Which of the following loss in a transformer is zero even at full load ?
A. Core loss
B. Friction loss
C. Eddy current loss
D. Hysteresis loss
Answer: Option B
Solution (By Examveda Team)
Transformers are static electrical devices, meaning they have no moving parts.Because of this, there are no mechanical losses such as friction or windage losses, which occur only in rotating machines like motors or generators.
Core losses (which include hysteresis and eddy current losses) occur whenever the transformer core is energized — that is, even under no-load conditions. These losses depend on the supply voltage and frequency, not on the load.
Copper losses occur only when the transformer carries load current and vary with the square of the load current.
Since a transformer has no moving parts, the friction loss is zero at all times — even at full load.
Hence, the correct answer is Friction loss.

There is no moving element, so air & friction loss is always zero.
Since no rotating is there. The transformer is a static device.
Friction loss is zero because in transformer there is no rotating parts in it