Question

The loss of energy in the form of heat in the iron core of a transformer will be
(A) iron loss
(B) copper loss
(C) mechanical loss
(D) none of these.

Answer 1

We know that a transformer is a static electrical machine which transfers AC electrical power from one circuit to the other circuit at the constant frequency, but the voltage level can be altered that means voltage can be increased or decreased according to the requirement. In all types of transformer construction, the central iron core is constructed from a highly permeable material made from thin silicon steel laminations. These thin laminations are assembled together to provide the required magnetic path with the minimum of magnetic losses.

Complete step by step answer
As it is known that there are different kinds of losses that will occur in the transformer such as iron, copper, hysteresis, eddy, stray & dielectric. The copper loss mainly occurs due to the resistance in the transformer winding whereas hysteresis losses will occur due to the magnetization change within the core.
This is caused because although transformers are very efficient devices, small energy losses do occur in them due to four main causes: Resistance of windings – the low resistance copper wire used for the windings still has resistance and thereby contributes to heat loss. The eddy currents cause heat loss. Windage and friction losses occur in rotating parts of a machine generally in the rotor of the machine, thus they will never occur in the transformer, as the transformer does not contain any rotating part at its secondary unlike the induction motor.
Iron loss is the energy loss in the form of heat due to the formation of eddy currents in the iron core of the transformer.

Hence the correct answer is option A.

Note It is known that iron losses are caused by the alternating flux in the core of the transformer as this loss occurs in the core it is also known as Core loss. Iron loss is further divided into hysteresis and eddy current loss. The iron loss means the Electrical power loss due to magnetisation and eddy current of the core. Copper loss means there is power loss due to both internal & external load resistances on Load condition.
On the other hand, copper loss is the term often given to heat produced by electrical currents in the conductors of transformer windings, or other electrical devices. Copper losses are an undesirable transfer of energy, as are core losses, which result from induced currents in adjacent components.
Lasty, as their name suggests, mechanical losses are caused by movement of the motor. These include the friction in the motor bearings, friction between the brushes and the commutator, and drag on the rotor caused by turbulence of the air around it (sometimes referred to as windage loss).