Dnk:
Temperature rise is, as the name implies, the maximum allowable temperature above the ambient or room temperature.
Equipment life shortens considerably when the total rise exceeds the limit, or if the sum of ambient and temp. rise exceeds the insulation's safe temperature.
In your example, you're well within safe boundaries unless the room [ambient] temperature is at or near 70C!!
This applies to motors, transformers and conductors.
edit: IIRC I think most manufacturer's base allowable capacity (In kva) based on an ambient of 30C.
[This message has been edited by mxslick (edited 08-19-2005).]
