春天(tian)天(tian)气(qi)比较潮湿，生产(chan)现(xian)场(chang)(chang)中(zhong)，由于电机(ji)选型(xing)(xing)原(yuan)因及保管(guan)、维(wei)护不(bu)当、环(huan)境等因素致使(shi)潮气(qi)进入(ru)电动机(ji)内(nei)部形成凝露或电动机(ji)直接进水，导(dao)致电动机(ji)绝缘电阻下降，影响电动机(ji)的正(zheng)常使(shi)用及运(yun)行(xing)安全(quan)。本文主(zhu)要针(zhen)对现(xian)场(chang)(chang)受潮的鼠(shu)笼型(xing)(xing)电机(ji)在不(bu)同状况下干(gan)燥处理的方(fang)法进行(xing)分析(xi)介绍(shao)，重点介绍(shao)电流干(gan)燥法及铁(tie)损(sun)干(gan)燥法的原(yuan)理及现(xian)场(chang)(chang)应用方(fang)法。

小容量异步电动机受潮

干燥(zao)方(fang)法(fa):小(xiao)容量异步电(dian)动(dong)机拆(chai)卸、解体较为(wei)方(fang)便，可(ke)根据现场环境就(jiu)地(di)进(jin)行(xing)干燥(zao)处理或(huo)拆(chai)卸到检(jian)修间(jian)进(jin)行(xing)处理，一般可(ke)采用以下两种方(fang)法(fa)对电(dian)动(dong)机进(jin)行(xing)干燥(zao)处理。

一(yi)般(ban)小型低压异(yi)步电(dian)动(dong)机(ji)适用外部(bu)加热干燥(zao)(zao)电(dian)动(dong)机(ji)的(de)方(fang)法，操作比(bi)较简单;其原理是干燥(zao)(zao)时利用外部(bu)热源(yuan)的(de)辐射、对流(liu)、传导方(fang)式来干燥(zao)(zao)电(dian)动(dong)机(ji);一(yi)般(ban)分为两(liang)种方(fang)法:

利用(yong)(yong)灯(deng)(deng)泡(或红外线灯(deng)(deng)泡)、烘箱进行(xing)干(gan)(gan)燥，利用(yong)(yong)热风机(ji)进行(xing)干(gan)(gan)燥;使(shi)用(yong)(yong)灯(deng)(deng)泡或碘钨灯(deng)(deng)干(gan)(gan)燥时(shi)不能(neng)(neng)太(tai)靠近线圈，以防(fang)烤坏线圈，必须使(shi)用(yong)(yong)安全防(fang)护灯(deng)(deng)具，使(shi)用(yong)(yong)烤箱时(shi)温度不能(neng)(neng)超过100 ℃。

大、中型异步电动机受潮

干燥方法有(you)以下几种:

第一、电流干燥法

电流(liu)干燥(zao)法的基本原理是(shi)向电机定子(zi)(zi)绕(rao)组通(tong)入低压(ya)电流(liu)，转(zhuan)子(zi)(zi)堵转(zhuan)，利用电机本身损耗产生(sheng)的温度(du)来干燥(zao)电机，其干燥(zao)时电机定转(zhuan)子(zi)(zi)同时发热(re)，干燥(zao)速度(du)较(jiao)快，一般(ban)用于(yu)容量较(jiao)大的高低压(ya)电机;

注:计算出堵转电(dian)(dian)流(liu)每相绕组分配的最大电(dian)(dian)流(liu)，都不宜(yi)超过原额定电(dian)(dian)流(liu)的50%~60%，就可以选择电(dian)(dian)压等级来烘(hong)干。

I=U*Iq/UN

U→下降后的电压

UN→额定电压

Iq→启动(dong)电流，一(yi)般情(qing)况下为(wei)额定电流的5~8倍

方法一:直接向电(dian)(dian)机(ji)定子绕组通(tong)(tong)入低压(ya)三相(xiang)交流电(dian)(dian)源(yuan)，不需(xu)抽出电(dian)(dian)机(ji)转子，电(dian)(dian)机(ji)定转子同时干燥(zao)，现(xian)场实现(xian)方便，大电(dian)(dian)机(ji)所需(xu)电(dian)(dian)源(yuan)容量较大，可能受现(xian)场条(tiao)件限制;6 kV电(dian)(dian)机(ji)现(xian)场一般通(tong)(tong)入380 V电(dian)(dian)源(yuan)进(jin)行(xing)干燥(zao)，如(ru)(ru)电(dian)(dian)机(ji)绝缘较低可采(cai)用转子堵转的方式进(jin)行(xing)干燥(zao)，如(ru)(ru)电(dian)(dian)机(ji)绝缘大于0.5 Ω可以通(tong)(tong)入三相(xiang)交流电(dian)(dian)后让电(dian)(dian)机(ji)转动起来进(jin)行(xing)干燥(zao)(公众号:泵管家(jia))。

