小型磁粉離合器運轉過程中，主、從部分必須存在某一轉速差才有轉矩傳遞。其轉矩的大小由磁場的強度和轉速差決定，勵磁電流保持不變，轉速隨磁粉制動器轉矩增加而劇烈下降，轉矩保持不變，勵磁電流減少，轉速減少得更加嚴重。

　　小型(xing)磁粉離合器(qi)適用于(yu)高頻動(dong)(dong)(dong)作的機械傳動(dong)(dong)(dong)系(xi)統，可(ke)在主(zhu)動(dong)(dong)(dong)部(bu)分(fen)運轉(zhuan)的情況下，使從動(dong)(dong)(dong)部(bu)分(fen)與(yu)主(zhu)動(dong)(dong)(dong)部(bu)分(fen)結合或分(fen)離。主(zhu)動(dong)(dong)(dong)件與(yu)從磁粉制(zhi)動(dong)(dong)(dong)器(qi)動(dong)(dong)(dong)件之(zhi)間處(chu)于(yu)分(fen)離狀態(tai)時，主(zhu)動(dong)(dong)(dong)件轉(zhuan)動(dong)(dong)(dong)，從動(dong)(dong)(dong)件靜止(zhi)；主(zhu)動(dong)(dong)(dong)件與(yu)從動(dong)(dong)(dong)件之(zhi)間處(chu)于(yu)接(jie)合狀態(tai)，主(zhu)動(dong)(dong)(dong)間帶去從動(dong)(dong)(dong)件轉(zhuan)動(dong)(dong)(dong)。

　　小型磁粉離合器由于主、從動部件間無任何機械連接，無磨損消耗，無磁粉泄漏，無沖擊，調整勵磁電流可以改變轉速，作無級變速器使用，這是它的優點。該磁粉離合器的主要缺點是轉子中的渦流會產生熱量，該熱量與轉速差成正比。低速運轉時的效率很低，效率值為主、從動軸的轉速比，即η=n2/n1。