冷庫壓縮機常見的故障及處理方法

一、電機燒毀

電動機壓縮機（以(yi)下(xia)簡稱壓縮機(ji)）的故(gu)(gu)障(zhang)可分(fen)為電機(ji)故(gu)(gu)障(zhang)和(he)機(ji)械(xie)故(gu)(gu)障(zhang)（包括曲軸，連桿，活塞，閥片，缸蓋(gai)墊等）。

機械故(gu)障往往使(shi)電(dian)機超負(fu)荷(he)運轉(zhuan)甚(shen)至(zhi)堵轉(zhuan)，是電(dian)機損壞的(de)主要(yao)原(yuan)因之一(yi)。

電機的(de)(de)損(sun)壞主要(yao)表(biao)現為(wei)定(ding)子繞(rao)(rao)組(zu)絕緣(yuan)層破(po)壞（短(duan)路）和斷路等(deng)。定(ding)子繞(rao)(rao)組(zu)損(sun)壞后(hou)很(hen)難及時被發(fa)現，最終(zhong)可能導(dao)致繞(rao)(rao)組(zu)燒(shao)(shao)毀(hui)。繞(rao)(rao)組(zu)燒(shao)(shao)毀(hui)后(hou)，掩蓋了一些(xie)導(dao)致燒(shao)(shao)毀(hui)的(de)(de)現象或直接(jie)原因，使得事后(hou)分析和原因調查比(bi)較(jiao)困(kun)難。然而，電機的(de)(de)運(yun)轉離不開(kai)正常(chang)的(de)(de)電源輸入，合理(li)的(de)(de)電機負(fu)荷，良好(hao)的(de)(de)散熱(re)和繞(rao)(rao)組(zu)漆(qi)包線絕緣(yuan)層的(de)(de)保護。

從這幾方面入手，不難發現繞組燒(shao)毀(hui)的原因(yin)不外乎(hu)如下六種：

(1)異常負荷(he)和堵(du)轉；

(2)金屬屑(xie)引起的繞(rao)組短路；

(3)接觸器問題；

(4)電源(yuan)缺相和(he)電壓異常；

(5)冷卻(que)不足；

(6)用壓(ya)縮機(ji)抽真空。

實際(ji)上，多種因(yin)素共同促成(cheng)的電機損壞更為(wei)常見。

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二、異常負荷和堵轉

電機(ji)負荷包(bao)括(kuo)壓(ya)縮(suo)氣體所需負荷以及(ji)克服機(ji)械(xie)摩(mo)擦所需負荷。

壓比過大，或壓差過大，會使壓縮過程更為困難；而潤滑失效引起的摩擦阻力增加，以及極端情況下的電機堵轉，將大大增加電機負荷。潤滑失效，摩擦阻力增大，是負荷異常的首要原因。回液稀釋潤滑油，潤(run)滑(hua)油(you)(you)過熱，潤(run)滑(hua)油(you)(you)焦(jiao)(jiao)化變質，以及缺(que)油(you)(you)等(deng)都(dou)會(hui)破壞正(zheng)(zheng)常潤(run)滑(hua)，導致潤(run)滑(hua)失效(xiao)。回液稀釋潤(run)滑(hua)油(you)(you)，影響(xiang)摩(mo)擦面正(zheng)(zheng)常油(you)(you)膜(mo)的形(xing)成，甚至沖(chong)刷掉(diao)原(yuan)有(you)油(you)(you)膜(mo)，增加摩(mo)擦和磨(mo)損(sun)。壓(ya)縮機過熱會(hui)引(yin)起使(shi)潤(run)滑(hua)油(you)(you)高溫變稀甚至焦(jiao)(jiao)化，影響(xiang)正(zheng)(zheng)常油(you)(you)膜(mo)的形(xing)成。系統回油(you)(you)不好，壓(ya)縮機缺(que)油(you)(you)，自然(ran)無(wu)法維持正(zheng)(zheng)常潤(run)滑(hua)。曲軸(zhou)高速(su)(su)旋(xuan)轉(zhuan)，連桿(gan)活塞等(deng)高速(su)(su)運(yun)動，沒有(you)油(you)(you)膜(mo)保護的摩(mo)擦面會(hui)迅(xun)速(su)(su)升溫，局(ju)部(bu)高溫使(shi)潤(run)滑(hua)油(you)(you)迅(xun)速(su)(su)蒸發或(huo)焦(jiao)(jiao)化，使(shi)該部(bu)位潤(run)滑(hua)更加困難，數秒鐘內可引(yin)起局(ju)部(bu)嚴(yan)重(zhong)磨(mo)損(sun)。潤(run)滑(hua)失效(xiao)，局(ju)部(bu)磨(mo)損(sun)，使(shi)曲軸(zhou)轉(zhuan)動需要更大力矩。

