| 摘要 |
PURPOSE:To measure a direct current with high accuracy and high stability without being influenced by an interphase reactor of the secondary winding side by forming the other by a delta connection in case other one of the primary winding of a stepdown transformer 1, or the secondary winding of a current transformer for detecting a current of each phase is a star shape. CONSTITUTION:A current in each phase of a primary side winding 11a of a star connection of stepdown transformer 11 whose secondary side is connected to a DC converting device with a reactor 2 is detected by current transformers 5-7. The secondary winding of the current transformers 5-7 forms a three phase bridge circuit of a delta connection through rectifiers 8a-8f, and an ammeter 9 is connected to its output side. In case of currents KIx, KIw, etc. being proportional to a DC current of this DC converting device flow to the ammeter 9, a current (kit), etc. being proportional to an energizing current by the reactor 2 different by 180 degrees in phase flow in the forward and reverse directions through the rectifiers 8a, 8c, etc., and do not flow to the ammeter 9. Accordingly, a direct current of the DC converting device is measured with high accuracy and high stability without being influenced by the interphase reactor. In this regard, even when the primary winding and the secondary winding bridge are formed by delta and star connections, respectively, the same result is obtained.
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