方法二:电(dian)(dian)(dian)(dian)(dian)机(ji)三(san)相(xiang)绕组(zu)首尾串(chuan)联(也可以(yi)一相(xiang)反串(chuan)，以(yi)减小电(dian)(dian)(dian)(dian)(dian)流(liu))，用(yong)于6个出线头(tou)的(de)电(dian)(dian)(dian)(dian)(dian)动(dong)机(ji);利用(yong)交直流(liu)电(dian)(dian)(dian)(dian)(dian)焊机(ji)或调(diao)压器调(diao)节电(dian)(dian)(dian)(dian)(dian)流(liu)通入电(dian)(dian)(dian)(dian)(dian)机(ji)定子(zi)绕组(zu)来干(gan)燥(zao)电(dian)(dian)(dian)(dian)(dian)动(dong)机(ji)，适用(yong)于现场电(dian)(dian)(dian)(dian)(dian)源容(rong)量不足时的(de)高(gao)低压电(dian)(dian)(dian)(dian)(dian)动(dong)机(ji)干(gan)燥(zao);接通、切断电(dian)(dian)(dian)(dian)(dian)焊机(ji)电(dian)(dian)(dian)(dian)(dian)流(liu)时应首先将电(dian)(dian)(dian)(dian)(dian)流(liu)调(diao)节到零，防止产(chan)生高(gao)电(dian)(dian)(dian)(dian)(dian)压损(sun)伤(shang)电(dian)(dian)(dian)(dian)(dian)机(ji)绝缘;现场处理不需抽出电(dian)(dian)(dian)(dian)(dian)机(ji)转(zhuan)子(zi)，实(shi)现方便。

方法(fa)三(san):电(dian)(dian)动(dong)(dong)机三(san)相绕组并(bing)联(lian)(lian)(用(yong)于6个出(chu)线(xian)头的电(dian)(dian)动(dong)(dong)机)或两相串联(lian)(lian)后(hou)与另一相并(bing)联(lian)(lian)(用(yong)于3个出(chu)线(xian)头电(dian)(dian)动(dong)(dong)机);利用(yong)交直流(liu)电(dian)(dian)焊机或调压器调节电(dian)(dian)流(liu)通入电(dian)(dian)机定(ding)子绕组来(lai)干燥(zao)电(dian)(dian)动(dong)(dong)机。

电流干(gan)燥法干(gan)燥电动(dong)机(ji)举例(li)

以一(yi)台(tai)型号PP400，容量3000W，电(dian)(dian)流335 A，电(dian)(dian)压6 kV的(de)电(dian)(dian)机为例:该(gai)电(dian)(dian)机为室(shi)外电(dian)(dian)机，基建期(qi)内(nei)，准备(bei)投(tou)入(ru)该(gai)电(dian)(dian)机试运行，现场测量绝(jue)缘电(dian)(dian)阻2 MΩ，天气中(zhong)雨(yu)，湿度(du)大(公(gong)众(zhong)号:泵管(guan)家)。投(tou)入(ru)电(dian)(dian)机自带加热(re)器后(hou)经过36 h后(hou)，测量其绝(jue)缘电(dian)(dian)阻3 MΩ左右变化(hua)不(bu)大，准备(bei)在原电(dian)(dian)机加热(re)继续投(tou)入(ru)的(de)情况(kuang)下，增加电(dian)(dian)机电(dian)(dian)流干燥法进行干燥。

实(shi)(shi)(shi)施方(fang)法:在电(dian)(dian)(dian)机周围搭设临时防雨(yu)棚、接(jie)入现(xian)(xian)场380 V电(dian)(dian)(dian)源进行干燥，启(qi)动电(dian)(dian)(dian)流(liu)Iq取(qu)7倍额定电(dian)(dian)(dian)流(liu)2 345 A，计算选用(yong)3+1芯35 mm2铜芯电(dian)(dian)(dian)缆、测量器具:2 500 V兆欧(ou)表一块，钳形电(dian)(dian)(dian)流(liu)表一块，红外线测温仪(yi)一块，电(dian)(dian)(dian)机的接(jie)线盒，两(liang)侧(ce)检查孔(kong)打(da)开一缝隙，利于(yu)潮气(qi)散发。经过12 h后，绝缘电(dian)(dian)(dian)阻稳定在36 MΩ左右，达(da)到干燥目的。现(xian)(xian)场实(shi)(shi)(shi)测电(dian)(dian)(dian)流(liu)146 A、通(tong)过现(xian)(xian)场实(shi)(shi)(shi)测及DCS画面监测温度，线圈(quan)温度最高85 ℃。

第二(er)、电(dian)机铁损干燥法

铁(tie)(tie)损干(gan)燥法的(de)(de)(de)基本原理是在电机定子(zi)绕组铁(tie)(tie)芯上(shang)绕制励磁(ci)(ci)线(xian)圈，通入(ru)交(jiao)流电，使定子(zi)铁(tie)(tie)芯产生(sheng)磁(ci)(ci)通，利用铁(tie)(tie)芯的(de)(de)(de)涡流损耗产生(sheng)的(de)(de)(de)温升来干(gan)燥电机。

