Temperature Rise
The temperature increase of transformer components above ambient at rated load, a key design parameter.
Temperature rise is the difference between operating temperature of components (windings, oil) and ambient at rated load. Critical for loading capability and insulation life.
IEC 60076-2 limits: oil-immersed Class A: 65K average winding, 60K top oil; dry-type depends on class (F: 100K).
Heat run test is mandatory type test. Methods: resistance (average), fiber optic (hot-spot). Max hot-spot determines life.
QDTB designs with thermal margins verified by factory testing. See derating guide for non-standard conditions.
Related Products
Related Terms
Hot-Spot Temperature
The highest temperature within transformer winding insulation, determining aging rate and loading capability.
Insulation Class (A/E/B/F/H)
Standardized temperature ratings for transformer insulation materials defining maximum operating temperatures.
Cooling Class (ONAN/ONAF/ODAF)
Standardized codes describing transformer cooling methods: O=Oil, N=Natural, A=Air, F=Forced, D=Directed flow.
Rated Capacity
The maximum continuous power output a transformer can deliver at specified conditions without exceeding temperature limits.
More Terms Starting with “T”
Transformer
A static device transferring energy between circuits through electromagnetic induction, changing voltage and current levels.
Tap Changer
A device adjusting transformer turns ratio by connecting to different tap points on a winding.
Three-Phase Transformer
A transformer for three-phase power systems with three winding sets on a common core.
Turns Ratio
The ratio of primary to secondary winding turns directly determining voltage transformation ratio.
More in “Performance Parameters”
Core Loss
Power dissipated in the transformer magnetic core due to hysteresis and eddy currents, also called iron loss or no-load loss.
Copper Loss
Power lost as heat in transformer windings due to electrical resistance, proportional to the square of load current.
Efficiency Class (IE1-IE4)
International classification for transformer energy efficiency, IE1 (standard) to IE4 (premium) with progressively lower losses.
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