什么是大(da)功率繞線電阻？

大功率繞線電阻的額定功率通常(chang)在1W以上，甚至高(gao)達幾百瓦，可(ke)以在較高(gao)的環境溫度(du)下(xia)使用。電阻值可(ke)以從零(ling)點幾歐姆到(dao)幾百千歐姆，一(yi)般電阻精(jing)度(du)為±5%和±10%。大功率繞(rao)線電阻的組(zu)成(cheng)部(bu)分有骨架、繞(rao)組(zu)、端子和保護層。

大功率(lv)繞(rao)線電阻的阻值是多少？

大(da)(da)功率繞(rao)線(xian)(xian)(xian)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)是由(you)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)絲繞(rao)在(zai)絕(jue)(jue)緣(yuan)框架上制(zhi)(zhi)成的(de)固定(ding)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器。電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)絲一般采(cai)用鎳鉻(ge)、錳(meng)銅等合金制(zhi)(zhi)成，絕(jue)(jue)緣(yuan)骨架通常(chang)為(wei)(wei)氧化鋁陶瓷，封裝材料有絕(jue)(jue)緣(yuan)漆(qi)、硅(gui)樹脂、油漆(qi)、陶瓷、鋁殼等。以ResistorToday的(de)大(da)(da)功率繞(rao)線(xian)(xian)(xian)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)為(wei)(wei)例。 HS系(xi)列大(da)(da)功率繞(rao)線(xian)(xian)(xian)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)阻(zu)(zu)(zu)(zu)(zu)值范(fan)圍為(wei)(wei)5mΩ-100KΩ。線(xian)(xian)(xian)繞(rao)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器是用鎳鉻(ge)線(xian)(xian)(xian)、錳(meng)銅線(xian)(xian)(xian)、康銅線(xian)(xian)(xian)繞(rao)在(zai)瓷管上制(zhi)(zhi)成的(de)。它們分為(wei)(wei)固定(ding)式(shi)(shi)和可調(diao)式(shi)(shi)。大(da)(da)功率線(xian)(xian)(xian)繞(rao)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)器的(de)優點(dian)：極高的(de)阻(zu)(zu)(zu)(zu)(zu)值精度、工作時噪音低、穩定(ding)可靠、溫度系(xi)數(shu)小、能耐(nai)高溫，在(zai)環(huan)境溫度170℃下仍(reng)能正常(chang)工作。線(xian)(xian)(xian)繞(rao)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)的(de)缺點(dian)：尺寸(cun)大(da)(da)、阻(zu)(zu)(zu)(zu)(zu)值低，大(da)(da)多在(zai)100KΩ以下。另(ling)外，由(you)于(yu)結構(gou)原因，其分布電(dian)(dian)容和電(dian)(dian)感(gan)較(jiao)大(da)(da)，不能用于(yu)高頻電(dian)(dian)路。由(you)于(yu)繞(rao)線(xian)(xian)(xian)電(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)對電(dian)(dian)流起到扼流作用，電(dian)(dian)流很(hen)難通過。

電(dian)(dian)(dian)(dian)阻(zu)器(qi)在使用過程(cheng)中不能超過電(dian)(dian)(dian)(dian)阻(zu)器(qi)的(de)[敏感(gan)詞]工(gong)作(zuo)電(dian)(dian)(dian)(dian)壓(ya)。例如1/4W 10K電(dian)(dian)(dian)(dian)阻(zu)的(de)[敏感(gan)詞]工(gong)作(zuo)電(dian)(dian)(dian)(dian)壓(ya)為V==50V，而不是(shi) 4.0 中的(de) 250V。或(huo)者1/4W 1M，計(ji)算V==500V此時的(de)[敏感(gan)詞]工(gong)作(zuo)電(dian)(dian)(dian)(dian)壓(ya)是(shi)4.0中的(de)250V，不是(shi)計(ji)算出來的(de)500V，取兩者中較小(xiao)的(de)值(zhi)(zhi)。大(da)功(gong)率(lv)電(dian)(dian)(dian)(dian)阻(zu)的(de)阻(zu)值(zhi)(zhi)與其功(gong)率(lv)沒有[敏感(gan)詞]恒定(ding)的(de)關系。當(dang)電(dian)(dian)(dian)(dian)壓(ya)一(yi)定(ding)時，電(dian)(dian)(dian)(dian)功(gong)率(lv)與電(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)成反比(bi)；當(dang)電(dian)(dian)(dian)(dian)流一(yi)定(ding)時，電(dian)(dian)(dian)(dian)功(gong)率(lv)與電(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)成正比(bi)。

控制柜為什么要用(yong)大功率(lv)繞線電阻

并不是控(kong)制(zhi)(zhi)(zhi)柜(ju)(ju)一定要(yao)(yao)用大(da)功(gong)(gong)(gong)率(lv)繞線(xian)電阻，而(er)是大(da)功(gong)(gong)(gong)率(lv)線(xian)繞電阻必須完(wan)成其(qi)控(kong)制(zhi)(zhi)(zhi)所需(xu)(xu)要(yao)(yao)的功(gong)(gong)(gong)能(neng)。如果(guo)不需(xu)(xu)要(yao)(yao)，可(ke)以(yi)完(wan)全使用。許多控(kong)制(zhi)(zhi)(zhi)柜(ju)(ju)不需(xu)(xu)要(yao)(yao)大(da)功(gong)(gong)(gong)率(lv)繞線(xian)電阻，而(er)且這(zhe)種需(xu)(xu)要(yao)(yao)也很少。例如，大(da)量普通(tong)電機(ji)啟動(dong)控(kong)制(zhi)(zhi)(zhi)柜(ju)(ju)不需(xu)(xu)要(yao)(yao)大(da)功(gong)(gong)(gong)率(lv)線(xian)繞電阻，而(er)電機(ji)變頻啟動(dong)控(kong)制(zhi)(zhi)(zhi)柜(ju)(ju)則需(xu)(xu)要(yao)(yao)大(da)功(gong)(gong)(gong)率(lv)線(xian)繞電阻作為制(zhi)(zhi)(zhi)動(dong)電阻。