A.220sin(ωt+90°) B.220sin(ωt-30°) C.220sin(ωt-150°) D.220sin(ωt+60°)
A.20 B.20/ C.0 D.20[]
對(duì)稱(chēng)星形負(fù)載接于三相四線制電源上,如圖10-50所示。若電源線電壓為380V,當(dāng)在D點(diǎn)斷開(kāi)時(shí),U1為()V。
A.220 B.380 C.190 D.237