小(xiao)功(gong)率(lv)壓(ya)(ya)縮(suo)機(ji)（如冰箱，家用(yong)空調壓(ya)(ya)縮(suo)機(ji)）由(you)于電(dian)(dian)(dian)(dian)(dian)機(ji)扭矩(ju)小(xiao)，潤滑(hua)失效后常出現堵(du)轉(zhuan)（電(dian)(dian)(dian)(dian)(dian)機(ji)無法轉(zhuan)動(dong)）現象，并進入“堵(du)轉(zhuan)－熱(re)(re)保護(hu)－堵(du)轉(zhuan)”死循環(huan)，電(dian)(dian)(dian)(dian)(dian)機(ji)燒(shao)毀只(zhi)是時間問(wen)題。而大(da)功(gong)率(lv)半封閉壓(ya)(ya)縮(suo)機(ji)電(dian)(dian)(dian)(dian)(dian)機(ji)扭矩(ju)很(hen)大(da)，局部磨損不(bu)會(hui)引起(qi)堵(du)轉(zhuan)，電(dian)(dian)(dian)(dian)(dian)機(ji)功(gong)率(lv)會(hui)在(zai)一(yi)定范(fan)圍內隨負(fu)荷(he)而增(zeng)大(da)，從(cong)而引起(qi)更為嚴重(zhong)的(de)(de)(de)磨損，甚至(zhi)引起(qi)咬缸（活(huo)塞卡(ka)在(zai)氣(qi)缸內），連桿(gan)斷裂等(deng)(deng)嚴重(zhong)損壞(huai)。堵(du)轉(zhuan)時的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)（堵(du)轉(zhuan)電(dian)(dian)(dian)(dian)(dian)流(liu)）大(da)約是正常運行電(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)4－8倍。電(dian)(dian)(dian)(dian)(dian)機(ji)啟(qi)(qi)動(dong)瞬間，電(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)峰值可(ke)接近或(huo)達(da)到堵(du)轉(zhuan)電(dian)(dian)(dian)(dian)(dian)流(liu)。由(you)于電(dian)(dian)(dian)(dian)(dian)阻(zu)放熱(re)(re)量與電(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)平(ping)方(fang)成(cheng)正比，啟(qi)(qi)動(dong)和堵(du)轉(zhuan)時的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)會(hui)使(shi)繞(rao)組(zu)迅速升(sheng)溫。熱(re)(re)保護(hu)可(ke)以在(zai)堵(du)轉(zhuan)時保護(hu)電(dian)(dian)(dian)(dian)(dian)極，但一(yi)般不(bu)會(hui)有很(hen)快的(de)(de)(de)響應，不(bu)能(neng)阻(zu)止頻(pin)繁(fan)(fan)啟(qi)(qi)動(dong)等(deng)(deng)引起(qi)的(de)(de)(de)繞(rao)組(zu)溫度(du)變化。頻(pin)繁(fan)(fan)啟(qi)(qi)動(dong)和異常負(fu)荷(he)，使(shi)繞(rao)組(zu)經受高溫考驗，會(hui)降(jiang)低漆(qi)包線(xian)的(de)(de)(de)絕緣性能(neng)。此外，壓(ya)(ya)縮(suo)氣(qi)體所(suo)需負(fu)荷(he)也會(hui)隨壓(ya)(ya)縮(suo)比增(zeng)大(da)和壓(ya)(ya)差增(zeng)大(da)而增(zeng)大(da)。

