一、功率表測量的是什么功率

功(gong)(gong)率(lv)(lv)(lv)(lv)表測(ce)量的(de)是電(dian)路中的(de)有(you)功(gong)(gong)功(gong)(gong)率(lv)(lv)(lv)(lv)。有(you)功(gong)(gong)功(gong)(gong)率(lv)(lv)(lv)(lv)是指電(dian)路中真(zhen)正(zheng)的(de)功(gong)(gong)率(lv)(lv)(lv)(lv)消耗，也稱為實際有(you)用(yong)功(gong)(gong)率(lv)(lv)(lv)(lv)，如電(dian)動機輸出的(de)機械功(gong)(gong)，或者燈泡(pao)發(fa)出的(de)光能。有(you)功(gong)(gong)功(gong)(gong)率(lv)(lv)(lv)(lv)與電(dian)壓和電(dian)流的(de)相位差有(you)關。當電(dian)壓和電(dian)流波形完全相同時，有(you)功(gong)(gong)功(gong)(gong)率(lv)(lv)(lv)(lv)最(zui)大，當相位差為90度(du)時，有(you)功(gong)(gong)功(gong)(gong)率(lv)(lv)(lv)(lv)為0。

二、功率表的正確接線方法

在進行功率表接線(xian)時(shi)，必(bi)須(xu)遵守(shou)“發電(dian)機端”的接線(xian)規則。這一規則主(zhu)要強調以下幾點：

1、電流(liu)線(xian)圈與(yu)電壓線(xian)圈的(de)極性必須正確連接。標有(you)“*”或“±”號的(de)電流(liu)端鈕應接至(zhi)(zhi)電源(yuan)的(de)一(yi)端，另一(yi)端應接至(zhi)(zhi)負載端。電流(liu)線(xian)圈需要串聯接入電路中(zhong)。

2、電(dian)(dian)(dian)(dian)壓(ya)線圈的(de)接線也需遵循一(yi)定的(de)規則。標有“*”或“±”號的(de)電(dian)(dian)(dian)(dian)壓(ya)端(duan)鈕應接到電(dian)(dian)(dian)(dian)源同極性的(de)端(duan)子上，另一(yi)個電(dian)(dian)(dian)(dian)壓(ya)端(duan)鈕則跨接到負載的(de)另一(yi)端(duan)。電(dian)(dian)(dian)(dian)壓(ya)線圈并聯接入電(dian)(dian)(dian)(dian)路(lu)中。

3、如果品牌功率表的接(jie)線正確(que)，但發現功率表的指針(zhen)反轉(zhuan)，這可能是因(yin)為電(dian)流(liu)端(duan)鈕(niu)的連接(jie)錯誤。在這種情況(kuang)下(xia)，應(ying)將電(dian)流(liu)端(duan)鈕(niu)換(huan)接(jie)，而(er)不是電(dian)壓端(duan)鈕(niu)。

4、功率表有兩種不同(tong)的接(jie)線方式，以滿足不同(tong)的測量(liang)需求(qiu)。

5、電(dian)(dian)(dian)(dian)(dian)壓(ya)線(xian)(xian)(xian)圈(quan)(quan)前(qian)接方(fang)式(shi)：在這(zhe)種(zhong)(zhong)(zhong)方(fang)式(shi)中(zhong)，功(gong)(gong)(gong)率(lv)表電(dian)(dian)(dian)(dian)(dian)壓(ya)線(xian)(xian)(xian)圈(quan)(quan)兩端的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)等于(yu)負載(zai)電(dian)(dian)(dian)(dian)(dian)壓(ya)加上功(gong)(gong)(gong)率(lv)表電(dian)(dian)(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)圈(quan)(quan)的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)降。這(zhe)意(yi)味著在功(gong)(gong)(gong)率(lv)表的(de)(de)讀數(shu)中(zhong)會多(duo)出電(dian)(dian)(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)圈(quan)(quan)的(de)(de)功(gong)(gong)(gong)率(lv)消(xiao)(xiao)耗(hao)。這(zhe)種(zhong)(zhong)(zhong)接線(xian)(xian)(xian)方(fang)式(shi)適用于(yu)負載(zai)電(dian)(dian)(dian)(dian)(dian)阻遠比(bi)功(gong)(gong)(gong)率(lv)表電(dian)(dian)(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)圈(quan)(quan)電(dian)(dian)(dian)(dian)(dian)阻大得(de)多(duo)的(de)(de)情況。在這(zhe)種(zhong)(zhong)(zhong)電(dian)(dian)(dian)(dian)(dian)路(lu)中(zhong)，功(gong)(gong)(gong)率(lv)表電(dian)(dian)(dian)(dian)(dian)流(liu)線(xian)(xian)(xian)圈(quan)(quan)中(zhong)的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)等于(yu)負載(zai)電(dian)(dian)(dian)(dian)(dian)流(liu)加上功(gong)(gong)(gong)率(lv)表的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)線(xian)(xian)(xian)圈(quan)(quan)中(zhong)的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)，即功(gong)(gong)(gong)率(lv)表的(de)(de)讀數(shu)中(zhong)多(duo)了電(dian)(dian)(dian)(dian)(dian)壓(ya)線(xian)(xian)(xian)圈(quan)(quan)的(de)(de)功(gong)(gong)(gong)率(lv)消(xiao)(xiao)耗(hao)。因此，這(zhe)種(zhong)(zhong)(zhong)電(dian)(dian)(dian)(dian)(dian)路(lu)接法適用于(yu)負載(zai)電(dian)(dian)(dian)(dian)(dian)阻遠比(bi)功(gong)(gong)(gong)率(lv)表電(dian)(dian)(dian)(dian)(dian)壓(ya)線(xian)(xian)(xian)圈(quan)(quan)電(dian)(dian)(dian)(dian)(dian)阻小(xiao)得(de)多(duo)的(de)(de)情況。

6、電壓(ya)線圈(quan)后(hou)接(jie)(jie)(jie)方式(shi)：這種方式(shi)與(yu)前接(jie)(jie)(jie)方式(shi)相反(fan)，電壓(ya)線圈(quan)的連(lian)接(jie)(jie)(jie)在電流線圈(quan)之后(hou)。這種接(jie)(jie)(jie)線方式(shi)適(shi)用于負載電阻較小(xiao)的場合，因為這樣可以(yi)減少電壓(ya)線圈(quan)的功率消(xiao)耗(hao)對測(ce)量結果(guo)的影響。

7、在實際(ji)(ji)測量中，被測功率一般比儀表(biao)本(ben)身損(sun)耗(hao)大得多(duo)，而(er)功率表(biao)電流線圈的損(sun)耗(hao)通(tong)常比電壓(ya)線圈損(sun)耗(hao)小，因此為了滿足(zu)測量需(xu)求，通(tong)常會采用(yong)電壓(ya)線圈前(qian)接(jie)(jie)(jie)方(fang)式(shi)。然而(er)，具體采用(yong)哪種接(jie)(jie)(jie)線方(fang)式(shi)應(ying)根據被測功率與儀表(biao)本(ben)身損(sun)耗(hao)的比例來確定(ding)。在實際(ji)(ji)操作中，應(ying)根據實際(ji)(ji)情況(kuang)選擇合適的接(jie)(jie)(jie)線方(fang)式(shi)，并(bing)遵守相應(ying)的規則(ze)進(jin)行正(zheng)確接(jie)(jie)(jie)線。