| 摘要 |
PURPOSE:To enable the measurement of coersive force of a test piece simply and in a short time, by cancelling the residual magnetism of a test piece by a magnetic field generated with a demagnetizing coil to detect it with a Hall element as opposed to the test piece. CONSTITUTION:A test piece holder 44 is set at a desired position as opposed to a Hall element 55 for detecting the magnetic field of a test piece and DC excitation current is allowed to flow to a magnetizing coil 11 from a DC voltage varying circuit 21 to magnetically saturate the test piece 46 by magnetization. Then, the excitation current fed to a demagnetizing coil 12 from a DC voltage varying circuit 22 is increased sequentially to generate a magnetic field in the direction opposite to that of a magnetic field of the magnetizing coil 11. Then, the difference in the output between a Hall element 55 for detecting the magnetic field of a test piece and a Hall element 56 for detecting a magnetic field in a hollow is monitored with an X-Y recorder 30. In this manner, the coersive force of the test piece 46 is calculated from the excitation current when the difference in the output between Hall elements 55 and 56 becomes zero as the test piece 46 loses the holding force with an increase in the excitation current. |
