Lecture on Transformers in the National Grid

Overview

• Transformers play a crucial role in the distribution of electricity in the National Grid.
• Electricity is generated at power stations and distributed across the country.
• Transformers are used to regulate voltage levels for efficient transmission and safe usage.

Purpose of Transformers

• Step-up Transformers:
  • Increase voltage to around 400,000 volts.
  • Minimize energy losses during transmission across the country.
• Step-down Transformers:
  • Decrease voltage to around 230 volts for safe use in homes.

Components of a Transformer

• Iron Core:
  • Connects the primary coil (left) to the secondary coil (right).
  • Essential for magnetic field induction.
• Primary Coil:
  • Receives alternating potential difference, causing current flow and magnetic field generation.
• Secondary Coil:
  • Induces current flow when connected in a complete circuit due to magnetic fields.

Functionality of Transformers

• Alternating Potential Difference:
  • Applied across the primary coil, inducing a magnetic field.
  • Alternates, causing alternating magnetic fields in the iron core.
• Induction Process:
  • Alternating magnetic field in primary coil transfers to iron core.
  • Iron core's magnetic field induces potential difference in the secondary coil.
• Current Flow:
  • Current is transferred through induced magnetic fields, not direct conduction.
  • Wires are insulated with plastic, preventing direct electrical conduction.

Voltage Changes

• Step-up Transformers:
  • Increase voltage by having more turns in the secondary coil than the primary.
  • Example: 10 volts in, 20 volts out.
• Step-down Transformers:
  • Decrease voltage by having fewer turns in the secondary coil.

Final Remarks

• Transformers use magnetic fields to change voltage, allowing for efficient power distribution and usage.
• Understanding the components and functions is crucial for exams and practical applications.