Evaluate qualitatively the limitations of the ideal transformer model and the strategies used to improve transformer efficiency

Incomplete flux linkage

  • Magnetic field can always be detected near transformers, which means the magnetic field created by the primary coil doesn’t pass through the secondary coil completely.
  • strategies used to reduce flux leakage are:
    • a core of soft iron which can be easily magnetised.
    • the winding design is changed. For example the secondary coil is wound over the primary coil.

Resistive heat production and eddy currents

  • the coils heat up due to resistance. Thus energy is lost as heat.
  • the changing magnetic field passing through the iron core creates eddy currents
  • Strategies adopted to combat these problems include:
    • The iron core is constructed with multiple layers of iron which are coated with insulators.
    • use ferrites as cores.

Extract from Physics Stage 6 Syllabus © 2017 NSW Education Standards Authority (NESA)