Maricopa Community Colleges  ABC268   19962-19966 
Official Course Description: MCCCD Approval: 11/28/95
ABC268 19962-19966 LEC 2 Credit(s) 2 Period(s)
Specialty Transformers and Standby Emergency System
Specialty transformers; including identification, connections, sizing and selection. Overcurrent protection, grounding, polarities, K-ratings and the effects of harmonics. Standby emergency systems to include operating principles, specific types and characteristics, sizing and selection. Use and operation of storage batteries. Hazards, switches, overcurrent protection, feeders and branch circuits for D.C. systems. National Electrical Code (NEC) requirements for installing, grounding and connecting transformers and emergency generators. Prerequisites: (Indentured status with the Arizona Builders Alliance) or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
ABC268   19962-19966 Specialty Transformers and Standby Emergency System
1. Identify specific power transformer connections and specific types of specialty transformers. (I, II)
2. Describe the sizing calculation and installation of control, constant current and other specialty transformers. (II,III)
3. Explain specific K-ratings of transformers. (IV)
4. Calculate the required size and select the correct buck-and- boost transformers according to established criteria. (IV)
5. Explain harmonics and their effect on transformer and neutral conductor size. (V, VI)
6. Describe the basic operating principles of engine-driven standby generators. (VII)
7. Identify specific types and characteristics of standby emergency electrical systems. (VIII, IX)
8. Calculate correct size and select proper standby emergency equipment for given applications. (VIII, IX)
9. Calculate correct sizes for disconnect switches, overcurrent protection devices and transfer switches. (IX)
10. Calculate correct sizes for feeder and branch circuits for D.C. systems. (IX)
11. Identify specific hazards associated with D.C. systems and describe abatement techniques. (X)
12. Describe the operating principles of manual and automatic transfer switches. (XI)
13. Describe the construction and operating principles of storage batteries. (XII)
14. Describe NEC requirements for emergency electrical systems. (XII)
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MCCCD Official Course Outline:
 
ABC268   19962-19966 Specialty Transformers and Standby Emergency System
    I. Specialty transformers
        A. Terms and definitions
          1. Ampere-turn
          2. Autotransformer
          3. Core loss
          4. Delta connection
          5. Eddy currents
          6. Harmonic
          7. Impedance
          8. Polarity
          9. Reactance
          10. Transformer potential
          11. Other ABC268Effective Term:
        B. Types
          1. Wound
          2. Doughnut
          3. Potential
        C. Internal connections in three-phase transformers
      II. Special transformers
          A. Multi-secondaries
          B. Three winding
          C. Autotransformers
            1. Operating principles
            2. National Electrical Code (NEC) requirements
          D. Zig-zag grounding
          E. Constant-current
          F. Control
          G. Series
          H. Rectifier
          I. Reactors
          J. Step-voltage regulators
          K. Specialty transformer
        III. Instrument transformers
            A. Current transformers
              1. Polarity
              2. Connections
              3. Cautions in use
            B. Potential transformers
          IV. Sizing buck-and-boost transformers - K-ratings
              A. Primary current
              B. Secondary current
              C. Demonstration calculations
            V. Harmonics
                A. Definition
                B. Defining the problem
                C. Voltage harmonics
                D. Office buildings and plants
                E. Neutral conductors
                F. Circuit breakers
                G. Busbars and connecting lugs
                H. Electrical panels
                I. Telecommunications
                J. Transformers
                K. Generators
                L. Troubleshooting
                  1. Load inventory
                  2. Transformer heat check
                  3. Transformer secondary circuit
                  4. Sub-panel neutral current check
                  5. Receptacle neutral to ground voltage check ABC268Effective Term:
                  6. True-RMS meters give you a headstart
                  7. Know your crest factor
                M. Solving the problem
                  1. In overloaded neutrals
                  2. Derating transformers
              VI. Case Study
                  A. Defining the problem
                  B. Current measurements
                  C. Subpanel
                  D. Recommendations
                VII. Standby emergency electrical systems
                    A. Terms
                      1. Alternator
                      2. Ampere-turn
                      3. Condenser
                      4. Line loss
                      5. Legally required standby systems
                      6. Rectifier
                      7. Rheostat
                      8. Solenoid
                      9. Two-step voltage regulator
                      10. Other
                    B. Single-loop generators
                  VIII. Principles and characteristics of AC generators
                      A. Alternating current
                      B. Operating characteristics of alternators
                      C. Voltage control
                      D. Load and power factor regulation
                    IX. Engine driven alternators
                        A. Standby system parameters
                          1. Fuel
                          2. Cooling
                          3. Load transfer switch
                        B. Basic generators
                          1. Shunt-field generator with commutator
                          2. Factors, revolving armature, revolving field
                          3. Shunt-field generator with rheostat
                          4. Compound generator - D.
                        C. only
                          5. Compound generator - non cranking
                          6. Shunt generators - series cranking
                        C.
                        D.
                        C. Generator with A.
                        C. winding
                          1. Basic components
                          2. Neutral point
                          3. Series connected loops
                          4. System calculations
                        D.
                        D.
                        C. hazards and abatement techniques ABC268Effective Term:
                      X. Generating current and voltage
                          A. Factors
                            1. Heat
                            2. Eddy currents
                            3. Armature reaction
                            4. Commutating (interpole) generators
                          B. Revolving armature generators
                            1. Producing a magnetic field
                            2. Using an A.
                          C. generator to produce D.
                          C.
                            3.
                          A.
                          C. generator excitation
                            4. Voltage regulation
                            5. Voltage regulators
                          C. Revolving field generators
                            1. Component parts
                            2. Schematic
                            3. Rectifier excited circuit
                          D. Brushless generator and regulator
                            1. Schematic
                            2. Voltage wave shapes
                            3. Magneciter excitation
                            4. Exciter field excitation
                            5. Amplifier circuit
                        XI. Generator operation
                            A. Types of fuel
                            B. Planning and selection of equipment
                            C. Automatic sequential paralleling
                              1. Manual transfer switch
                              2. Automatic transfer switch
                          XII. NEC requirements for emergency systems
                              A. Legally required standby systems
                              B. Sources of power
                                1. Storage batteries
                                2. Generator sets
                              C. Emergency system circuits for light and power
                                1. Health care facilities
                                2. Places of assembly
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