Class of Insulating Matrials

 

• The temperature rise of the electric machine depends upon temperature rise of the insulating materials. 
• The different types of insulating material are classified according to maximum temperature limits.

 

Class of Insulation	Insulation	Maximum temperature limits
Y	Cotton yarns and Fabrics, paper and fibrous material of cellulose, silk neither impregnated nor immersed in liquid dielectric	90 0C
A	Cotton yarns and Fabrics, paper and fibrous material of cellulose, silk impregnated or immersed in liquid dielectric	105 0C
E	Synthetic organic films and material having same thermal stability	120 0C
B	Mica, asbestos or glass fibre base material combined with an organic binding agent	130 0C
F	Mica, asbestos or glass fibre base material combined with suitable synthetic binding  and impregnated agent	155 0C
H	Mica, asbestos or glass fibre base material combined with suitable silicon binding  and impregnated agent	180 0C
C	Mica, ceramic, glass, quartz used with or without inorganic binding agents	Above  180 0C

 

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