因此將(jiang)高溫壓(ya)縮(suo)機(ji)用于低(di)溫，或將(jiang)低(di)溫壓(ya)縮(suo)機(ji)用于高溫，都(dou)會影響電(dian)機(ji)負荷和散熱，是不合適的，會縮(suo)短電(dian)極使用壽命。繞組絕緣性能變差后，如果有其它因素(su)（如金屬屑構成導電(dian)回路，酸性潤滑(hua)油等(deng)）配合，很容易引起短路而損壞。

三、金屬屑引起的繞組短路

繞組中夾雜的金屬屑是短(duan)路和接地絕(jue)緣值低的罪魁禍首。

壓縮機運轉時的(de)正常振動(dong)(dong)，以(yi)及每次啟動(dong)(dong)時繞(rao)組(zu)受電磁力作用而扭動(dong)(dong)，都會促使(shi)夾雜(za)于(yu)繞(rao)組(zu)間的(de)金(jin)屬(shu)(shu)屑(xie)(xie)與繞(rao)組(zu)漆包線之間的(de)相對(dui)運動(dong)(dong)和摩(mo)擦。棱角銳利的(de)金(jin)屬(shu)(shu)屑(xie)(xie)會劃傷漆包線絕緣層(ceng)，引起短(duan)路。金(jin)屬(shu)(shu)屑(xie)(xie)的(de)來源包括施(shi)工(gong)時留下(xia)(xia)的(de)銅(tong)管(guan)(guan)屑(xie)(xie)，焊渣，壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)內(nei)部磨損(sun)和零部件損(sun)壞(huai)（比如(ru)(ru)(ru)閥片破碎(sui)）時掉下(xia)(xia)的(de)金(jin)屬(shu)(shu)屑(xie)(xie)等(deng)。對(dui)于(yu)全(quan)封閉(bi)壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)（包括全(quan)封閉(bi)渦(wo)旋壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)），這些金(jin)屬(shu)(shu)屑(xie)(xie)或碎(sui)粒(li)會落在(zai)(zai)繞(rao)組(zu)上(shang)。對(dui)于(yu)半封閉(bi)壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)，有(you)(you)些顆粒(li)會隨氣(qi)體和潤滑油在(zai)(zai)系統中(zhong)流動(dong)(dong)，最后由于(yu)磁性聚集(ji)在(zai)(zai)繞(rao)組(zu)中(zhong)；而有(you)(you)些金(jin)屬(shu)(shu)屑(xie)(xie)（比如(ru)(ru)(ru)軸承磨損(sun)以(yi)及電機(ji)(ji)(ji)轉子(zi)與定(ding)子(zi)磨損(sun)（掃膛）時產生的(de)）會直接落在(zai)(zai)繞(rao)組(zu)上(shang)。繞(rao)組(zu)中(zhong)聚集(ji)了(le)金(jin)屬(shu)(shu)屑(xie)(xie)后，發生短(duan)路只是一個(ge)時間問題。需要特別提請注意(yi)的(de)是雙(shuang)級壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)。在(zai)(zai)雙(shuang)級壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)中(zhong)，回(hui)(hui)氣(qi)以(yi)及正常的(de)回(hui)(hui)油直接進(jin)(jin)入(ru)第一級（低壓(ya)(ya)級）氣(qi)缸，壓(ya)(ya)縮(suo)(suo)后經中(zhong)壓(ya)(ya)管(guan)(guan)進(jin)(jin)入(ru)電機(ji)(ji)(ji)腔冷(leng)卻繞(rao)組(zu)，然后和普通單級壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)一樣，進(jin)(jin)入(ru)第二級（高壓(ya)(ya)級氣(qi)缸）。回(hui)(hui)氣(qi)中(zhong)帶有(you)(you)潤滑油，已經使(shi)壓(ya)(ya)縮(suo)(suo)過程(cheng)如(ru)(ru)(ru)履薄冰，如(ru)(ru)(ru)果再(zai)有(you)(you)回(hui)(hui)液(ye)，第一級氣(qi)缸的(de)閥片很容易(yi)被打碎(sui)。碎(sui)閥片經中(zhong)壓(ya)(ya)管(guan)(guan)后可進(jin)(jin)入(ru)繞(rao)組(zu)。因此，雙(shuang)級壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)比單級壓(ya)(ya)縮(suo)(suo)機(ji)(ji)(ji)更(geng)容易(yi)出現金(jin)屬(shu)(shu)屑(xie)(xie)引起的(de)電機(ji)(ji)(ji)短(duan)路。

