question about transformer

[madeza]

the next expression: transformer derating
what does it mean...? or what does it involve...?
thanks for your help

 

[keith1200rs]

'Derating' normally refers to reducing a rating due to temperature. So a transformer rated at 12VA at 50 degrees C may be derated to 9VA at 70C, for example. So, if you want to use it at high temperatures you cannot get as much power from it.

Keith

 

[umesh49]

Idealy every device is capable to handle infinte power if the device temperature is not allowed to increased beyond the defined limit. If ambient temprature is more than internal winding temperature will reach to maximum allowed temperature sooner (I mean at low power) than if ambient temperature is less. So transformer r any elec. device is defined to have differrent power capabillity at differrent ambiets. This is qualitatively described as derating factor.