通用變頻器的選型規範
bianpinqidezhengquexuanzeduiyukongzhixitongdezhengchangyunxingshifeichangguanjiande。xuanzebianpinqishibixuyaochongfenlejiebianpinqisuoqudongdefuzaitexing。renmenzaishijianzhongchangjiangshengchanjixiefenweisanzhongleixing:恒轉矩負載、恒功率負載和風機、水泵負載。
恒轉矩負載:
負載轉矩TL與轉速n無關,任何轉速下TL總保持恒定或基本恒定。例如傳送帶、攪拌機,擠壓機等摩擦類負載以及吊車、提升機等位能負載都屬於恒轉矩負載。
bianpinqituodonghengzhuanjuxingzhidefuzaishi,disuxiadezhuanjuyaozugouda,bingqieyouzugoudeguozainengli。ruguoxuyaozaidisuxiawensuyunxing,yinggaikaolvbiaozhunyibudiandongjidesanrenengli,bimiandiandongjidewenshengguogao。
恒功率負載:
機床主軸和軋機、造紙機、塑料薄膜生產線中的卷取機、開(kai)卷(juan)機(ji)等(deng)要(yao)求(qiu)的(de)轉(zhuan)矩(ju),大(da)體(ti)與(yu)轉(zhuan)速(su)成(cheng)反(fan)比(bi),這(zhe)就(jiu)是(shi)所(suo)謂(wei)的(de)恒(heng)功(gong)率(lv)負(fu)載(zai)。負(fu)載(zai)的(de)恒(heng)功(gong)率(lv)性(xing)質(zhi)應(ying)該(gai)是(shi)就(jiu)一(yi)定(ding)的(de)速(su)度(du)變(bian)化(hua)範(fan)圍(wei)而(er)言(yan)的(de)。當(dang)速(su)度(du)很(hen)低(di)時(shi),受(shou)機(ji)械(xie)強(qiang)度(du)的(de)限(xian)製(zhi),TLbukenengwuxianzengda,zaidisuxiazhuanbianweihengzhuanjuxingzhi。fuzaidehenggonglvquhehengzhuanjuquduichuandongfangandexuanzeyouhendadeyingxiang。diandongjizaihengcitongtiaosushi,zuidarongxushuchuzhuanjububian,shuyuhengzhuanjutiaosu;erzairuocitiaosushi,zuidarongxushuchuzhuanjuyusuduchengfanbi,shuyuhenggonglvtiaosu。ruguodiandongjidehengzhuanjuhehenggonglvtiaosudefanweiyufuzaidehengzhuanjuhehenggonglvfanweixiangyizhishi,jisuowei“匹配”的情況下,電動機的容量和變頻器的容量均最小。
風機、泵類負載:
在各種風機、水泵、油泵中,隨葉輪的轉動,空氣或液體在一定的速度範圍內所產生的阻力大致與速度n的2次方成正比。隨著轉速的減小,轉速按轉速的2次方減小。這種負載所需的功率與速度的3次方成正比。當所需風量、流量減小時,利用變頻器通過調速的方式來調節風量、流量,可以大幅度地節約電能。由於高速時所需功率隨轉速增長過快,與速度的三次方成正比,所以通常不應使風機、泵類負載超工頻運行。
ximenzigongsikeyitigongbutongleixingdebianpinqi,yonghukeyigenjuzijideshijigongyiyaoqiuheyunyongchanghexuanzebutongleixingdebianpinqi。zaixuanzebianpinqishiyinzhuyiyixiajidianzhuyishixiang:
1.根據負載特性選擇變頻器,如負載為恒轉矩負載需選擇siemensMMV/MDV變頻器,如負載為風機、泵類負載應選擇siemensECO變頻器。
2.選(xuan)擇(ze)變(bian)頻(pin)器(qi)時(shi)應(ying)以(yi)實(shi)際(ji)電(dian)機(ji)電(dian)流(liu)值(zhi)作(zuo)為(wei)變(bian)頻(pin)器(qi)選(xuan)擇(ze)的(de)依(yi)據(ju),電(dian)機(ji)的(de)額(e)定(ding)功(gong)率(lv)隻(zhi)能(neng)作(zuo)為(wei)參(can)考(kao)。另(ling)外(wai)應(ying)充(chong)分(fen)考(kao)慮(lv)變(bian)頻(pin)器(qi)的(de)輸(shu)出(chu)含(han)有(you)高(gao)次(ci)諧(xie)波(bo),會(hui)造(zao)成(cheng)電(dian)動(dong)機(ji)的(de)功(gong)率(lv)因(yin)數(shu)和(he)效(xiao)率(lv)都(dou)會(hui)變(bian)壞(huai)。因(yin)此(ci),用(yong)變(bian)頻(pin)器(qi)給(gei)電(dian)動(dong)機(ji)供(gong)電(dian)與(yu)用(yong)工(gong)頻(pin)電(dian)網(wang)供(gong)電(dian)相(xiang)比(bi)較(jiao),電(dian)動(dong)機(ji)的(de)電(dian)流(liu)增(zeng)加(jia)10%而溫升增加20%左右。所以在選擇電動機和變頻器時,應考慮到這中情況,適當留有裕量,以防止溫升過高,影響電動機的使用壽命。
3.bianpinqiruoyaochangdianlanyunxingshi,cishiyinggaicaiqucuoshiyizhichangdianlanduidiouhedianrongdeyingxiang,bimianbianpinqichulibugou。suoyibianpinqiyingfangdayidangxuanzehuozaibianpinqideshuchuduananzhuangshuchudiankangqi。
4.dangbianpinqiyongyukongzhibingliandejitaidianjishi,yidingyaokaolvbianpinqidaodiandongjidedianlandechangduzonghezaibianpinqiderongxufanweinei。ruguochaoguoguidingzhi,yaofangdayidanghuoliangdanglaixuanzebianpinqi。lingwaizaicizhongqingkuangxia,bianpinqidekongzhifangshizhinengweiV/F控製方式,並且變頻器無法保護電動機的過流、過載保護,此時需在每台電動機上加熔斷器來實現保護。
5.對於一些特殊的應用場合,如高環境溫度、高開關頻率、高海拔高度等,此時會引起變頻器的降容,變頻器需放大一檔選擇。
6.shiyongbianpinqikongzhigaosudianjishi,youyugaosudiandongjidediankangxiao,gaocixieboyizengjiashuchudianliuzhi。yinci,xuanzeyongyugaosudiandongjidebianpinqishi,yingbiputongdiandongjidebianpinqishaodayixie。
7.bianpinqiyongyubianjidiandongjishi,yingchongfenzhuyixuanzebianpinqiderongliang,shiqizuidaedingdianliuzaibianpinqideedingshuchudianliuyixia。lingwai,zaiyunxingzhongjinxingjishuzhuanhuanshi,yingxiantingzhidiandongjigongzuo,fouzehuizaochengdiandongjikongzhuan,elieshihuizaochengbianpinqisunhuai。
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