不(bu)幸(xing)的事情往往湊到(dao)一塊，出問題的壓縮機(ji)(ji)在(zai)開機(ji)(ji)分析時(shi)聞道的常常是(shi)潤滑(hua)油的焦糊(hu)味。金屬(shu)面嚴重磨損時(shi)溫度是(shi)很高的，而潤滑(hua)油在(zai)175?C以上時(shi)開始焦化。系統中如果有較多(duo)水(shui)分（真空(kong)(kong)抽得不(bu)理想(xiang)，潤滑(hua)油和(he)制冷劑含(han)水(shui)量大，負壓回氣(qi)管破裂(lie)后空(kong)(kong)氣(qi)進(jin)入等），潤滑(hua)油就可能(neng)出現酸(suan)性(xing)。酸(suan)性(xing)潤滑(hua)油會(hui)腐蝕銅管和(he)繞(rao)組絕(jue)緣(yuan)層(ceng)，一方面，它會(hui)引起鍍銅現象；另一方面，這種含(han)有銅原(yuan)子的酸(suan)性(xing)潤滑(hua)油的絕(jue)緣(yuan)性(xing)能(neng)很差，為(wei)繞(rao)組短路提供了條件。

四、接觸器問題

接觸器是電機(ji)控制回路(lu)中重(zhong)要部(bu)件之一，選型不合理可(ke)以毀壞最好的(de)壓縮機(ji)。

按負(fu)載(zai)正(zheng)確選(xuan)擇(ze)接(jie)觸器(qi)是(shi)極其重(zhong)要的(de)。接(jie)觸器(qi)必(bi)(bi)須能滿足苛刻的(de)條件，如(ru)快速循環，持續(xu)超載(zai)和(he)低電(dian)壓。它們必(bi)(bi)須有足夠大(da)的(de)面積以(yi)散發負(fu)載(zai)電(dian)流(liu)所產生(sheng)的(de)熱量，觸點材料的(de)選(xuan)擇(ze)必(bi)(bi)須在(zai)啟動或(huo)堵轉等大(da)電(dian)流(liu)情況下能防止焊(han)合。為了安全(quan)可(ke)靠，壓縮機接(jie)觸器(qi)要同時斷開三相(xiang)電(dian)路。谷(gu)輪公(gong)司不(bu)推薦斷開二(er)相(xiang)電(dian)路的(de)方法。在(zai)美(mei)國，谷(gu)輪公(gong)司認(ren)可(ke)的(de)接(jie)觸器(qi)必(bi)(bi)須滿足如(ru)下四項：

接觸(chu)器必(bi)須(xu)滿足(zu)ARI標(biao)準780-78“專用接觸(chu)器標(biao)準”規定的工作和測試(shi)準則(ze)。

制造(zao)商(shang)必須(xu)保證接觸器(qi)在室(shi)溫下(xia)，在最低銘牌電壓的80％時能閉合。

當使(shi)用(yong)單個接(jie)觸(chu)(chu)(chu)器(qi)時，接(jie)觸(chu)(chu)(chu)器(qi)額(e)定電(dian)(dian)流(liu)必須大于電(dian)(dian)機銘牌電(dian)(dian)流(liu)額(e)定值(zhi)(RLA).同(tong)時，接(jie)觸(chu)(chu)(chu)器(qi)必須能承受電(dian)(dian)機堵轉電(dian)(dian)流(liu)。如(ru)(ru)果(guo)接(jie)觸(chu)(chu)(chu)器(qi)下游(you)還有其它負載(zai)，比(bi)如(ru)(ru)電(dian)(dian)機風扇等，也必須考慮。

當使用兩個(ge)接觸(chu)器(qi)時，每個(ge)接觸(chu)器(qi)的分繞組(zu)堵轉額定值(zhi)必須等(deng)于(yu)或大(da)于(yu)壓縮機半繞組(zu)堵轉額定值(zhi)。

