Maricopa Community Colleges  ABC262   19952-19956 
Official Course Description: MCCCD Approval: 11/28/95
ABC262 19952-19956 L+L 2 Credit(s) 2 Period(s)
Transformers and Welding Machines
Specialty transformers; types, size calculations and installation methods. Standby emergency electrical systems including various types of generators. Electrical welders, setup and welding cables. Includes National Electrical Code (NEC) requirements. Prerequisites: (Indentured status with Associated Builders and Contractors, Inc., and ABC125) or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
ABC262   19952-19956 Transformers and Welding Machines
1. Identify and describe power transformer connections and special transformers. (I, II)
2. Describe how to size, install and connect controls for shielded, constant-current and other specific specialty transformers. (II, III)
3. Explain the purpose of instrument transformers and describe specific types including buck-and-boost transformers. (III, IV)
4. Describe specific operating principles of engine driven standby generators and describe specific types and characteristics of standby emergency electrical systems. (IV, V)
5. Explain the applications of a revolving armature generator and a revolving field generator. (VI)
6. Explain the operating principles of brushless generators and explain the operating principles and applications of a specific generator. (VII)
7. Explain automatic sequential paralleling and its advantages. (VIII)
8. Explain the National Electrical Code (NEC) requirements that relate to emergency standby systems and for emergency system circuits for light and power. (IX)
9. Identify specific types of welding machines and explain how they operate. (X)
10. Identify the main classifications of arc welding machines and explain specific characteristics of welders including AC/DC, constant potential and constant current. (XI)
11. Setup specific welding equipment. (XII)
12. Explain the NEC requirements for electric welders, weld and install welded cables. (XIII)
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MCCCD Official Course Outline:
 
ABC262   19952-19956 Transformers and Welding Machines
    I. Power Transformer Connections
        A. Wye
        B. Delta
        C. Open delta
      II. Transformers
          A. Basic parts
            1. Primary winding
            2. Secondary winding
            3. iron core
          B. Special transformers - size and install
            1. Multi-secondaries
            2. Auto transformers
            3. Zig-zag grounding transformer
            4. Constant-current transformer
            5. Control transformer
            6. Series transformer
            7. Rectifier transformer
            8. Reactors
            9. Step-voltage regulators
            10. Specialty transformers
        III. Instrument Transformers Purpose
            A. Current transformers
            B. Potential transformers
            C. Buck-and-Boost Transformers
          IV. Standby and Emergency Systems-AC Generators
              A. Alternating current
              B. Operating characteristics
                1. voltage control
                2. load and power factor regulation
            V. Standby emergency electrical Systems
                A. Engine-driven alternators
                  1. Parameters
                  2. Cooling
                  3. Load transfer switch
                B. Shunt field generator with commutator
                C. Shunt field generator with rheostat
                D. Compound generator-DC only
                E. Compound generators-noncranking
                F. Shunt generators-series cranking
                G. DC generator with AC winding
              VI. Revolving Armature Generators and Field Generators
                  A. Electromagnetic field
                  B. AC generator to produce DC
                  C. AC generator excitation
                  D. Voltage regulation
                  E. Voltage regulators
                VII. Brushless Generator/Regulator and Generator Operation
                    A. Voltage wave shapes
                    B. Magnetic excitation
                    C. Exciter field excitation
                    D. Amplifier circuit
                    E. Application
                  VIII. Automatic Sequential Paralleling
                      A. Automatic Transfer Switch
                      B. Advantages
                    IX. NEC Requirements
                        A. Emergency standby systems
                          1. Storage batteries
                          2. Generator sets
                        B. Emergency System Circuits for Light and Power
                          1. Health care facilities (NEC Art. 517-3)
                          2. Places of assembly (NEC Art. 518)
                      X. Welding Machines
                          A. Fundamentals
                            1. Types
                            2. Operation
                          B. Welding Circuits
                            1. Open circuit voltage
                            2. Operating voltage
                        XI. Welding Machine Classifications and Characteristics
                            A. AC
                            B. DC
                            C. AC and DC
                            D. Constant potential
                            E. Constant current
                          XII. Welding Equipment Setup
                              A. Stringing welding cable
                              B. Locating the ground clamp
                              C. Energizing electrically powered welding machines
                            XIII. NEC Requirements for Electric Welders(NEC Arts. 630 and 300- 21)
                                A. AC transformer and DC arc welders
                                B. Motor-generator arc welders
                                C. Resistance welders-overcurrent protection
                                D. Installing welding cables
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