Maricopa Community Colleges  FAC115   19986-19995 
Official Course Description: MCCCD Approval: 04/28/98
FAC115 19986-19995 LEC 3 Credit(s) 3 Period(s)
Motors, Controls and Wiring Diagrams
Principles of three-phase motors. Wye and Delta wiring. Calculation of motor current draw. Sequence of operation, wiring diagram and electrical components of residential heating and cooling equipment. Procedures for evaluating electrical problems. Safety stressed. Prerequisites: HVA105, or permission of department, or HVA105LL, or permission of department. Corequisites: HVA115LL or permission of department.
Cross-References: HVA115
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MCCCD Official Course Competencies:
 
FAC115   19986-19995 Motors, Controls and Wiring Diagrams
1. Explain principles of operation for three phase motors. (I)
2. Identify Wye and Delta types of wiring diagrams and explain high/low voltage for each. (II)
3. Explain the terms "synchronous speed " and major factors determining amounts of induced voltage into rotors. (III)
4. Explain the function of torque and how it is produced in motors. (IV)
5. Using the data on motor nomenclature plates and the National Electrical Code (NEC), calculate motor current draw. (V)
6. Explain the operation of specific controls in residential air conditioning and heating pumps including thermostats, low pressure/high pressure switches, defrost control systems and reversing valves. (VI)
7. Translate residential heating/cooling equipment line wiring diagrams to ladder diagrams. (VII)
8. Given electrical components representing specific heating/cooling systems, write sequences of operations. (VIII)
9. Draw ladder diagrams into line diagrams for designing control panels. (IX)
10. Using the theory of electrical circuits, write a procedure for evaluating electrical problems, including appropriate safety procedures. (X)
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MCCCD Official Course Outline:
 
FAC115   19986-19995 Motors, Controls and Wiring Diagrams
    I. Three Phase Motors
        A. Operation
        B. Types (rotors)
          1. squirrel cage
          2. wound rotor
          3. synchronous
        C. Field factors
          1. voltage phase angle
          2. change in polarity
          3. arrangement of stator windings
      II. Motor Wiring Diagrams
          A. Wye
            1. high voltage
            2. low voltage
          B. Delta
            1. high voltage
            2. low voltage
          C. Twelve lead motors
          D. Direction change
        III. Synchronous Speed and Voltage Induction
            A. Definitions
            B. Factors for induction
              1. strength of field
              2. turns of wire
              3. speed
          IV. Motor Torque
              A. Major factors
                1. strength of magnetic field - starter
                2. strength of magnetic field - rotor
                3. phase angle of currents
              B. Load effects
              C. Phase angle - maximum torque
              D. Function
            V. Code Letters and Current Draw
                A. Types of rotors
                B. NEC tables
                C. Calculations
              VI. Air Conditioning/Heat Pump Controls
                  A. Types/operation
                    1. thermostat
                    2. low pressure switch
                    3. high pressure switch
                    4. defrost control systems
                    5. reversing valves
                  B. Purposes
                  C. Relationships
                VII. Wiring Diagrams
                    A. Pictorial
                    B. Line
                  VIII. Wiring Diagram Development
                      A. Components
                      B. Sequence of operation
                      C. Diagramming
                    IX. Ladder/Line Diagrams - Control Panels
                        A. Component location
                        B. Terminal identification
                        C. Wire numbering
                        D. Illustrating
                      X. Electrical Circuit Evaluation Procedure
                          A. Electrical theory
                          B. System type
                          C. Operating sequence
                          D. Procedure
                            1. electrical supply
                            2. operating loads
                            3. non-operating loads
                            4. sequence
                            5. safety
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