| 摘要 |
<p>PURPOSE:To detect sensitively and accurately with a small and lightweight device by setting an exciting current based on a high frequency excitation part in the neighborhood of a residual magnetic flux density of magnetic hysteresis curve for an iron core and utilizing the change of incremental permeability caused by the magnetic field. CONSTITUTION:The high frequency excitation part 12 in which a high frequency excitation coil 7 is connected to a high frequency power supply 11 through e.g. a half-wave rectifying circuit with a rectifier 8 and a detection resistor 9 matched with a reactance of the iron core part, is provided in the iron core 1a. An output part 15 connected with a low-pass filter 13 and a DC removing device 14 in order is formed with the resistor 9. When the magnetic field generated from a current i0 to be detected which is made to flow in a conductor 2a passing through a center hole of the iron core 1a is applied, the change of reactance for the coil 7 according to the change of magnetic flux is abundantly appeared. So, with the condition that the magnetic field generating from the excitation part 12 is always being applied, the change of reactance according to the whole fluxes at the time when a minus hysteresis is moved thereto by the magnetic field generated from the current i0, is detected. Further by means of removing 13, 14 high frequency and DC parts, an output voltage having the correct current waveform to be detected can be taken out from the output part terminal.</p> |
