高考问答ppt smartart编辑:翻译英语高手帮忙呀~！
来源：百度文库 编辑：高考问答 时间：2024/04/20 08:36:10
meters for each apartment and then to smaller disconnecting means and over-current protective devices.Branch-circuit panels are generally installed in each apartment.Feeder conductors connect the individual disconnecting means to the branch-circuit panels.Commercial and/or industrial buildings may have more than one kilowatt-hour meter,depending upon the number of occupancies.the service is usually a three-phase,four-wire system.The available voltages may be 120/208 V or 277/480 V.If the systemprovides 277/480 V,a transformer must be installed in order to obtain 120 V.If the building covera large area,it is recommended that the service be installed near the center of the building.This arrangement minimizes line loss on feeder and branch-circuit conductors.some utilities supply a three-phase,three-wire or three-phase,four-wire delta system.The common voltages that may be obtained form the three-wire delta system are 240 V,440 V or 550 V.With this arrangement ,a transformer must be used to obtain 120 V.the usual voltages supplied form the four-wire delta system are 240 V,three phase and 120 V,single phase.
米为每栋公寓然后到更小的分开的手段和过载电流保护装置。分支电路盘区在每栋公寓一般安装。饲养者指挥连接各自的分开的手段到分支电路盘区。商务和或工厂厂房也许有超过一千瓦小时米，取决于居住的数量。服务通常三相，四线制。可利用的电压也许是120/208 V或277/480 V。如果systemprovides 277/480 V，必须安装变压器为了获得120 V。如果大厦covera大区域，建议它服务在大厦附近的中心安装。这个安排在饲养者和分支电路指挥使线路损失减到最小。一些公共事业供应一三相，三导线或三相，四线式的三角洲系统。也许是得到的形式三导线三角洲系统的共同的电压是240 V， 440 V或者550 V。以这个安排，必须用于变压器获得120 V。通常电压由供应的形式四线式的三角洲系统是240 V，三相和120 V，单阶段。