Transformers Training

415-01 Transformer Basics

When you complete this lesson, you will be able to explain magnetism and electromagnetism and to explain the basic principles of electrical voltage transformation.

  • Explain the force of magnetism
  • Describe the molecular domains of ferromagnetic metals
  • Describe the reaction between like and unlike magnetic fields
  • Describe magnetic flux
  • Define electromagnetism
  • Explain the changes of field strength in an electromagnetic coil
  • Define permeability
  • Explain the left hand rule for coils
  • Describe the magnetic measurements of Weber, magnetic flux density, Tesla, magnetomotive force, field intensity, and reluctance
  • Describe the line voltage and the load connections to the transformer
  • Describe the property of inductance
  • Describe electromagnetic induction
  • Describe mutual induction
  • Describe Lenz’s law and self-induction
  • Describe the turns ratio between the primary and secondary windings
  • Define volts per turn
  • Explain the use of coil taps in a transformer
  • Explain transformer losses from copper loss
  • Describe transformer losses from eddy currents
  • Describe hysteresis losses
  • Define flux loss
  • Describe mutual inductance or the coefficient of coupling

415-02 Transformer Design and Components

When you complete this lesson, you will be able to visually identify the type of core construction in a transformer, describe types of transformer cooling, temperature limits, and external devices of the transformer.

  • Describe the basics of core construction
  • Describe the design of a core-type transformer
  • Describe the design of a shell-type transformer
  • Describe a toroidal core transformer
  • Describe the cause of coil movement
  • Describe types of transformer cooling
  • Describe the type of coolant used to cool transformers
  • Identify the temperature limits of a transformer
  • Explain the need for an explosion vent
  • Describe the purpose of a gas relay
  • Explain the purpose of the bushings
  • Describe the purpose of a level gauge
  • Explain the necessity of a thermometer
  • Explain the purpose of the transformer nameplate
  • Explain transformer power ratings
  • Explain the effect of sound levels of a transformer and their role in selecting a transformer

415-03 Transformer Connections

When you complete this lesson, you will be able to identify and explain how to make the most common types of connections for single-phase and three-phase transformers. You will be able to calculate the value of phase voltage and current, as well as line voltage and current.

  • Explain how a dual-voltage, single-phase transformer is wound and connected
  • Identify the primary and secondary transformer lead marking
  • Describe the relationship between each phase of three-phase voltage
  • Discuss three-phase, delta-connected line and:
    • Phase voltage
    • Phase current
  • Discuss three-phase, wye-connected line and:
    • Phase voltage
    • Phase current
  • Explain the function of the Y-point in a wye-connected transformer
  • Describe an open-delta connection and discuss the amount of current it can provide
  • Identify a scenario where a delta-wye connection may be used

415-04 Special Transformers

When you complete this lesson, you will be able to identify the various types of special transformers and describe how they are used.

  • Describe the use of a reactor in a circuit
  • Identify the circumstances when you would use a choke in a circuit
  • Explain why an isolation transformer is used to supply power to a variable speed drive
  • Describe the windings in an auto-transformer
  • Compare the purposes of buck-boost transformers, potential transformers, and current transformers
  • Identify a scenario where a control transformer is needed
  • Identify an application that requires a K-Factor transformer