What are the Types of Losses in a Transformer

The Types of Losses in a Transformer:

There are various types of losses in the transformer such as iron losses, copper losses, hysteresis losses, eddy current losses, stray loss, and dielectric losses. The various types of losses are explained below in detail.

Losses:

Iron Losses

Hysteresis Loss

Eddy Current Loss

Copper Loss Or Ohmic Loss

Stray Loss

Dielectric Loss

Iron losses:

These losses occur in the core of the transformer and are generated due to the variations in the flux. These losses depend upon the magnetic properties of the materials which are present in the core, so they are also known as iron losses, as the core of the Transformer is made up of iron. And since they do not change like the load, so these losses are also constant.

There are two types of Iron losses in the transformer:

Eddy Current losses

Hysteresis Loss

Eddy Current Losses:

When the flux links with a closed circuit, an emf is induced in the circuit and the current flows, the value of the current depends upon the amount of emf around the circuit and the resistance of the circuit. Since the core is made of 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. As these currents are not responsible for doing any useful work, and it produces a loss (I2R loss) in the magnetic material known as an Eddy Current Loss.
The eddy current loss is minimized by making the core with thin laminations.

The equation of the eddy current loss is given as

Where,

Ke – co-efficient of eddy current. Its value depends upon the nature of magnetic material like volume and resistivity of core material, thickness of laminations
Bm – maximum value of flux density in wb/m2
T – thickness of lamination in meters
F – frequency of reversal of magnetic field in Hz
V – volume of magnetic material in m3

Hysteresis Loss:

Hysteresis loss is defined as the electrical energy which is required to realign the domains of the ferromagnetic material which is present in the core of the transformer.

These domains loose their alignment when an alternating current is supplied to the primary windings of the transformer and the emf is induced in the ferromagnetic material of the core which disturbs the alignment of the domains and afterwards they do not realign properly. For their proper realignment, some external energy supply, usually in the form of current is required. This extra energy is known as Hysteresis loss.

Mathematically, they can be defined as;

Where,

KȠ is a proportionality constant which depends upon the volume and quality of the material of the core used in the transformer.
f is the supply frequency
Bmax is the maximum or peak value of the flux density

Copper Loss Or Ohmic Loss:

These losses occur in the windings of the transformer when heat is dissipated due to the current passing through the windings and the internal resistance offered by the windings. So these are also known as ohmic losses or I2R losses, where ‘I’ is the current passing through the windings and R is the internal resistance of the windings.

These losses are present both in the primary and secondary windings of the transformer and depend upon the load attached across the secondary windings since the current varies with the variation in the load, so these are variable losses.
Mathematically, these copper losses can be defined as:

Stray Loss:

The occurrence of these stray losses is due to the presence of leakage field. The percentage of these losses are very small as compared to the iron and copper losses so they can be neglected.

Dielectric Loss:

Dielectric loss occurs in the insulating material of the transformer that is in the oil of the transformer, or in the solid insulations. When the oil gets deteriorated or the solid insulation get damaged, or its quality decreases and because of this, the efficiency of transformer is effected

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