Maricopa Community Colleges  ABC223   20034-20045 
Official Course Description: MCCCD Approval: 03/25/03
ABC223 20034-20045 LEC 2 Credit(s) 2 Period(s)
Electrical Distribution Systems
Distribution systems, electrical drawings and identification of electrical symbols. National Electrical Code (NEC) regulations governing distribution systems. High and low voltage portions of distribution systems. Component connection, transformer operation and calculation of transformer sizes and maximum loads for Open-Delta systems. Practical applications for capacitors and rectifiers. Calculation of power factor of electrical circuits and trouble shooting. Prerequisites: Registered Apprentice status or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
ABC223   20034-20045 Electrical Distribution Systems
1. Describe the fundamental operating aspects of a generating station and the main aspects of an electrical power system. (I)
2. Describe the role of the transmission sub-station in power distribution including: typical power ratings for large power transformers, voltage control during transmission and how sub-station equipment is rated. (II)
3. Identify, and interpret common symbols in single-line diagrams and secondary one-line diagrams and shop drawings. (III)
4. Describe how a transformer operates and explain the principle of mutual induction and how it relates to transformers. (IV)
5. Describe types of transformer core construction, list the advantages and disadvantages of specific designs and the characteristics of a well designed transformer. (V)
6. Identify specific transformer connections and differentiate their properties and uses. (VI)
7. Describe the purpose of control transformers and determine the proper type for given applications. (VII)
8. Define "overcurrent protection" related to small power transformers according to NEC specifications. (VIII)
9. Explain the need for grounding transformers and the appropriate NEC regulations for their installation. (IX)
10. Use the "Power Factor Equation" to calculate the effects of capacitors, resistors, reactors, diodes and rectifiers on an electrical system. (X)
11. Describe the purpose of vectors, perform calculations using vector principles, interpret phaser diagrams and measure voltage drop using vector principles.(XI)
12. Demonstrate specific troubleshooting procedures for transformers using appropriate testing devices. (XII)
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MCCCD Official Course Outline:
 
ABC223   20034-20045 Electrical Distribution Systems
    I. Electrical Distribution Systems
        A. Generating station
          1. Electrical components
          2. Sub-stations
        B. Synchronization
        C. Sub-station service supply
      II. Transmission Systems
          A. Sub-station switching system
          B. Voltage regulation in sub-stations
          C. Distribution systems
            1. Rural sub-stations
            2. Industrial sub-stations
            3. High voltage lines
            4. Low voltage lines
        III. Electrical Symbols
            A. Single-line drawings
            B. One-line diagram interpretation
              1. Service order numbers
              2. Unit numbers
              3. Title block
              4. Revision notes
            C. Secondary one-line diagram interpretation
            D. Shop drawings
          IV. Transformers
              A. Mutual induction
              B. Induction in transformers
              C. Magnetic flux in transformers
                1. Leakage flux
                2. High leakage
                3. Low leakage
            V. Transformer Construction
                A. Core construction
                  1. Open
                  2. Closed
                  3. Shell
                  4. Core loss
                B. Core Types
                  1. Butt
                  2. Wound
                  3. Mitered
                C. Transformer characteristics
              VI. Transformer Connections/Properties/Uses
                  A. Single-phase light and power
                  B. Y-Y for light and power
                  C. Delta connected
                    1. Center tap
                    2. "high leg"
                  D. Open delta
                  E. Tee-connected
                  F. Dry type transformers
                  G. Zig-Zag
                    1. Size calculations
                    2. Current flow
                  H. Buck and boost transformers
                    1. "Boost" mode
                    2. "Buck" mode
                    3. Three phase
                    4. Single phase
                VII. Control Transformers
                    A. Purpose
                    B. Types
                    C. Characteristics
                    D. Applications
                  VIII. NEC Requirements
                      A. Overcurrent protection
                        1. NEC
                        2. Schematics
                        3. "E"/"X" fuses
                        4. Calculations
                      B. Overcurrent protection for small power transformers
                    IX. Transformer Grounding
                        A. Need
                        B. NEC Requirements
                        C. Installation
                      X. Power Factor
                          A. Calculation
                          B. Capacitors
                            1. NEC requirements
                            2. Calculations
                          C. Resistors and reactors
                          D. Diodes and rectifiers
                        XI. Vectors
                            A. Phaser diagrams
                              1. Typical vectors
                              2. Calculations
                            B. Practical application of phaser diagrams
                            C. Voltage drop
                              1. Measurement
                              2. Resistance
                              3. Inductance
                              4. Voltage/current relationship
                          XII. Trouble Shooting
                              A. Procedure
                                1. Pre-check
                                2. Double check
                                3. Find and correct
                              B. Troubleshooting
                                1. Warning signs
                                2. Causes
                                3. Diagnostic tools
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