接觸(chu)器的(de)額定(ding)電(dian)流(liu)不能(neng)低于壓縮機銘牌上的(de)額定(ding)電(dian)流(liu)。

規格小(xiao)或質量(liang)低(di)劣的(de)(de)(de)(de)接(jie)(jie)觸(chu)器無法經受壓縮機啟(qi)動(dong)，堵轉(zhuan)和低(di)電(dian)(dian)(dian)壓時的(de)(de)(de)(de)大電(dian)(dian)(dian)流(liu)沖擊(ji)，容(rong)(rong)易(yi)出(chu)現(xian)單相(xiang)或多(duo)相(xiang)觸(chu)點抖動(dong),焊接(jie)(jie)甚至脫落(luo)的(de)(de)(de)(de)現(xian)象，引(yin)起電(dian)(dian)(dian)機損壞(huai)(huai)。觸(chu)點抖動(dong)的(de)(de)(de)(de)接(jie)(jie)觸(chu)器頻繁(fan)地(di)啟(qi)停電(dian)(dian)(dian)機。電(dian)(dian)(dian)機頻繁(fan)啟(qi)動(dong)，巨大的(de)(de)(de)(de)啟(qi)動(dong)電(dian)(dian)(dian)流(liu)和發熱(re),會加劇繞(rao)(rao)組絕緣層的(de)(de)(de)(de)老化。每次(ci)啟(qi)動(dong)時，磁性力矩使電(dian)(dian)(dian)機繞(rao)(rao)組有(you)(you)微小(xiao)的(de)(de)(de)(de)移動(dong)和相(xiang)互摩擦。如(ru)果有(you)(you)其它因素配合(he)（如(ru)金屬(shu)屑，絕緣性差(cha)的(de)(de)(de)(de)潤滑油等），很容(rong)(rong)易(yi)引(yin)起繞(rao)(rao)組間短路。熱(re)保護系統并(bing)未設(she)計成能防止這種毀壞(huai)(huai)。此(ci)外，抖動(dong)的(de)(de)(de)(de)接(jie)(jie)觸(chu)器線(xian)圈容(rong)(rong)易(yi)失效。如(ru)果有(you)(you)接(jie)(jie)觸(chu)線(xian)圈損壞(huai)(huai)，容(rong)(rong)易(yi)出(chu)現(xian)單相(xiang)狀態。

如(ru)果接(jie)(jie)(jie)觸(chu)(chu)(chu)器選型偏小，觸(chu)(chu)(chu)頭不能承受(shou)電(dian)弧(hu)和由于(yu)頻繁開(kai)停循環或不穩定控(kong)(kong)制(zhi)(zhi)回路(lu)電(dian)壓(ya)產生的(de)高(gao)溫，可(ke)能焊合(he)或從觸(chu)(chu)(chu)頭架(jia)中(zhong)脫落(luo)。焊合(he)的(de)觸(chu)(chu)(chu)頭將產生永久性單相狀態，使(shi)過載(zai)保(bao)護(hu)器持(chi)續地(di)循環接(jie)(jie)(jie)通(tong)和斷開(kai)，需(xu)要特別強(qiang)調(diao)的(de)是，接(jie)(jie)(jie)觸(chu)(chu)(chu)器觸(chu)(chu)(chu)點焊合(he)后，依賴(lai)接(jie)(jie)(jie)觸(chu)(chu)(chu)器斷開(kai)壓(ya)縮機(ji)(ji)電(dian)源回路(lu)的(de)所有控(kong)(kong)制(zhi)(zhi)（比(bi)如(ru)高(gao)低壓(ya)控(kong)(kong)制(zhi)(zhi)，油壓(ya)控(kong)(kong)制(zhi)(zhi)，融霜控(kong)(kong)制(zhi)(zhi)等）將全部失效，壓(ya)縮機(ji)(ji)處(chu)于(yu)無保(bao)護(hu)狀態。

因此，當(dang)電(dian)機燒毀后，檢查接(jie)觸器(qi)是必不可(ke)少的(de)工序。接(jie)觸器(qi)是導(dao)致電(dian)機損壞(huai)的(de)一個常(chang)常(chang)被人遺忘的(de)重(zhong)要原(yuan)因。

