| 摘要 |
<p>PURPOSE:To attain high speed switching of the direction of magnetization by selecting by cross sectional area and number of turns of the 1st coil to a specific value in the constitution that the magnetic field is held by energizing a 2nd coil after energizing a 1st coil. CONSTITUTION:In generating a magnetic field, a switch 2a is turned on at first to give a current to a coil 1a. Since the inductance of the coil 1a is smaller than that of the coil 1b, a current flows rapidly and the magnetic field generated in an electromagnet 1 rises rapidly. Then after the rising of the magnetic field by the coil 1a, the switch 2b is turned on and the switch 2a is turned off, then the magnetic field generated from the magnet 1 is held. Through the constitution above, number of turns N of the coil 1a is selected as 100<=N<=400, and the cross sectional area S(mm<2>) of the wire of the coil 1a is selected to be 0.04<=S. Thus, the rising speed is reduced remarkably at the production of magnetic field or at the inversion of the direction of magnetic field.</p> |
