BWE Lecture Notes: Single Phase Transformer

Introduction

• Welcome to the final chapter of BWE.
• Covered: DC, AC, 3-phase in detail. Starting with single phase transformer.
• Focus on numerical parts; theoretical parts can be read from textbooks.
• Textbook PDF will be provided if needed.

Why is a Transformer Used?

• To convert one value of AC to another value.
• Key electrical equipment, consisting of two important coils:
  • Primary Coil
  • Secondary Coil

Transformer Diagram

• Primary coil receives input.
• Secondary coil provides output.
• Core connects primary and secondary coils.

Types of Transformers

Step Up Transformer

• Increases voltage.
• More coils in secondary than in primary.

Step Down Transformer

• Decreases voltage.
• More coils in primary than in secondary.

Faraday's Law

EMF Equations

• For primary coil: E1 = -N1 (dΦ/dt)
• For secondary coil: E2 = -N2 (dΦ/dt)
• Theoretical Questions:
  • Principle of Single Phase Transformer
  • EMF Equation of Transformer
  • Transformation Ratio
  • Losses in Transformer (iron loss, core loss)

Transformation Ratio

• E2/E1 = N2/N1 = V2/V1 = I1/I2 = k
• Step Up Transformer: K > 1 (N2 > N1)

Transformer Losses

Primary Copper Loss

• I1^2 R1 * W

Secondary Copper Loss

• I2^2 R2 * W

Total Copper Loss

• WC = I1^2 R1 + I2^2 R2 W

Impedance in Transformers

• For primary coil: Z1 = √(R1^2 + X1^2)
• For secondary coil: Z2 = √(R2^2 + X2^2)

Exam Preparation

• Discussion on how to prepare for the university exam.
• Specific sessions to focus on different chapters and strategies.

Schedule Overview

• 10 AM: Successive differentiation one-shot revision.
• 1 PM: Transformer numericals, session 2.
• 4 PM: Exam preparation strategies.
• 7 PM: DC Circuit one-shot revision.

Be sure to attend all sessions and check out textbook PDFs for theoretical study.