五、電源缺相和電壓異常

電壓不正常和缺相(xiang)可以輕而易舉地毀掉任何電機。

電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)變化范圍不(bu)能(neng)超(chao)過額定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)(de)(de)±10%。三(san)(san)相(xiang)(xiang)間的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)不(bu)能(neng)超(chao)過5％。大(da)(da)功率電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)必(bi)須(xu)獨立供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，以(yi)防同線其(qi)他大(da)(da)功率設備啟(qi)動和(he)(he)運轉(zhuan)時造(zao)成低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源線必(bi)須(xu)能(neng)夠承載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)的(de)(de)(de)(de)(de)額定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。如果發(fa)生(sheng)缺相(xiang)(xiang)時壓(ya)(ya)(ya)(ya)(ya)縮(suo)機(ji)(ji)(ji)正在(zai)(zai)運轉(zhuan)，它將繼續(xu)運行(xing)但(dan)會(hui)(hui)有大(da)(da)的(de)(de)(de)(de)(de)負(fu)載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)繞組(zu)(zu)會(hui)(hui)很(hen)(hen)快過熱，正常(chang)情況下壓(ya)(ya)(ya)(ya)(ya)縮(suo)機(ji)(ji)(ji)會(hui)(hui)被熱保(bao)護(hu)(hu)。當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)繞組(zu)(zu)冷卻至設定溫度，接觸器(qi)會(hui)(hui)閉合，但(dan)壓(ya)(ya)(ya)(ya)(ya)縮(suo)機(ji)(ji)(ji)啟(qi)動不(bu)起來，出現(xian)堵(du)轉(zhuan)，并進入“堵(du)轉(zhuan)－熱保(bao)護(hu)(hu)－堵(du)轉(zhuan)”死循環。現(xian)代電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)繞組(zu)(zu)的(de)(de)(de)(de)(de)差別非(fei)常(chang)小，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源三(san)(san)相(xiang)(xiang)平衡(heng)(heng)(heng)(heng)(heng)(heng)時相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)(de)差別可以(yi)忽略。理想狀態下，相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)始終相(xiang)(xiang)等(deng)，只要在(zai)(zai)任(ren)一(yi)相(xiang)(xiang)上(shang)接一(yi)個保(bao)護(hu)(hu)器(qi)就可以(yi)防止過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)造(zao)成的(de)(de)(de)(de)(de)損壞。實際上(shang)很(hen)(hen)難保(bao)證相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)的(de)(de)(de)(de)(de)平衡(heng)(heng)(heng)(heng)(heng)(heng)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)百(bai)分(fen)數(shu)(shu)計算方法為(wei)(wei)(wei)，相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)與三(san)(san)相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)平均(jun)值(zhi)的(de)(de)(de)(de)(de)最大(da)(da)偏差值(zhi)與三(san)(san)相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)平均(jun)值(zhi)比值(zhi)。例(li)如，標稱(cheng)380V三(san)(san)相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源，在(zai)(zai)壓(ya)(ya)(ya)(ya)(ya)縮(suo)機(ji)(ji)(ji)接線端測量的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)分(fen)別為(wei)(wei)(wei)380V、366V、400V。可以(yi)計算出三(san)(san)相(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)平均(jun)值(zhi)382V，最大(da)(da)偏差為(wei)(wei)(wei)20V,所以(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)百(bai)分(fen)數(shu)(shu)為(wei)(wei)(wei)5.2％。作為(wei)(wei)(wei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)的(de)(de)(de)(de)(de)結果，在(zai)(zai)正常(chang)運行(xing)使負(fu)載(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)(de)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)是電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)百(bai)分(fen)點數(shu)(shu)的(de)(de)(de)(de)(de)4－10倍(bei)(bei)。前(qian)(qian)例(li)中，5.2％不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)可能(neng)引起50％的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)。美(mei)國(guo)國(guo)家電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)制造(zao)商協(xie)會(hui)(hui)(NEMA)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)動機(ji)(ji)(ji)和(he)(he)發(fa)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)標準出版物指(zhi)出，由不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)造(zao)成的(de)(de)(de)(de)(de)相(xiang)(xiang)繞組(zu)(zu)溫升(sheng)百(bai)分(fen)比大(da)(da)約是電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)百(bai)分(fen)點數(shu)(shu)平方的(de)(de)(de)(de)(de)兩倍(bei)(bei)。前(qian)(qian)例(li)中電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)點數(shu)(shu)為(wei)(wei)(wei)5.2，繞組(zu)(zu)溫度增(zeng)加的(de)(de)(de)(de)(de)百(bai)分(fen)數(shu)(shu)為(wei)(wei)(wei)54％。結果是一(yi)相(xiang)(xiang)繞組(zu)(zu)過熱而其(qi)他兩個繞組(zu)(zu)溫度正常(chang)。一(yi)份由U.L.(保(bao)險(xian)商實驗(yan)室，美(mei)國(guo))完(wan)成的(de)(de)(de)(de)(de)調查顯(xian)示，43％的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)公司(si)(si)允(yun)許3％的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)，另有30％的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)公司(si)(si)允(yun)許5％的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)不(bu)平衡(heng)(heng)(heng)(heng)(heng)(heng)。

