A.動(dòng)靜鐵芯吸合不牢 B.線圈電壓過(guò)低 C.觸頭接觸電阻過(guò)大 D.觸頭所帶負(fù)載過(guò)重
A.±7% B.+7%-10% C.±10%
A.±5% B.+7%-10% C.±10%