)(qi)動(dong)，使電(dian)動(dong)機轉速平滑，逐步提高(gao)到(dao)額定(ding)轉速。按照電(dian)動(dong)機起(qi)(qi)(qi)動(dong)電(dian)流(liu)大(da)小(xiao)進行分類，全(quan)(quan)壓(ya)和降壓(ya)起(qi)(qi)(qi)動(dong)屬于(yu)大(da)電(dian)流(liu)起(qi)(qi)(qi)動(dong)方(fang)式(shi)，軟起(qi)(qi)(qi)動(dong)屬于(yu)小(xiao)電(dian)流(liu)起(qi)(qi)(qi)動(dong)方(fang)式(shi)。

    防爆電機全壓起(qi)(qi)動(dong)，起(qi)(qi)動(dong)電流(liu)是額定電流(liu)的4-7倍，起(qi)(qi)動(dong)沖擊電流(liu)是起(qi)(qi)動(dong)電流(liu)的1.5-1.7倍；起(qi)(qi)動(dong)電流(liu)大(da)，起(qi)(qi)動(dong)轉(zhuan)矩不相(xiang)應增大(da)，Ｔs=ＫtＴn＝Ｋ(0.9-1.3)Ｔn。

    防爆電(dian)機降(jiang)壓(ya)起動(dong)(dong)，可部分減小起動(dong)(dong)電(dian)流(liu)，起動(dong)(dong)轉矩(ju)下降(jiang)到額定(ding)電(dian)壓(ya)的(de)Ｋ2倍。降(jiang)壓(ya)起動(dong)(dong)是輕載(zai)起動(dong)(dong)，有(you)起動(dong)(dong)沖擊電(dian)流(liu)、起動(dong)(dong)電(dian)流(liu)及二次沖擊電(dian)流(liu)；二次沖擊電(dian)流(liu)同樣對(dui)配電(dian)系統有(you)麻(ma)煩。

    全壓和降壓起動的(de)(de)大(da)(da)電(dian)(dian)流，致(zhi)使電(dian)(dian)動機諧(xie)波磁勢(shi)增(zeng)大(da)(da)，增(zeng)大(da)(da)后的(de)(de)諧(xie)波磁勢(shi)又加(jia)劇了附加(jia)轉(zhuan)矩(ju)，附加(jia)轉(zhuan)矩(ju)是電(dian)(dian)機起動時產生震動和噪音的(de)(de)原(yuan)因(yin)。

    全壓(ya)和降(jiang)壓(ya)起(qi)(qi)動(dong)(dong)(dong)，都(dou)要受單位(wei)時間內起(qi)(qi)動(dong)(dong)(dong)次數(shu)(shu)的限制(zhi)。電(dian)動(dong)(dong)(dong)機(ji)本(ben)身的發熱(re)主要建立在短時間大電(dian)流(liu)(liu)時。如通過6倍額定電(dian)流(liu)(liu)，溫(wen)(wen)升(sheng)為8-15℃/S；起(qi)(qi)動(dong)(dong)(dong)裝置的自(zi)耦變壓(ya)器(qi)(qi)(qi)或交(jiao)流(liu)(liu)接觸器(qi)(qi)(qi)起(qi)(qi)動(dong)(dong)(dong)引起(qi)(qi)堆積熱(re)；如交(jiao)流(liu)(liu)接觸器(qi)(qi)(qi)一般要求起(qi)(qi)動(dong)(dong)(dong)次數(shu)(shu)每分鐘不超過10次。而(er)軟(ruan)(ruan)起(qi)(qi)動(dong)(dong)(dong)器(qi)(qi)(qi)可(ke)頻繁(fan)操作(zuo)，具有(you)①電(dian)動(dong)(dong)(dong)機(ji)起(qi)(qi)動(dong)(dong)(dong)電(dian)流(liu)(liu)小，溫(wen)(wen)升(sheng)低(di)；②軟(ruan)(ruan)起(qi)(qi)動(dong)(dong)(dong)器(qi)(qi)(qi)采用(yong)的無觸點電(dian)子元件，除大功率可(ke)控硅外，工作(zuo)時溫(wen)(wen)升(sheng)很低(di)。

    此外(wai)，防爆電機軟起動(dong)器還具有多(duo)種保(bao)護功能，配合(he)硬件電路，軟件設計(ji)有過(guo)載、斷相、欠壓、過(guo)壓等保(bao)護程序(xu)，動(dong)作可靠(kao)程度(du)高。總結(jie)來看，軟起動(dong)器很好的(de)解決了全壓和降(jiang)壓起動(dong)電流過(guo)大(da)及(ji)其派(pai)生的(de)許多(duo)問題(ti)。