一、功率表測量的是什么功率

功(gong)(gong)(gong)(gong)(gong)率(lv)表測量的(de)是電(dian)(dian)(dian)(dian)(dian)路中(zhong)的(de)有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)。有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)是指(zhi)電(dian)(dian)(dian)(dian)(dian)路中(zhong)真(zhen)正的(de)功(gong)(gong)(gong)(gong)(gong)率(lv)消耗，也稱為(wei)實際(ji)有(you)(you)用功(gong)(gong)(gong)(gong)(gong)率(lv)，如電(dian)(dian)(dian)(dian)(dian)動機輸出(chu)(chu)的(de)機械(xie)功(gong)(gong)(gong)(gong)(gong)，或者燈泡發出(chu)(chu)的(de)光能。有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)與(yu)電(dian)(dian)(dian)(dian)(dian)壓和電(dian)(dian)(dian)(dian)(dian)流的(de)相位差有(you)(you)關。當電(dian)(dian)(dian)(dian)(dian)壓和電(dian)(dian)(dian)(dian)(dian)流波形(xing)完全相同時(shi)，有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)最大，當相位差為(wei)90度(du)時(shi)，有(you)(you)功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率(lv)為(wei)0。

二、功率表的正確接線方法

在(zai)進(jin)行功率表(biao)接(jie)線時，必須遵守“發電機(ji)端(duan)”的接(jie)線規則。這一規則主要強調(diao)以下幾點：

1、電(dian)(dian)流(liu)線(xian)圈(quan)與電(dian)(dian)壓(ya)線(xian)圈(quan)的極性(xing)必須(xu)正(zheng)確連接。標(biao)有“*”或“±”號的電(dian)(dian)流(liu)端鈕應接至電(dian)(dian)源的一(yi)端，另一(yi)端應接至負載端。電(dian)(dian)流(liu)線(xian)圈(quan)需要串聯接入(ru)電(dian)(dian)路(lu)中。

2、電(dian)壓(ya)(ya)線圈的(de)接(jie)線也需遵循一(yi)定的(de)規則。標有“*”或“±”號的(de)電(dian)壓(ya)(ya)端(duan)(duan)鈕應接(jie)到電(dian)源同(tong)極(ji)性的(de)端(duan)(duan)子上(shang)，另(ling)一(yi)個電(dian)壓(ya)(ya)端(duan)(duan)鈕則跨(kua)接(jie)到負(fu)載(zai)的(de)另(ling)一(yi)端(duan)(duan)。電(dian)壓(ya)(ya)線圈并(bing)聯(lian)接(jie)入電(dian)路中。

3、如果品牌功率表的接線正確，但發現功率表(biao)的指(zhi)針反轉，這可能是(shi)因(yin)為電(dian)流端鈕的連接錯誤。在這種情況下(xia)，應將電(dian)流端鈕換接，而不是(shi)電(dian)壓端鈕。

4、功(gong)率表有兩種不(bu)同的接(jie)線方式，以(yi)滿足不(bu)同的測量需(xu)求。

5、電(dian)(dian)(dian)(dian)(dian)壓(ya)線圈(quan)(quan)(quan)前接方式(shi)：在(zai)這(zhe)種方式(shi)中(zhong)，功(gong)(gong)率(lv)表(biao)(biao)電(dian)(dian)(dian)(dian)(dian)壓(ya)線圈(quan)(quan)(quan)兩端的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)等(deng)于負載電(dian)(dian)(dian)(dian)(dian)壓(ya)加上(shang)功(gong)(gong)率(lv)表(biao)(biao)電(dian)(dian)(dian)(dian)(dian)流(liu)線圈(quan)(quan)(quan)的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)。這(zhe)意味(wei)著(zhu)在(zai)功(gong)(gong)率(lv)表(biao)(biao)的(de)(de)讀數(shu)中(zhong)會多(duo)出(chu)電(dian)(dian)(dian)(dian)(dian)流(liu)線圈(quan)(quan)(quan)的(de)(de)功(gong)(gong)率(lv)消(xiao)耗。這(zhe)種接線方式(shi)適用(yong)于負載電(dian)(dian)(dian)(dian)(dian)阻遠(yuan)(yuan)比功(gong)(gong)率(lv)表(biao)(biao)電(dian)(dian)(dian)(dian)(dian)流(liu)線圈(quan)(quan)(quan)電(dian)(dian)(dian)(dian)(dian)阻大得多(duo)的(de)(de)情況。在(zai)這(zhe)種電(dian)(dian)(dian)(dian)(dian)路中(zhong)，功(gong)(gong)率(lv)表(biao)(biao)電(dian)(dian)(dian)(dian)(dian)流(liu)線圈(quan)(quan)(quan)中(zhong)的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)等(deng)于負載電(dian)(dian)(dian)(dian)(dian)流(liu)加上(shang)功(gong)(gong)率(lv)表(biao)(biao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)線圈(quan)(quan)(quan)中(zhong)的(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)，即功(gong)(gong)率(lv)表(biao)(biao)的(de)(de)讀數(shu)中(zhong)多(duo)了(le)電(dian)(dian)(dian)(dian)(dian)壓(ya)線圈(quan)(quan)(quan)的(de)(de)功(gong)(gong)率(lv)消(xiao)耗。因此(ci)，這(zhe)種電(dian)(dian)(dian)(dian)(dian)路接法適用(yong)于負載電(dian)(dian)(dian)(dian)(dian)阻遠(yuan)(yuan)比功(gong)(gong)率(lv)表(biao)(biao)電(dian)(dian)(dian)(dian)(dian)壓(ya)線圈(quan)(quan)(quan)電(dian)(dian)(dian)(dian)(dian)阻小得多(duo)的(de)(de)情況。

6、電(dian)壓(ya)線(xian)圈后接(jie)方(fang)式：這種方(fang)式與前接(jie)方(fang)式相反，電(dian)壓(ya)線(xian)圈的(de)連接(jie)在電(dian)流線(xian)圈之后。這種接(jie)線(xian)方(fang)式適用于負(fu)載電(dian)阻較(jiao)小的(de)場合，因(yin)為(wei)這樣可(ke)以減少電(dian)壓(ya)線(xian)圈的(de)功率消耗對測量結果的(de)影響。

7、在實(shi)(shi)際(ji)測量中，被測功率一般比儀表(biao)本(ben)身損(sun)耗(hao)大得多，而功率表(biao)電(dian)流線(xian)圈的(de)損(sun)耗(hao)通(tong)常比電(dian)壓線(xian)圈損(sun)耗(hao)小，因此為了滿足測量需(xu)求，通(tong)常會采用電(dian)壓線(xian)圈前接(jie)(jie)方(fang)(fang)式。然而，具體(ti)采用哪(na)種接(jie)(jie)線(xian)方(fang)(fang)式應根據(ju)被測功率與儀表(biao)本(ben)身損(sun)耗(hao)的(de)比例來(lai)確(que)定(ding)。在實(shi)(shi)際(ji)操作中，應根據(ju)實(shi)(shi)際(ji)情況選(xuan)擇合適的(de)接(jie)(jie)線(xian)方(fang)(fang)式，并遵(zun)守相(xiang)應的(de)規(gui)則進(jin)行正(zheng)確(que)接(jie)(jie)線(xian)。