一、功率表測量的是什么功率

功(gong)(gong)率(lv)表測量(liang)的(de)(de)是電(dian)路中(zhong)(zhong)的(de)(de)有(you)功(gong)(gong)功(gong)(gong)率(lv)。有(you)功(gong)(gong)功(gong)(gong)率(lv)是指電(dian)路中(zhong)(zhong)真(zhen)正的(de)(de)功(gong)(gong)率(lv)消耗(hao)，也稱為(wei)實(shi)際有(you)用功(gong)(gong)率(lv)，如電(dian)動機輸出的(de)(de)機械功(gong)(gong)，或者燈泡(pao)發出的(de)(de)光(guang)能。有(you)功(gong)(gong)功(gong)(gong)率(lv)與電(dian)壓和電(dian)流的(de)(de)相位(wei)差有(you)關。當(dang)電(dian)壓和電(dian)流波形完全相同時(shi)，有(you)功(gong)(gong)功(gong)(gong)率(lv)最大，當(dang)相位(wei)差為(wei)90度時(shi)，有(you)功(gong)(gong)功(gong)(gong)率(lv)為(wei)0。

二、功率表的正確接線方法

在進(jin)行功率表接線(xian)時，必須遵守“發電機端(duan)”的接線(xian)規則。這(zhe)一規則主要強調以下幾點(dian)：

1、電流線(xian)圈與電壓線(xian)圈的(de)極性(xing)必須正確(que)連接(jie)。標有“*”或“±”號的(de)電流端(duan)鈕應接(jie)至電源的(de)一端(duan)，另一端(duan)應接(jie)至負載端(duan)。電流線(xian)圈需要串聯接(jie)入電路中。

2、電(dian)(dian)壓(ya)線(xian)圈的接(jie)線(xian)也(ye)需(xu)遵(zun)循(xun)一(yi)定的規則。標有“*”或(huo)“±”號(hao)的電(dian)(dian)壓(ya)端(duan)鈕(niu)應接(jie)到電(dian)(dian)源同極性的端(duan)子上，另一(yi)個電(dian)(dian)壓(ya)端(duan)鈕(niu)則跨(kua)接(jie)到負載(zai)的另一(yi)端(duan)。電(dian)(dian)壓(ya)線(xian)圈并聯(lian)接(jie)入電(dian)(dian)路中。

3、如果品牌功率表的接線正確(que)，但發(fa)現功率表的指針反轉，這(zhe)可(ke)能(neng)是(shi)因為電流端鈕(niu)的連接錯(cuo)誤。在(zai)這(zhe)種情況下，應將電流端鈕(niu)換接，而不是(shi)電壓端鈕(niu)。

4、功率(lv)表有兩種不(bu)同的接線方式，以滿(man)足(zu)不(bu)同的測量需求。

5、電(dian)(dian)壓(ya)線(xian)(xian)圈(quan)前接(jie)方式：在(zai)這種(zhong)方式中(zhong)，功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)電(dian)(dian)壓(ya)線(xian)(xian)圈(quan)兩端的電(dian)(dian)壓(ya)等于(yu)負(fu)載(zai)電(dian)(dian)壓(ya)加上(shang)功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)電(dian)(dian)流(liu)線(xian)(xian)圈(quan)的電(dian)(dian)壓(ya)降(jiang)。這意味著在(zai)功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)的讀(du)數中(zhong)會(hui)多(duo)(duo)出(chu)電(dian)(dian)流(liu)線(xian)(xian)圈(quan)的功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)消耗(hao)。這種(zhong)接(jie)線(xian)(xian)方式適用(yong)于(yu)負(fu)載(zai)電(dian)(dian)阻(zu)遠比功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)電(dian)(dian)流(liu)線(xian)(xian)圈(quan)電(dian)(dian)阻(zu)大得多(duo)(duo)的情況(kuang)。在(zai)這種(zhong)電(dian)(dian)路中(zhong)，功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)電(dian)(dian)流(liu)線(xian)(xian)圈(quan)中(zhong)的電(dian)(dian)流(liu)等于(yu)負(fu)載(zai)電(dian)(dian)流(liu)加上(shang)功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)的電(dian)(dian)壓(ya)線(xian)(xian)圈(quan)中(zhong)的電(dian)(dian)流(liu)，即功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)的讀(du)數中(zhong)多(duo)(duo)了電(dian)(dian)壓(ya)線(xian)(xian)圈(quan)的功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)消耗(hao)。因此，這種(zhong)電(dian)(dian)路接(jie)法適用(yong)于(yu)負(fu)載(zai)電(dian)(dian)阻(zu)遠比功(gong)(gong)(gong)率(lv)(lv)(lv)(lv)(lv)表(biao)(biao)電(dian)(dian)壓(ya)線(xian)(xian)圈(quan)電(dian)(dian)阻(zu)小得多(duo)(duo)的情況(kuang)。

6、電(dian)(dian)壓(ya)線圈(quan)(quan)后接(jie)方式：這種方式與前(qian)接(jie)方式相反(fan)，電(dian)(dian)壓(ya)線圈(quan)(quan)的連(lian)接(jie)在電(dian)(dian)流線圈(quan)(quan)之后。這種接(jie)線方式適用于負(fu)載電(dian)(dian)阻較小的場合，因為這樣可以減少電(dian)(dian)壓(ya)線圈(quan)(quan)的功率消耗對測量結果的影響(xiang)。

7、在實(shi)際測量中，被(bei)測功率(lv)(lv)一般(ban)比(bi)(bi)儀表本身(shen)損耗大得多，而(er)功率(lv)(lv)表電(dian)流線(xian)圈的(de)(de)損耗通常(chang)(chang)比(bi)(bi)電(dian)壓(ya)線(xian)圈損耗小，因此為了滿(man)足測量需求，通常(chang)(chang)會采用(yong)(yong)電(dian)壓(ya)線(xian)圈前接(jie)(jie)方(fang)式(shi)。然而(er)，具體采用(yong)(yong)哪(na)種接(jie)(jie)線(xian)方(fang)式(shi)應(ying)(ying)(ying)根據被(bei)測功率(lv)(lv)與(yu)儀表本身(shen)損耗的(de)(de)比(bi)(bi)例來確定(ding)。在實(shi)際操作中，應(ying)(ying)(ying)根據實(shi)際情(qing)況選擇(ze)合適的(de)(de)接(jie)(jie)線(xian)方(fang)式(shi)，并遵(zun)守相(xiang)應(ying)(ying)(ying)的(de)(de)規(gui)則進行正(zheng)確接(jie)(jie)線(xian)。