三线白底平开关three-wire white base flat switch
三相三线有功电度表three-phase three-wire watt-hour meter
【运输】三线制three-wire system
三线发电机three-wire generator
三线胶底平开关three-wire rubber base flat switch
三线式发电机three-wire system generator
【电】 二相三线系统tow-phase three-wire system
两相三线制two-phase three-wire system【电】