[1] Univ Autonoma Metropolitana Azcapotzalco, Dept Energia, Mexico City 13, DF, Mexico
[2] Penn Transform Technol Inc, Dept Power Transformers, Canonsburg, PA USA
[3] Inst Tecnol Morelia, Programa Graduados & Invest Ingn Elect, Morelia, Michoacan, Mexico
[4] Univ Alberta, Dept Elect & Comp Engn, Edmonton, AB T6G 2V4, Canada