| 摘要 |
PURPOSE:To make voltages at both ends of a pipeline at the same phase and to require no insulation between the pipeline and buildings by connecting one phase of a three-phase power supply to both ends of the pipeline and by connecting other two phases to the intermediate portions of the pipeline at a proper distance to flow the current. CONSTITUTION:One phase of a three-phase power supply is connected to both ends of a pipeline and other two phases are connected to the intermediate portions of the pipeline at a proper distance to flow the current. Connecting points are, for instance, those points to divide the length of the pipeline into three uniform portions, and if the power supply is assumed as 200V, the secondary voltage from a three-phase transformer can be used as one third or less as compared with that when a single-phase power supply is used. Accordingly, voltages at both ends of the pipeline can be made at the same phase, thereby no insulation is required between the pipeline and buildings and the voltage one- third of that in the past can meet the requirement, resulting in a safer operation. |
