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Insulation Knowledge

How about the class defination of insulation materials?

How about the class defination of electrical insulation materials?
The use life of electrical insulation products is affected by many factors, the temperature usually is the aging of insulation materials and dominant factor. Therefore, there is a practical, by the world recognized heat-resistant classification method, which is the electrical insulation of the heat resistance was divided into a number of heat-resistant class. According to China standard of GB 11021-89 (IEC 85), and all heat levels and the corresponding temperature values are as following:

Insulatio Class Temp()
Y 90
A 105
E 120
B 130
F 155
H 180
C 200

If the temperature is above 250℃, the class defination shall set according to the corresponding interval of per 25℃.
As is customary the reason, now both insulating materials, insulation structures and electrical products are generally use “Thermal Resistance Class”. But from now on insulating materials will use “Temperature Index” and “Relative Temperature Index” to define the class while insulation structures and electrical products will keep to use “Thermal Resistance Class”.
To indicate the thermal resistance class of one electrical products does not mean each insulation material in this electrical product have the same insulating material temperature limitation.