58. 繞線式三相感應電動機起動時,若在轉部外加電阻,其目的為(A)起動電流減小,且起動轉矩亦減 小(B)起動電流與起動轉矩均增大(C)起動電流減小,但起動轉矩不變(D)起動電流減小,但起動轉 矩增大。