| 摘要 |
<p>PURPOSE:To enhance workability and to conserve a measuring work time, by mounting a change-over operation part consisting of the shunt resistor inserted in each phase of a CT secondary circuit in series and a change-over switch for changing over said resistor and a measuring part. CONSTITUTION:When the change-over contact 15t of a change-over switch 15 is set at an OFF-position, an apparatus is in a state measuring no actual load. When the change-over contact 15t is connected to fixed contacts R1, R2, the measurement of an R-phase can be performed. By this procedure, the change- over contact 15t is successively changed over to fixed contacts S3, S4 T5, T6 N7, N8 to measure an S-phase, a T-phase and an N-phase. With respect to a phase angle, PT secondary voltage is set as reference and the phase with this low voltage is measured as a voltage-voltage phase due to a high sensitivity digital phase meter. In this system, since each phase change-over of a CT secondary current is not performed and output voltage is changed over, the open accident of a CT secondary circuit caused by change-over operation is eliminated.</p> |
