如何檢測電機轉速？

1、首先將(jiang)電動機的(de)六個頭(tou)的(de)連(lian)接線和短(duan)接片都拆開，利用萬用表的(de)歐姆(mu)擋任意找出一組繞組。

2、再(zai)將萬(wan)用表(biao)撥到毫安擋(dang)的最小的一檔，分別接在這個繞組的兩端上。

3、然后，將電(dian)(dian)動(dong)(dong)(dong)機的(de)(de)(de)轉(zhuan)子慢(man)慢(man)地均勻轉(zhuan)動(dong)(dong)(dong)一圈，看(kan)看(kan)萬用(yong)表(biao)的(de)(de)(de)指針左右擺動(dong)(dong)(dong)幾次(ci)(ci)，如果擺動(dong)(dong)(dong)一次(ci)(ci)，就說明電(dian)(dian)流正(zheng)負變化一個周(zhou)期，就是(shi)二(er)極(ji)(ji)電(dian)(dian)動(dong)(dong)(dong)機。同樣的(de)(de)(de)理由，擺動(dong)(dong)(dong)兩次(ci)(ci)就是(shi)四極(ji)(ji)電(dian)(dian)動(dong)(dong)(dong)機，三次(ci)(ci)就是(shi)六極(ji)(ji)電(dian)(dian)動(dong)(dong)(dong)機。以(yi)此(ci)類推，就可以(yi)利(li)用(yong)萬用(yong)表(biao)的(de)(de)(de)毫(hao)安(an)擋位，將電(dian)(dian)動(dong)(dong)(dong)機轉(zhuan)動(dong)(dong)(dong)一圈，指針擺動(dong)(dong)(dong)幾次(ci)(ci)這個現象，判斷電(dian)(dian)動(dong)(dong)(dong)機是(shi)幾極(ji)(ji)電(dian)(dian)動(dong)(dong)(dong)機，從而(er)知道電(dian)(dian)動(dong)(dong)(dong)機的(de)(de)(de)大約轉(zhuan)速(su)（即略(lve)低于(yu)同步轉(zhuan)速(su)）。

我們知道電動(dong)機的(de)同步轉(zhuan)(zhuan)速與磁極(ji)數(shu)的(de)關系(xi)，電源頻率是(shi)(shi)(shi)50HZ時，二極(ji)是(shi)(shi)(shi)3000轉(zhuan)(zhuan)/分(fen)，四極(ji)是(shi)(shi)(shi)1500轉(zhuan)(zhuan)/分(fen)，六極(ji)是(shi)(shi)(shi)1000轉(zhuan)(zhuan)/分(fen)等等。公式是(shi)(shi)(shi)：N=6000/P（在工頻50HZ條(tiao)件(jian)，N是(shi)(shi)(shi)同步轉(zhuan)(zhuan)速，P是(shi)(shi)(shi)電機的(de)極(ji)數(shu)）。