Title :
Thermal aging properties of mica/epoxy stator winding insulations
Author :
Kim, Hee Dong ; Kim, Tae Wan ; Kim, Jung Hoon ; Kang, Dou Yol
Author_Institution :
Korea Electr. Power Res. Inst., Taejon, South Korea
Abstract :
Electrical properties such as ac current and tan δ of mica/epoxy composite materials (130 μm) were measured using a Schering bridge. Surface conditions were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) in sound and aged specimens. Both ac current and tan δ of sound specimens were higher than those of aged specimens. FTIR results show a new peak at 1710 cm-1 for aged specimens, originating from the carbonyl group formed by oxidation during the aging process. Glass transition temperatures of sound and aged specimens are observed to be 95.43°C and 113.43°C, and increase with increase of aging time. TGA results indicate that the sound specimens contain a smaller amount of volatile components than the aged specimens
Keywords :
Fourier transform spectra; ageing; composite insulating materials; dielectric losses; epoxy insulation; filled polymers; glass transition; insulation testing; machine insulation; machine testing; mica; scanning electron microscopy; spectrochemical analysis; stators; thermal analysis; 113.43 C; 130 mum; 95.43 C; DSC; FTIR spectra; SEM; Schering bridge; TGA; ac current; aged specimens; carbonyl group; differential scanning calorimetry; electrical properties; generator stator windings; glass transition temperature; mica/epoxy stator winding insulation; oxidation; sound specimens; surface conditions; tan δ; thermal aging properties; thermogravimetric analysis; volatile components; Aging; Bridges; Composite materials; Current measurement; Electric variables measurement; Fourier transforms; Infrared spectra; Insulation; Scanning electron microscopy; Stator windings;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 1997. IEEE 1997 Annual Report., Conference on
Conference_Location :
Minneapolis, MN
Print_ISBN :
0-7803-3851-0
DOI :
10.1109/CEIDP.1997.641101
