| 摘要 |
<p>PROBLEM TO BE SOLVED: To perform GO/NO GO test correctly by one worker without removing the secondary wiring of an instrument voltage or current transformer. SOLUTION: A worker connects a DC current generator comprising a dry cell 14 and a switch 15 across a part K-L where a CT 13 for R phase is provided such that the K side of the main circuit on the primary of the CT 13 comes on the plus side. A secondary DC current is induced at a local part of the R phase provided with the CT 13 by turning the switch 15 on/off. A clamp type current detector 2 for R phase delivers a pulsating signal to the control circuit 17 in a body 1 only when the induced secondary DC current has positive polarity. Upon receiving the pulsating signal, the control circuit 17 delivers an indication command and an alarm command, respectively, to an indication circuit 18 and an alarm circuit 19. Consequently, an R phase indication lamp is lighted in red and an alarm delivers an alarm sound of predetermined tone thus notifying the worker that the secondary wiring of the CT 13 for R phase is correct.</p> |
