LOW LOSS AND LOW NOISE LOADED IRON CORE AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To provide a loaded iron core for a transformer for improving a noise and loss characteristics more sharply than an iron core using a uni-directional silicon steel board, and a method for manufacturing the loaded iron core for a transformer. SOLUTION: This iron core 1 is formed by laminating steel boards. In this loaded iron core 1, stress members 9 compressively deformed within an elastic limit are interposed between supporting parts provided in the iron core 1 is parallel with the straight side parts. It is desired that a tension which is 0.1-2.0 Kgf/mm2 is added to the straight side parts of the iron core according to the action of the stress members 9. Also, it is desired that a bidirectional silicon steel board whose mean crystal grain diameter is 3 mm or less is used for loaded iron core members. As for the arrangement of the stress members 9, the stress members 9 having dimension longer than a distance between the supporting parts only by prescribed amounts are contracted or bent within an elastic limit, and interfit between the supporting parts so as to be interposed in parallel with the straight side parts.