Explain transformer construction with suitable diagram. What are important reasons for transformer failure, explain?

Transformer Construction:

Transformers are essential electrical devices used to transfer electrical energy between circuits through electromagnetic induction. They consist of two or more coils of wire known as windings, which are wound around a common magnetic core made of high-permeability material such as iron or silicon steel.

Diagram of Transformer Construction:

[Diagram of Transformer Construction]

The primary winding, connected to the input voltage source, induces a magnetic flux in the core when an alternating current (AC) flows through it. This magnetic flux passes through the secondary winding, inducing a voltage in the secondary circuit.

Important Reasons for Transformer Failure:

1. Overheating: Overheating is one of the most common reasons for transformer failure. It can be caused by excessive load currents, poor ventilation, or high ambient temperatures. Overheating leads to insulation degradation, winding deformation, and ultimately, insulation breakdown.

2. Insulation Failure: Insulation breakdown can occur due to aging, moisture ingress, or mechanical damage. Insulation failure can lead to short circuits between windings or between windings and the transformer core, resulting in catastrophic failures.

3. Short Circuits: Short circuits in the transformer windings or between windings and the core can occur due to insulation breakdown, loose connections, or manufacturing defects. Short circuits cause excessive currents to flow, leading to overheating, insulation degradation, and mechanical stresses on the windings.

4. Oil Contamination: Transformers are often filled with insulating oil for cooling and insulation purposes. Contamination of the oil by moisture, dirt, or other contaminants can degrade its insulating properties, leading to insulation breakdown and transformer failure.

5. Mechanical Stress: Mechanical stresses such as vibration, shock, and improper transportation or installation can damage transformer components, including windings, core, and insulation. Mechanical stress can weaken the structural integrity of the transformer and lead to failure over time.

6. Lightning Strikes: Lightning strikes can induce high voltages and currents in transformers, causing insulation breakdown, winding damage, and core saturation. Surge protection devices and proper grounding can help mitigate the risk of damage from lightning strikes.

Addressing these factors through regular maintenance, monitoring, and preventive measures such as oil testing, insulation resistance testing, and thermographic inspections can help mitigate the risk of transformer failure and ensure reliable operation.