Insulation Level Temperature
Y 90 ° C
A 105 ° C
E 120 ° C
B 130 ° C
F 155 ° C
H 180 ° C
C 200 ° C

The insulation classes divide insulating materials according to temperature ranges, for which they are capable. The insulation materials will lose effect by the lasting heat loss of the electric motor, transformer, generator and electrical appliance.

This chemical aging process is getting faster with increasing Temperature. Therefore insulating and impregnating mediums have to be chosen in the corresponding class, to reach a sufficient lifetime of the insulation.