JPS6486070A - Current measuring apparatus - Google Patents

Abstract

PURPOSE:To miniaturize a current measuring apparatus and to enhance the reliability thereof, by arranging a plurality of magnetic field sensors substantially equal in sensitivity to the same iron core having a gap. CONSTITUTION:A magnetic field formed by the current flowing to a conductor 1 is closed by an iron core 2 having a gap and applied to magnetic field sensors 4a, 4b in a gap part 30. The beans sent to the magnetic field sensors 4a, 4b from a measuring part 60 by optical fibers 5a, 5b are modulated in light intensity corresponding to the magnetic fields applied to the magnetic field sensors 4a, 4b to be sent to the measuring part 60 by the optical fibers 5a, 5b. Since the magnetic fields applied to the magnetic field sensors 4a, 4b are equal in magnitude and the sensitivities of the magnetic field sensors 4a, 4b are also equal, the intensity modulation ratios of two beans sent to the measuring part 60 are equal. After the beans sent from two magnetic field sensors 4a, 4b are converted to electric signals by the measuring part 60, said measuring part generates the output proportional to the current flowing to the conductor 1 or performs display.