短語(yǔ)詞組短語(yǔ)break changeover switch contact 先閉后斷換向開(kāi)關(guān)接點(diǎn)make -before-break changeover switch contact 先閉后斷換向開(kāi)關(guān)接點(diǎn)synchronized changeover contact 同步轉(zhuǎn)換接點(diǎn) 返回 changeover contact