Insulating materials used in machines like Transformers, Generators and Motors based on their thermal heat withstanding capacity.
As we know that with increase in load the temperature of winding also increases due to increase in current flows.So based on the temperature factor insulating materials are classified into various categories.
The classes of insulating materials given here.
Classes of Insulating Materials:
Insulating materials are classified into 7 classes.
Class Y – 90°C
Cotton, silk,paper and similar organic materials.
Class A – 105°C
Impregnated paper, silk, cotton, polymide,resins.
Class E – 120°C
Enameled wire insulations on base of molded polyvinyle epoxy resins, powder plastics.
Class B – 130°C
Inorganic material (Mica, Fibre, Glass, Asbestos) impregnated with varnish and other compounds.
Class F – 155°C
Mica, polyster epoxide varnished and other varnish and in the high heat resistance.
Class H – 180
Composite materials on mica, fibre glass and other asbestos bases, impregnated in the silicon rubber except other rubber compounds.
Class C – >180°C
Mica, Ceramics, Glass, Teflon and Quartz.