一、功率表測量的是什么功率

功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)表測量的(de)(de)是(shi)電(dian)(dian)(dian)路中的(de)(de)有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)。有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)是(shi)指(zhi)電(dian)(dian)(dian)路中真正的(de)(de)功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)消耗，也稱為(wei)實(shi)際有(you)(you)用功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)，如電(dian)(dian)(dian)動機輸(shu)出(chu)的(de)(de)機械(xie)功(gong)(gong)(gong)(gong)(gong)，或者燈泡發(fa)出(chu)的(de)(de)光能。有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)與電(dian)(dian)(dian)壓和電(dian)(dian)(dian)流的(de)(de)相(xiang)位差有(you)(you)關。當電(dian)(dian)(dian)壓和電(dian)(dian)(dian)流波形完(wan)全相(xiang)同時，有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)最大(da)，當相(xiang)位差為(wei)90度時，有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)為(wei)0。

二、功率表的正確接線方法

在(zai)進行功率表接線時，必須遵守“發電機端”的接線規則。這一規則主要強調(diao)以下幾(ji)點：

1、電(dian)流(liu)線(xian)(xian)圈與(yu)電(dian)壓線(xian)(xian)圈的極性必須正確連接。標有(you)“*”或“±”號的電(dian)流(liu)端(duan)鈕應(ying)接至電(dian)源的一(yi)(yi)端(duan)，另一(yi)(yi)端(duan)應(ying)接至負(fu)載端(duan)。電(dian)流(liu)線(xian)(xian)圈需要串聯接入(ru)電(dian)路(lu)中。

2、電(dian)(dian)壓(ya)線圈的(de)接(jie)(jie)線也需遵循一(yi)定的(de)規則。標有“*”或“±”號(hao)的(de)電(dian)(dian)壓(ya)端(duan)鈕應接(jie)(jie)到(dao)電(dian)(dian)源同極性的(de)端(duan)子上，另一(yi)個電(dian)(dian)壓(ya)端(duan)鈕則跨接(jie)(jie)到(dao)負載(zai)的(de)另一(yi)端(duan)。電(dian)(dian)壓(ya)線圈并聯(lian)接(jie)(jie)入電(dian)(dian)路中。

3、如果品牌功率表的(de)接(jie)線正確，但發現功率表的(de)指針反轉(zhuan)，這(zhe)可能是因為電流端(duan)鈕(niu)的(de)連接(jie)錯誤。在這(zhe)種情況下，應將電流端(duan)鈕(niu)換接(jie)，而不是電壓(ya)端(duan)鈕(niu)。

4、功率(lv)表(biao)有兩(liang)種不(bu)同(tong)的接(jie)線(xian)方式，以滿足不(bu)同(tong)的測量需求。

5、電(dian)(dian)(dian)壓線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)前接方(fang)式(shi)：在這(zhe)種方(fang)式(shi)中，功(gong)率(lv)(lv)表(biao)(biao)(biao)電(dian)(dian)(dian)壓線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)兩端的(de)(de)電(dian)(dian)(dian)壓等于(yu)負(fu)載(zai)電(dian)(dian)(dian)壓加上功(gong)率(lv)(lv)表(biao)(biao)(biao)電(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)的(de)(de)電(dian)(dian)(dian)壓降(jiang)。這(zhe)意味著在功(gong)率(lv)(lv)表(biao)(biao)(biao)的(de)(de)讀數(shu)中會(hui)多出電(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)的(de)(de)功(gong)率(lv)(lv)消(xiao)耗。這(zhe)種接線(xian)(xian)(xian)(xian)方(fang)式(shi)適用(yong)于(yu)負(fu)載(zai)電(dian)(dian)(dian)阻遠比(bi)功(gong)率(lv)(lv)表(biao)(biao)(biao)電(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)電(dian)(dian)(dian)阻大(da)得(de)多的(de)(de)情況。在這(zhe)種電(dian)(dian)(dian)路中，功(gong)率(lv)(lv)表(biao)(biao)(biao)電(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)中的(de)(de)電(dian)(dian)(dian)流(liu)等于(yu)負(fu)載(zai)電(dian)(dian)(dian)流(liu)加上功(gong)率(lv)(lv)表(biao)(biao)(biao)的(de)(de)電(dian)(dian)(dian)壓線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)中的(de)(de)電(dian)(dian)(dian)流(liu)，即功(gong)率(lv)(lv)表(biao)(biao)(biao)的(de)(de)讀數(shu)中多了電(dian)(dian)(dian)壓線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)的(de)(de)功(gong)率(lv)(lv)消(xiao)耗。因此，這(zhe)種電(dian)(dian)(dian)路接法適用(yong)于(yu)負(fu)載(zai)電(dian)(dian)(dian)阻遠比(bi)功(gong)率(lv)(lv)表(biao)(biao)(biao)電(dian)(dian)(dian)壓線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)電(dian)(dian)(dian)阻小得(de)多的(de)(de)情況。

6、電壓(ya)線圈(quan)后(hou)接(jie)方(fang)(fang)式(shi)：這種方(fang)(fang)式(shi)與前接(jie)方(fang)(fang)式(shi)相反，電壓(ya)線圈(quan)的連接(jie)在電流線圈(quan)之后(hou)。這種接(jie)線方(fang)(fang)式(shi)適(shi)用于負(fu)載電阻較小的場合(he)，因(yin)為這樣(yang)可以減少(shao)電壓(ya)線圈(quan)的功率消耗(hao)對測量結果的影響。

7、在實(shi)(shi)際測(ce)(ce)量(liang)中，被測(ce)(ce)功率一般比儀表本(ben)身損(sun)耗大得(de)多，而功率表電(dian)流(liu)線(xian)圈的(de)損(sun)耗通常比電(dian)壓線(xian)圈損(sun)耗小，因此為了滿(man)足(zu)測(ce)(ce)量(liang)需求，通常會采用(yong)電(dian)壓線(xian)圈前接(jie)方(fang)式。然(ran)而，具體采用(yong)哪種接(jie)線(xian)方(fang)式應根(gen)據被測(ce)(ce)功率與儀表本(ben)身損(sun)耗的(de)比例來確定。在實(shi)(shi)際操作中，應根(gen)據實(shi)(shi)際情況選擇(ze)合適的(de)接(jie)線(xian)方(fang)式，并遵守相應的(de)規則進行(xing)正確接(jie)線(xian)。