45.負相序的三相電源 ， 若負載為平衡Δ接當A相相電流為sin(120πt)A ， 則A相線電流為何?(A)sin(120πt)A(B)1.732sin(120πt+30°)A(C)1.732sin(120πt-30° )A(D)1.732sin(120πt+120° )A