Patent ID: 9541580
Date: 2017-01-10
CPC Classifications: G01R,H02H

Claim:
1. A current detecting device for detecting a measurement current flowing through a conductor, comprising: an annular magnetic core around the conductor; an exciting coil wound around the magnetic core; an oscillation means for generating a square wave voltage that causes the magnetism of an exciting current supplied to the exciting coil to invert in accordance with a set threshold value, with the magnetic core in a saturated state or a state in the vicinity thereof; a first overcurrent detection means for detecting a first overcurrent indicator of the measurement current based on a variation in the duty ratio of the square wave voltage output from the oscillation means, and for outputting a first overcurrent signal based on detecting the first overcurrent indicator; a second overcurrent detection means for detecting a second overcurrent indicator of the measurement current based on the amplitude of the square wave voltage output from the oscillation means, and for outputting a second overcurrent signal based on detecting the second overcurrent indicator; a third overcurrent detection means for detecting a third overcurrent indicator of the measurement current based on the frequency of the square wave voltage output from the oscillation means, and for outputting a third overcurrent signal based on detecting the third overcurrent indicator; and an output means for generating a first overcurrent detection signal based on the first overcurrent signal, the second overcurrent signal, and the third overcurrent signal.