Copper loss is present in the winding of an autotransformer, just as it is in other types of transformers. Copper loss, also known as I²R loss, occurs due to the resistance of the copper conductors in the transformer windings. When current flows through the winding, it encounters resistance, leading to the generation of heat.
In an autotransformer, which has a single winding that serves both as the primary and secondary winding, the copper loss is still present. The formula for copper loss (I²R loss) is given by: P=I²R, Where:
P is the copper loss (W),
I is the current flowing through the winding (A),
R is the resistance of the winding (Ω).
Since the same winding carries both the primary and secondary currents in an autotransformer, the total current flowing through the winding is the sum of the primary and secondary currents. Consequently, the copper loss is higher in an autotransformer compared to a traditional transformer with separate windings for primary and secondary.
Efforts are made to minimize copper loss in transformers by using conductors with low resistance and optimizing the design. The heat generated due to copper loss must be dissipated to ensure the transformer operates within acceptable temperature limits.