六、冷卻不足

功率(lv)較大的(de)壓縮機一般都是回氣冷卻型的(de)。蒸發(fa)溫度越(yue)低，系統(tong)質(zhi)量流往往越(yue)小。

當蒸發溫度(du)很(hen)低(di)時(shi)（超(chao)過(guo)制造商的(de)規定(ding)），流量(liang)就(jiu)不(bu)足以冷(leng)(leng)(leng)(leng)卻(que)(que)電(dian)(dian)(dian)機(ji)，電(dian)(dian)(dian)機(ji)就(jiu)會(hui)在較(jiao)高(gao)溫度(du)下(xia)運轉(zhuan)。空氣冷(leng)(leng)(leng)(leng)卻(que)(que)型壓縮(suo)機(ji)（一般不(bu)超(chao)過(guo)10HP）對回氣的(de)依賴(lai)性小，但對壓縮(suo)機(ji)環(huan)境溫度(du)和冷(leng)(leng)(leng)(leng)卻(que)(que)風量(liang)有明(ming)確要求(qiu)。制冷(leng)(leng)(leng)(leng)劑大(da)量(liang)泄漏也會(hui)造成系統質量(liang)流減小，電(dian)(dian)(dian)機(ji)的(de)冷(leng)(leng)(leng)(leng)卻(que)(que)也會(hui)受到影響。一些(xie)無人看(kan)管的(de)冷(leng)(leng)(leng)(leng)庫，往往要等到制冷(leng)(leng)(leng)(leng)效(xiao)果很(hen)差時(shi)才會(hui)發現(xian)制冷(leng)(leng)(leng)(leng)劑大(da)量(liang)泄漏了。電(dian)(dian)(dian)機(ji)過(guo)熱后會(hui)出現(xian)頻繁保護，有些(xie)用(yong)戶不(bu)深入檢查原因(yin)，甚至將熱保護器短路，那是(shi)(shi)非常糟(zao)糕的(de)事情(qing)。過(guo)不(bu)了多久(jiu)，電(dian)(dian)(dian)機(ji)就(jiu)會(hui)燒掉。壓縮(suo)機(ji)都有安全運行工(gong)況范(fan)圍。安全工(gong)況主要的(de)考慮因(yin)素就(jiu)是(shi)(shi)壓縮(suo)機(ji)和電(dian)(dian)(dian)機(ji)的(de)負荷(he)與(yu)冷(leng)(leng)(leng)(leng)卻(que)(que)。由于(yu)不(bu)同(tong)(tong)溫區(qu)的(de)壓縮(suo)機(ji)的(de)價格不(bu)同(tong)(tong)，過(guo)去國內冷(leng)(leng)(leng)(leng)凍行業超(chao)范(fan)圍使用(yong)壓縮(suo)機(ji)是(shi)(shi)比較(jiao)常見的(de)。隨著專業知(zhi)識(shi)的(de)增(zeng)長和經濟條(tiao)件的(de)改善，情(qing)況已明(ming)顯(xian)改善。