Standard

 

ELT 116 – Transformers

Course Description:

Provides instruction in the theory and operation of specific types of transformers. Emphasis will be placed on National Electrical Code requirements related to the use of transformers. Topics include: transformer theory, types of transformers, National Electrical Code requirements, and safety precautions.

 

Competency Areas:

Hours:

 

 

 

Transformer Theory

Class

3

Types of Transformers

D. Lab

0

National Electrical Code Requirements 

P. Lab/O.B.I.

3

Safety Precautions

Credit

4

 

 

 

Prerequisite:

ELT 119, IFC 101

Corequisite:

 

 

Course Guide

 

Competency

After completing this section, the student will:

Hours

Class

D. Lab

P. Lab/

O.B.I.

TRANSFORMER THEORY

9

0

8

Components

Identify basic transformer components.

 

 

 

Single-phase

Calculate primary and secondary voltages.

 

 

 

 

Calculate primary and secondary currents.

 

 

 

 

Recognize a single-phase three-wire system.

 

 

 

Three-phase

Connect Wye or Delta connections on primary or secondary currents.

 

 

 

Impedance

Calculate impedance in transformers.

Calculate transformer efficiency.

 

 

 

TYPES OF TRANSFORMERS

7

0

8

Identification

Identify three-phase transformer connects.

 

 

 

 

Recognize specialty transformers.

 

 

 

 

Identify application for auto-transformers, dual-voltage transformers, and buck-boost transformers.

 

 

 

NATIONAL ELECTRICAL CODE REQUIREMENTS

7

0

8

NEC requirements

Interpret grounding requirements for transformers.

 

 

 

 

Calculate interrupting ratings for overcurrent devices on primaries and secondaries.

 

 

 

 

Guard transformers according to the provisions of the NEC.

 

 

 

SAFETY PRECAUTIONS

7

0

6

Hazards

Identify hazards that the guarding procedures of the NEC require.

 

 

 

Procedures

Develop safe installation and replacement procedures.

 

 

 

 

Suggested Resources

 

Books:

 

Herman, Stephen; Delmar’s Standard Textbook of Electricity (2nd ed.), Delmar Publishers ISBN 0-8273-8550-1

Herman, Stephen; Experiments in Electricity for use with Lab-Volt EMS Equipment, Delmar Publishers ISBN 0-8273-8552-8

Herman, Stephen and Singleton, Donald; Delmar’s Standard Guide – Transformers, Published by Delmar Publishers, ISBN 0-8273-7209-4

Rockis/Mazur; Electric Motor Controls (2nd ed.), American Technical Publishers ISBN 0-8269-1675-9

Rockis/Mazur; Electric Motor Controls Workbook (2nd ed.), American Technical Publishers ISBN 0-8269-1676-7

Stallcup; Stallcups Electrical Design Book for 2002, Publisher NFPA, ISBN G4-SED-02

NEC 2002 Code, NFPA, Delmar Publishers ISBN 0-8776-5460-3