Voltage Frequencies & Levels Variations and Foreign Electrical Systems
Bijan Ghayour, P.E.
Course Outline
This course discusses the sensitivity of the electrical systems to voltage levels and frequency variations. The course also provides guidance required to identify the voltage and frequency standards of various foreign countries for both medium and low voltage system. Foreign countries around the world use different electrical standards for voltage and frequency than those of the United States. Some electrical equipment will operate properly at an electrical frequency of either 50 or 60 Hz. Equipment designed for 60 Hz that will not operate properly at 50 Hz is termed “50 Hz sensitive,” and equipment designed for 50 Hz that will not operate properly at 60 Hz is termed “60 Hz sensitive.”
This course also discusses the effects of voltage and frequency variations on the performance of induction motors. Topics such as over and undervolatge, high or low frequency, unbalanced voltage, and single phase operation of the motors is discussed and illustrated
Appendix B covers identification of various low and medium voltage levels, along with the system frequencies, used by countries around the world. Derating factors are discussed and developed for the six generic types of equipment in chapter 3. Appendix C summarizes the derating factors presented in chapter 3 for different voltage and frequency environments.
Appendix A contains a list of publications referenced in this course.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of course materials.
Learning Objective
The purpose of this course is to make the student familiar with the effects of voltage level and frequency variations on the performances of electrical distribution systems and induction motors.
At the conclusion of the course the student will be familiar with the:
- Voltage and frequency standards of various foreign countries;
- Theoretical overview of transformer;
- Transformer saturation;
- Magnetic coupling;
- Effects of voltage level and frequency variation on:
- Heating, ventilation and air-conditioning (HVAC) equipment
- Electrical protection and protection system
- Medium voltage distribution equipment
- Safety and security equipment
- Communication system
- Lighting systems
- Other systems such as clocks, power supplies, and computers
- Derating factors for above equipment and systems;
- Frequency and single and three phase voltage levels by country;
- Effects of voltage and frequency variations on induction motor performance;
- Unbalanced operation of induction motors;
- Single phase operation of induction motors;
- Temperature rise in induction motors; and
- Overload protection of induction motors.
Intended Audience
This course is intended for professional electrical engineers, electrical designers, project engineers, and maintenance personnel involved in the application, specification, design, installation, and maintenance of electrical systems.
Benefit to Attendees
This course will assist individuals and organizations in the understanding of electrical system performances in real world situations and with respect to voltage levels and frequency variations present in almost all electrical distribution systems.
The course is also beneficial for engineers and designer designing electrical system for installation in various foreign countries.
Course Introduction
This course discusses the sensitivity of the electrical systems to voltage levels and frequency variations. The course also provides guidance required to identify the voltage and frequency standards of various foreign countries for both medium and low voltage system.
This course also discusses the effects of voltage and frequency variations on the performance of induction motors. Topics such as over and undervolatge, high or low frequency, unbalanced voltage, and single phase operation of the motors is discussed and illustrated
Course Content
The course content is contained in the following PDF file:
Voltage Frequencies & Levels Variations and Foreign Electrical Systems
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Course Summary
The course materials are based in large part on the Defense Department’s publication UFC-3-510-01 ANF, “Foreign Voltages and Frequencies Guide”
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
