At a Glance of Transformer

Basic Principles

1. Electromagnetic Induction: Transformers work on the principle of electromagnetic induction, discovered by Michael Faraday. When an alternating current (AC) flows through a coil (the primary winding), it creates a varying magnetic field around the coil. This varying magnetic field induces a voltage in another coil (the secondary winding) placed within the magnetic field.
2. Mutual Induction: The process by which a coil of wire magnetically induces a voltage in another coil positioned nearby is called mutual induction. Transformers utilize this phenomenon to transfer energy from the primary to the secondary coil.

Construction

1. Core: The core of a transformer is typically made of laminated silicon steel to minimize energy losses due to eddy currents. The core provides a path for the magnetic flux.
2. Windings: There are two main windings in a transformer:
3. Insulation: Proper insulation is crucial to prevent electrical shorts and maintain safety.

Types of Transformers

1. Step-Up Transformer: Increases the voltage from the primary to the secondary winding. It has more turns in the secondary winding than in the primary.
2. Step-Down Transformer: Decreases the voltage from the primary to the secondary winding. It has fewer turns in the secondary winding than in the primary.
3. Isolation Transformer: Used to isolate two circuits. It has an equal number of turns in both windings, resulting in no change in voltage but providing isolation.
4. Autotransformer: A transformer with a single winding that acts as both the primary and secondary winding. It is more compact and efficient but lacks isolation.
5. Three-Phase Transformer: Used in three-phase power systems, typically in industrial applications. It can be constructed by connecting three single-phase transformers in a specific configuration or using a single three-phase transformer.

Key Parameters

1. Turns Ratio: The ratio of the number of turns in the primary winding to the number of turns in the secondary winding. It determines the voltage transformation ratio.
2. Voltage Regulation: The ability of a transformer to maintain constant secondary voltage despite variations in load.
3. Efficiency: Transformers are highly efficient, often above 95%. Efficiency is defined as the ratio of the output power to the input power.
4. Impedance: The opposition to the flow of alternating current, which affects the transformer's voltage regulation and short-circuit behavior.

Applications

1. Power Distribution: Transformers are used to step up the voltage for transmission over long distances and step down the voltage for distribution to consumers.
2. Electrical Isolation: Isolation transformers are used to isolate different parts of an electrical system for safety and protection.
3. Impedance Matching: Used in communication systems and audio equipment to match impedances for maximum power transfer.
4. Voltage Adaptation: Used in devices that require different voltage levels for operation.

Losses in Transformers

1. Core Losses: Also known as iron losses, these occur in the transformer's core due to hysteresis and eddy currents.
2. Copper Losses: Occur due to the resistance of the windings when current flows through them.
3. Leakage Flux: Not all the magnetic flux produced by the primary winding links with the secondary winding, leading to some energy loss.
4. Stray Losses: Caused by leakage fluxes inducing currents in other conductive parts of the transformer.