Richard W. Fruge, P.E. (Inactive)

Course Outline

Changes to power distribution system undervoltage relay settings often require the review of MCC motor starter coil pickup values on critical circuits. Facility loads that must operate should be evaluated for adequacy under all operational states. Component data must also be updated to reflect equipment changes or other facility modifications. Failure to review control circuit voltage calculations when the facility is modified can result in the failure of critical equipment to operate.

Design calculations prepared before the introduction of the personal computer often relied on the simplification of the analyzed circuits by the combination of series and parallel components into an equivalent circuit. Ohm's and/or Kirchoff's law was employed to analyze the circuit. These hand-written manipulations, although simple and straightforward, require numerous "hand" calculations that result in tedious, time-consuming verification and maintenance activities.

Section II demonstrates the analysis of a control circuit for a 480 V motor starter using the circuit reduction method used in many early (pre-PC) calculations. Section III demonstrates analysis of the same 480 V motor starter control circuit using mesh analysis techniques and Cramer's Rule. Section IV discusses calculation automation possibilities.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the conclusion of this 3-hour course, the student will:

• Have reviewed circuit reduction techniques;
• Have reviewed circuit analysis using Cramer's Rule;
• Have reviewed circuit analysis using Gauss-Seidel techniques;
• Recall basic circuit relationships used to convert product data for use in analysis;
• Recall circuit X/R effects on analysis;
• Recognize the usefulness of engineering "tools";
• Recognize the need to update existing calculations;
• Understand the complexities of each of the analysis methods and the benefits gained by automating the calculation process; and
• Understand the potential impact of facility configuration on equipment performance.
  
  

Intended Audience

The material presented in this module is intended for engineers responsible for analyzing power system equipment performance in other than optimum power system conditions. This course will also benefit engineers desiring a refresher course in basic circuit analysis.

Benefit to the Audience

Users of this course will be presented with situations that may require revision to design calculations and multiple methods for analyzing control circuits at reduced power system voltage levels. Development criteria for "automating" calculations are also provided.

Course Content

Table of Content

I. Component Circuit Parameters
II. Circuit Reduction Methodology
III. Analysis Using Cramer's Rule
IV. Automating Circuit Solutions
V. Course Summary

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.