STRATIFIED EDDY CURRENT TYPE COIL FOR STRONG AC MAGNETIC FIELD

摘要

PURPOSE:To operate the title coil over a wide frequency range by constructing the coil out of a conductor plate for an eddy current having a slit and a conductive material coil for eddy current excitation around which a conductive material is wound into a flat plate annular shape. CONSTITUTION:Flat plate annular conductive material coils 4a, 4b are successively coupled at ends 5b, 6a thereof, and annular insulators are disposed between the coils 4a, 4b and circular conductor plates 1a-1c for electrical insulation between the latters. Herein, once an AC voltage is applied across the ends 5a, 6b, an AC magnetic flux is generated by an AC current 7, and hence an eddy current flowing oppositely to the current 7 is formed around edges of the conductor plates 1a-1c and allowed to flow peripherally of the conductor plates. Further, the eddy current is allowed to flow along slits 3a-3c in the conductor plates radially of the same and concentrated around the periphery of a hole 2, and an eddy current 10 is allowed to flow in the same direction as that of the current 7 to form an AC magnetic field in the hole 2. The just- mentioned magnetic flux and one due to the current 7 are in the same direction and hence superimposed and added to each other.