| 摘要 |
PROBLEM TO BE SOLVED: To provide a polarity inspecting apparatus for quickly and reliably detecting polarity failure in a current transformer. SOLUTION: The polarity inspecting apparatus 1 allows the same primary current to flow to a conforming current transformer 2 and a current transformer 3 to be inspected having the same characteristics, converts a voltage signal by resistors 4, 5 having the same resistance being connected to the secondary output of the respective current transformers 2, 3, amplifies respective voltage signals by the amplifiers 6, 7 having the same degree of amplification, and subtracts the output voltage of the respective amplifiers 6, 7 by a subtractor 8 for outputting. When the polarity of the current transformer 3 in an article to be inspected differs from that of the conforming current transformer 2, an output voltage exceeding a fixed value is outputted from the subtractor for turning on a switching element 11. A reporting apparatus such as an LED 12 and a buzzer 13 is operated. When the polarity of the current transformer 3 in the article to be inspected is the same as that of the conforming current transformer 2, nearly no output voltage is available from the subtractor 8 for preventing the switching element 11 from being turned on. Then, the reporting apparatus such as the LED 12 and the buzzer 13 cannot be operated. COPYRIGHT: (C)2004,JPO
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