Transformer Connections, Part 1

4.0 1 Review SKU: TDTCO00CENDuration: 60 Minutes

The purpose of this course is to teach the common types of overhead transformers and how they are connected. Both single-phase and three-phase connections are covered, but the emphasis is on three-phase connections. The course presents connection theory and demonstrates how connections are made. At the conclusion of this course, participants should be able to describe and demonstrate how to make single-phase transformer connections. They should be able to describe and demonstrate how to make three-phase connections in the wye-wye and delta-delta configurations. They should also be able to verify that a replacement transformer is the right one.

Course Details


Training Time: 60 minutes

Compatibility: Desktop Only

Based on: Industry Standards and Best Practices

Languages: English

Learning Objectives

  • Transformer Basics
  • Define the term “transformer,” and identify common types of overhead distribution transformers.
  • Identify the common designations used for primary and secondary bushings.
  • List and explain basic information found on a transformer nameplate.
  • Primary Systems
  • Differentiate between delta and wye primary systems.
  • Recognize and explain the phasor diagrams used to illustrate delta and wye systems.
  • List and explain basic requirements for connecting transformers to delta and wye systems.
  • Single-Phase Transformer Connections
  • Demonstrate and explain how single-phase transformers can be connected to supply single-phase service.
  • Three-Phase Primary Connections
  • Demonstrate and explain a three-phase delta primary connection using three single-phase transformers.
  • Demonstrate and explain a three-phase wye primary connecting using three single-phase transformers.
  • Delta Secondary Connections
  • Demonstrate and explain a three-phase delta secondary connection that provides zero degrees angular displacement.
  • Differentiate between delta-phasor diagrams with 0 degrees and 180 degrees of angular displacement.
  • List and explain the expected secondary voltages of a delta-delta connection.
  • Wye Secondary Connections
  • Explain how the coils that make up the secondary windings are connected in order to make wye connections.
  • Recognize and identify the phasor diagrams used to illustrate a wye-wye connection.
  • Demonstrate and explain how a wye-wye connection with 0 degrees of angular displacement is made.
  • List and explain the secondary voltages that can be supplied from a wye-wye connected three-phase bank.

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