Insulation and overheating temperature

Insulation
The insulating materials are selected so as to ensure good protection against chemical agents, gases, vapours, dust, oils and moisture.
Insulating materials are in class F or H of IEC 85 and more precisely:
• Enameled copper resistant up to 200° C (class H)
• Slot bottom and phase separators in leaves polyesters (class F)
• Impregnation with phenolic resin mixed with resins
polyester (class H)

Temperature limits for insulating materials (IEC 85)

Insulation class Temperature [° C]
B
130
F
155
H
180


Overheating:
Standard single speed motors and in continuous service (S1) have the overheating temperature in class B limits.
Bigger and double speed motors normally have the overheating temperature within the limits of class F.

Limits of temperature elevation for rotating machines (IEC 34-1)

Insulation class

Maximum elevation
of temperature [K]

B
80
F
105
H
125