方法一(yi):在电(dian)机(ji)定子铁芯(xin)上(shang)缠绕励(li)磁线圈(通过定子膛内)，通入380 V(220 V)交流电(dian)源(yuan)，干燥电(dian)机(ji)绝缘。适用范围:大中型电(dian)机(ji)，电(dian)机(ji)转子铁芯(xin)抽出。

方法二:在电机(ji)定子外(wai)壳上缠绕励磁线圈，通过电焊机(ji)、调压变接入电源，干(gan)燥电机(ji)绝缘(yuan)。适用范围:大中(zhong)型电机(ji)，电机(ji)现场已安装(zhuang)完毕。

其他注意事项：

①对(dui)转子抽出(chu)的(de)(de)电机，加热干(gan)(gan)燥应在(zai)清(qing)洁的(de)(de)空气中进行，干(gan)(gan)燥前将(jiang)电机的(de)(de)各部分(fen)清(qing)理干(gan)(gan)净。

②电机(ji)干燥时，电机(ji)的绕组温(wen)度必须低于其规(gui)定(ding)的绝(jue)缘等(deng)级要求的温(wen)度(为保证安全，最(zui)好低于其规(gui)定(ding)温(wen)度10℃以下)，一般(ban)干燥时绕组温(wen)度控制在70 ℃~80 ℃为最(zui)佳。

③绕组过度潮湿的电机，不能(neng)使用直(zhi)(zhi)流(liu)电流(liu)干燥法，直(zhi)(zhi)流(liu)电有电解作(zuo)用。

④使(shi)用电(dian)流、铁损(sun)法干燥时，电(dian)机外壳必须有良(liang)好接地线，以防止触电(dian)。使(shi)用灯(deng)泡(pao)或碘钨灯(deng)等烘烤时，也应注意防止触电(dian)。

⑤封闭型电(dian)(dian)(dian)机(ji)(ji)，不抽出(chu)转子干燥时，电(dian)(dian)(dian)机(ji)(ji)的(de)接线(xian)盒(he)或检查(cha)孔要打开一定(ding)缝隙，小(xiao)型低(di)压电(dian)(dian)(dian)机(ji)(ji)也可将(jiang)电(dian)(dian)(dian)机(ji)(ji)端盖打开一缝隙，以利于电(dian)(dian)(dian)机(ji)(ji)内潮气散发。

⑥在干燥过程中，定时测量绕组各(ge)部(bu)温(wen)度和绝缘(yuan)电阻，并作好(hao)记录。干燥初始阶段每15~30 min记录一次，以后1~2 h必(bi)须记录一次定时检测电机温(wen)度，防止电机某点过热造(zao)成损(sun)坏(huai)。

⑦干燥中，加热(re)温(wen)度应逐步升(sheng)(sheng)高，较潮湿的(de)电机，应缓(huan)慢加热(re)到50~60 ℃，保持3~4 h，再逐步升(sheng)(sheng)高温(wen)度。

⑧电机干燥初始阶段，由于温度的(de)升(sheng)高、潮气的(de)排放(fang)，绝(jue)缘(yuan)(yuan)电阻会下(xia)(xia)降(jiang)，然后(hou)逐渐(jian)上(shang)升(sheng)，上(shang)升(sheng)速度变慢，最后(hou)达到(dao)稳定(ding)，在(zai)恒定(ding)的(de)温度下(xia)(xia)，绝(jue)缘(yuan)(yuan)电阻值保持3~4 h以上(shang)不变时，干燥工作即可结(jie)束。

⑨对转子不抽(chou)出的电机干燥过程中(zhong)，如条件满足，定期(qi)盘(pan)动电机转子180 ℃，预防转子受热不均导致变形，也(ye)利于潮(chao)气散发。

其实(shi)，电(dian)(dian)(dian)机(ji)(ji)受潮后干(gan)燥的(de)(de)具体方(fang)法(fa)有很多，生产现场中应(ying)(ying)根据具体情况(kuang)选(xuan)用合适的(de)(de)干(gan)燥方(fang)法(fa)对(dui)电(dian)(dian)(dian)机(ji)(ji)进行(xing)干(gan)燥处理，但无论选(xuan)用何种方(fang)式干(gan)燥电(dian)(dian)(dian)机(ji)(ji)，必须注(zhu)意电(dian)(dian)(dian)机(ji)(ji)温度(du)不能(neng)超过其允许值，不能(neng)对(dui)电(dian)(dian)(dian)机(ji)(ji)绝(jue)缘(yuan)产生新的(de)(de)破坏，干(gan)燥期间(jian)注(zhu)意设备(bei)和(he)人身(shen)的(de)(de)安全防护;生产现场中往往要(yao)求电(dian)(dian)(dian)动机(ji)(ji)能(neng)及时投运(yun)并安全运(yun)行(xing)，南方(fang)环境多雨、潮湿，为保证电(dian)(dian)(dian)机(ji)(ji)不因受潮影、进水(shui)响其投运(yun)或安全运(yun)行(xing)，应(ying)(ying)制定具体的(de)(de)电(dian)(dian)(dian)机(ji)(ji)防潮措施同时应(ying)(ying)注(zhu)意潮湿环境的(de)(de)电(dian)(dian)(dian)机(ji)(ji)选(xuan)型。