The purpose of this unit is to teach delta-wye and wye-delta transformer connections and how the angular displacement changes. Single-phase distribution transformers interconnected to provide various three-phase power in a number of different ways, providing a utility with the flexibility of meeting a variety of customer needs. This program demonstrates and explains how three-phase delta-wye, wye-delta, and open bank connections are made. This unit also allows the student to practice making three-phase connections.
- Demonstrate and explain how three-phase delta-wye and wye-delta connections producing 30 degrees of angular displacement are made.
- Demonstrate and explain how open connections are made.
- Recognize and use one-line diagrams for delta-wye, wye-delta, and open connections. Illustrate how to connect three single-phase transformers to supply a three-phase, three-wire delta secondary.
SUBJECTS AND OBJECTIVES
Basic Connection Requirements
- Describe the basic requirements for connecting units together to form a three-phase bank.
- Explain connections principles and theory using one-line diagrams.
- Demonstrate and explain that delta-wye three-phase connections have angular displacements of 30 degrees.
- Demonstrate and explain how a three-phase, delta-wye connection producing 30 degrees of angular displacement is made using subtractive-polarity transformers.
- Demonstrate and explain how a three-phase wye-delta connection producing 210 degrees of angular displacement is made.
- Demonstrate and explain an open delta-open delta connection producing 180 degrees of angular displacement.
- Demonstrate and explain an open wye-open delta, three-phase connection producing 210 degrees of angular displacement.
- Demonstrate and explain one example of a three-phase transformer.