What Is the Working Principle of Transformer?

Transformers are a fundamental component of modern electrical systems, serving as the backbone for efficient power distribution across various industries. With their ability to transfer electrical energy between circuits through electromagnetic induction, transformers play an indispensable role in the transmission and distribution of electricity. In this blog, we will mainly explore the intricate working principles of transformers, shedding light on their importance and functioning principles.

What is Transformer?

Transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It is primarily used to change the voltage levels in alternating current (AC) systems.

Key Components of a Transformer

A typical transformer consists of the following key components:

Core: Made of ferromagnetic material (usually laminated silicon steel) to enhance magnetic coupling and reduce energy losses.

Primary Winding: The coil connected to the input voltage source. It generates a magnetic field when AC voltage is applied.

Secondary Winding: The coil connected to the load. It receives the induced voltage from the magnetic field created by the primary winding.

Working Principle of Transformer: Overview of How Transformers Work

The working principle of transformer is based on Faraday’s Law of Electromagnetic Induction, which states that a change in magnetic flux through a coil induces an electromotive force (EMF) in that coil. Here’s how it works in a transformer:

1. Electromagnetic Induction

AC Voltage Application: When an alternating current (AC) flows through the primary winding, it creates a time-varying magnetic field around it.

Magnetic Flux: This magnetic field passes through the core and links with the secondary winding. The core serves to direct the magnetic flux and improve efficiency.

Induction in Secondary Winding: As the magnetic field changes, it induces a voltage in the secondary winding due to the changing magnetic flux. The induced voltage depends on the number of turns in the secondary winding compared to the primary winding.

2. Magnetic Coupling

The induced magnetic field in the core links both the primary and secondary windings. This is critical for transferring energy from one coil to another. According to Faraday’s Law of electromagnetic induction, a changing magnetic flux through a coil induces an electromotive force (EMF).

3. Induced EMF in the Secondary Winding

The changing magnetic field in the core induces a voltage (EMF) in the secondary winding.

The magnitude of the induced voltage in the secondary winding can be determined using the formula:

where:
-V_s = voltage in the secondary winding
-V_p = voltage in the primary winding
-N_s = number of turns in the secondary winding
-N_p = number of turns in the primary winding

4. Voltage Transformation

If the number of turns in the secondary winding is greater than in the primary winding (Ns > Np), the transformer is a step-up transformer, which increases the voltage.

If the secondary winding has fewer turns than the primary winding (Ns < Np), it is a step-down transformer, which decreases voltage.

Working Principle of Transformer: Energy Conservation You Have to Know

In an ideal transformer (ignoring losses), the power input to the primary winding equals the power output from the secondary winding. This means:

P_p = P_s​

where:
– P_p = power in the primary circuit
– P_s = power in the secondary circuit

Working Principle of Transformer: Losses in Transformers

While the principle is straightforward, practical transformers experience some losses, including:

Copper Losses: Due to the resistance in the windings, leading to heat generation.

Core Losses: Caused by hysteresis and eddy currents in the core material.

Leakage Flux: Some magnetic flux does not link with both windings, leading to inefficiencies.

Conclusion

The transformer is a crucial component in electrical power systems, enabling the efficient transmission and distribution of electricity at various voltage levels. However, understanding its working principle is crucial in helping appreciate its role in modern electrical engineering and energy management.