Transformer Insulation Class

[GDL90958]

Does anyone know what temp is related to class H i have vendor literature that refers to 220 degrees C but when i look up insulation classes at other sites it refer to class H as 180 degree C

thanx

GDL

 

[gordonl]

Normally the rise on a class H transformer is 150C, over an average 30C ambient. This would give the 180C. But this is only the average coil temperature rise. The hottest spots in the coil can reach upto 220C, and above this you would experience shortening of life. So the insulation is rated for the hottest spot (220C) and not the average.

 

[GDL90958]

Is this the insulation class gordon or the transformer class that these temps refer to?

 

[gordonl]

220C is the insulation class where as 150C would be the transformer class, or transformer temperature rise.