(19)
(11) EP 0 673 044 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.10.1995 Bulletin 1995/42

(43) Date of publication A2:
20.09.1995 Bulletin 1995/38

(21) Application number: 95108611.5

(22) Date of filing: 19.08.1992
(51) International Patent Classification (IPC)6: H01F 27/32, H01B 7/02
(84) Designated Contracting States:
DE FR GB

(62) Application number of the earlier application in accordance with Art. 76 EPC:
92307575.8 / 0583521

(71) Applicant: Totoku Electric Co., Ltd.
Tokyo 169 (JP)

(72) Inventors:
  • Yamaguchi, Tadashi
    Chiisagata-gun, Nagano (JP)
  • Muramatsu, Masataka
    Chiisagata-gun, Nagano (JP)
  • Katagiri, Naoki
    Ueda-shi, Nagano (JP)

(74) Representative: Calderbank, Thomas Roger et al
MEWBURN ELLIS York House 23 Kingsway
London WC2B 6HP
London WC2B 6HP (GB)


(56) References cited: : 
   
     
    Remarks:
    This application was filed on 06 - 06 - 1995 as a divisional application to the application mentioned under INID code 60.
     


    (54) Multi-layered insulated wire for high frequency transformer winding


    (57) A bundled conductor manufactured by bundling a plurality of small diameter conductors 1, or a bundled conductor 2 manufactured by giving an extremely rough twisting pitch, which is 20 times or more larger than an outer diameter of said bundled conductor, to the bundled conductor is formed. Then, an insulating layer 3 comprising 3 layers 3a, 3b and 3c, each comprising a heat-resistant plastic film, is arranged around the bundled conductor above. A required voltage resistance characteristics is provided and maintained by any 2 of the aforesaid 3 insulating layers, and each of the 3 insulating layers described above is independent respectively and can be separated from other ones.
    The multi-layered insulated wire constructed as described above is available as an insulated electric wire for a winding to be used in a transformer which satisfies various requirements for safety such as IEC and UL, and with this multi-layered insulated wire it is possible to suppress heat emission in a high frequency switching transformer.






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