Separation of Core Losses in Transformer

Separation of Core Losses Calculation in a Transformer

The core loss of a transformer depends upon the frequency and the maximum flux density when the volume and the thickness of the core laminations are given. 

The core loss is made up of two parts

(i) Hysteresis loss 

Hysteresis loss in transformer is denoted as,

W_h = K_hƒ (B_m) ^1.6 watts

Hysteresis loss in a transformer occurs due to magnetization saturation in the core of the transformer.

Magnetic materials in the core will eventually become magnetically saturated when they are placed in a strong magnetic field, such as the magnetic field generated by an AC current.

(ii) Eddy 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 circulates currents within the body of the material. 

These circulating currents are called Eddy Currents. They will occur when the conductor experiences a changing magnetic field.

Eddy current loss in transformer is denoted as,

W_e = K_eƒ ²  K_f²ƒ B_m² watts

Where, 

K_h = Hysteresis constant.

K_e = Eddy current constant.

K_f= form constant.

Copper loss can simply be denoted as,

I_L²R₂′ + Stray loss

Where,

 I_L = I₂= load of the transformer, and R₂′ is the resistance of transformer referred to as secondary.

If we carry out two experiments using two different frequencies but the same maximum flux density, we should be able to find the constants K_h and K_e and hence calculate hysteresis and eddy current losses separately.