XL-21型動(dong)力柜，也(ye)稱箱力（XL）系列(lie)動(dong)力柜，是我國新中國成(cheng)立以后出現(xian)的最(zui)早、應用最(zui)廣的動(dong)力柜。

配(pei)電(dian)(dian)(dian)(dian)箱(xiang)(xiang)分動(dong)力配(pei)電(dian)(dian)(dian)(dian)箱(xiang)(xiang)和照明配(pei)電(dian)(dian)(dian)(dian)箱(xiang)(xiang)，是(shi)配(pei)電(dian)(dian)(dian)(dian)系統的末級設備(bei)。配(pei)電(dian)(dian)(dian)(dian)箱(xiang)(xiang)是(shi)按電(dian)(dian)(dian)(dian)氣接(jie)線(xian)要(yao)求將開(kai)關設備(bei)、測(ce)量儀表、保護(hu)電(dian)(dian)(dian)(dian)器和輔助(zhu)設備(bei)組裝在封閉(bi)或(huo)(huo)(huo)半封閉(bi)金屬(shu)柜中(zhong)(zhong)或(huo)(huo)(huo)屏幅上，構成低壓配(pei)電(dian)(dian)(dian)(dian)裝置(zhi)。正常(chang)運行時可借助(zhu)手動(dong)或(huo)(huo)(huo)自動(dong)開(kai)關接(jie)通或(huo)(huo)(huo)分斷電(dian)(dian)(dian)(dian)路。故(gu)障或(huo)(huo)(huo)不(bu)正常(chang)運行時借助(zhu)保護(hu)電(dian)(dian)(dian)(dian)器切斷電(dian)(dian)(dian)(dian)路或(huo)(huo)(huo)報警。借測(ce)量儀表可顯示運行中(zhong)(zhong)的各種參數(shu)，還可對(dui)某(mou)些電(dian)(dian)(dian)(dian)氣參數(shu)進(jin)行調整，對(dui)偏離正常(chang)工作狀態(tai)進(jin)行提示或(huo)(huo)(huo)是(shi)發出信(xin)號。常(chang)用于各發、配(pei)、變(bian)電(dian)(dian)(dian)(dian)所中(zhong)(zhong)。

XL-21型系列低壓(ya)動(dong)(dong)(dong)力(li)配(pei)電(dian)(dian)(dian)(dian)柜(ju)(ju)適合(he)于(yu)工業(ye)與民用(yong)建筑中(zhong)作交流頻率為50/60HZ、電(dian)(dian)(dian)(dian)壓(ya)500V及以(yi)下(xia)、三(san)相四線(xian)電(dian)(dian)(dian)(dian)力(li)系統(tong)的動(dong)(dong)(dong)力(li)配(pei)電(dian)(dian)(dian)(dian)和照明(ming)配(pei)電(dian)(dian)(dian)(dian)用(yong)。同時適合(he)制作各種(zhong)電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)啟(qi)(qi)動(dong)(dong)(dong)柜(ju)(ju)，包(bao)括全壓(ya)直(zhi)接啟(qi)(qi)動(dong)(dong)(dong)柜(ju)(ju)，全數字控制軟啟(qi)(qi)動(dong)(dong)(dong)柜(ju)(ju)、自(zi)耦降壓(ya)啟(qi)(qi)動(dong)(dong)(dong)柜(ju)(ju)，星三(san)角啟(qi)(qi)動(dong)(dong)(dong)柜(ju)(ju)，多速電(dian)(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)啟(qi)(qi)動(dong)(dong)(dong)柜(ju)(ju)等。具有數十種(zhong)一次線(xian)路方案號(hao)或(huo)派生方案號(hao)供選擇使用(yong)，適用(yong)范(fan)圍廣。

本(ben)產(chan)品系(xi)戶(hu)內(nei)封(feng)閉式(shi)配(pei)電(dian)(dian)(dian)箱(xiang)。箱(xiang)體用(yong)薄鋼(gang)板(ban)彎制焊接(jie)而(er)成，正面為單扇左開門(men)，門(men)上裝有電(dian)(dian)(dian)壓(ya)表(biao)、電(dian)(dian)(dian)流表(biao)等測量儀表(biao)和(he)操作電(dian)(dian)(dian)器(qi)、信號電(dian)(dian)(dian)器(qi)等，是一種結構簡單、運行(xing)可(ke)靠、成本(ben)較低的(de)動力配(pei)電(dian)(dian)(dian)裝置。