The eddy current loss in a transformer is caused by:

Eddy's current loss:

• When an alternating magnetic field is applied to a magnetic material, an emf is induced in the material itself according to Faraday’s law of Electromagnetic induction.
• Since the magnetic material is a conducting material, these EMFs circulate current within the body of the material. These circulating currents are called Eddy currents. They are produced when the conductor experiences a changing magnetic field.
   

It is given by: \(P_e=K_eB_m^2t^2f^2V\)

where Ke = Eddy current loss coefficient

Hysteresis loss:

• Hysteresis loss in a transformer refers to the energy loss that occurs in the transformer's core material due to the repeated magnetization and demagnetization (cycling) when alternating current (AC) flows through it.
• Hysteresis loss in a transformer can be minimized by using soft magnetic materials for the core like permalloy or silicon iron.
   

It is given by: \(P_h=K_hfB_m^{1.6}\)