Maricopa Community Colleges  ABC221   19952-19966 
Official Course Description: MCCCD Approval: 11/22/94
ABC221 19952-19966 L+L 3 Credit(s) 6 Period(s)
Motors and Motor Controls
Electrical symbols, line diagrams and logic. Contactors and starters, control devices, reversing circuits and power distribution systems. Electronic control devices, programmable controllers, reduced voltage starters, accelerating and decelerating methods and circuits. Preventive maintenance and trouble shooting. 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:
 
ABC221   19952-19966 Motors and Motor Controls
1. Read and interpret line diagrams. (I)
2. List differences between electrical solenoids, contactors and magnetic motor starters. (II)
3. Explain the difference between a manual contactor and a manual starter. (III)
4. List the major differences between an AC and DC contactor and explain why arc suppression is used with AC and DC contactors and starters. (IV)
5. List specific types of motor overload protection and primary factors used in selecting the proper type of protection. (IV)
6. Name the main parts of limit switches and the common types of actuators used with them. (V)
7. Explain how to get the pressure differential on a pressure switch and list specific ways of actuating temperature switches. (V)
8. Explain the difference between a 3 phase Wye and 3 phase Delta motor. (VI)
9. List the major functions of a substation, specific categories of switchboards and primary classifications of panelboards. (VII)
10. Identify the parts of a Programmable Controller (PC) board. (VIII)
11. Explain semiconductor theory and how it relates to specific semiconductor devices. (VIII)
12. Describe scanning techniques used in photoelectric applications and explain the function of the sensitivity adjustment on a photo eye. (IX)
13. Describe the major advantages of using programmable controllers and list specific application areas. (X)
14. List specific reasons for using reduced voltage starting, the five methods used in reduced voltage starting and one advantage and one disadvantage for specific braking methods. (XI)
15. List main categories of motor applications, demonstrate how to control the speed of AC and DC motors and identify accelerating and decelerating circuit logic when applied to a speed control circuit. (XII)
16. List the necessary components of preventive maintenance and troubleshooting programs. (XIII)
17. List the basic rules for using test instruments, test a fuse on the CB in a circuit and test a control transformer for an open, a ground or a short. (XX)
18. Remark a 3 phase or DC motor, locate a circuit in a switchboard, test for an open or shorted capacitor and test for a good diode or SCR. (XIII)
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MCCCD Official Course Outline:
 
ABC221   19952-19966 Motors and Motor Controls
    I. Line diagrams and logic
        A. Line diagrams
          1. Lines
          2. Symbols
          3. Power source
          4. Current flow
        B. Logic
          1. Rules
          2. Sections
          3. Functions
      II. Magnetic control devices
          A. Solenoids
          B. Contactors
          C. Magnetic motor starters
        III. AC manual contactors and motor starters
            A. Knife switch disadvantages
              1. Electrical hazard to operator
              2. Slow speed
              3. Short service life
            B. Line diagram vs. wiring diagram
              1. Realistic detail
              2. Complexity
            C. Manual contactors vs. manual starters
              1. Fuse
              2. Overload protection device
            D. Overload protection
              1. Starting current
              2. Overloaded running current
            E. AC manual contactor categories
              1. Single-phase
              2. Three-phase
            F. Fuse protection
              1. 115%
              2. 125%
            G. Enclosures (NEMA)
              1. Surface mounted
              2. Flush mounted
              3. Indoor
              4. Outdoor
              5. Hazardous locations
              6. Water resistant
          IV. Contactors and magnetic motor starters
              A. Contactor types
                1. Electronic
                2. Magnetic
              B. Contactor wiring
                1. Two wire
                2. Three wire
              C. AC vs. DC contactors
              D. Arc suppression
              E. Overload protection devices
                1. Melting alloy overload relay
                2. Magnetic overload relay
                3. Bi-metallic automatic reset overloads
              F. Overload protection factors
                1. Motor characteristics and surroundings
                2. Full-load current rating
                3. Service factor
              G. Optional modifications for contactors and magnetic motor starters
                1. Additional electrical contacts
                2. Power poles
                3. Pneumatic timer
                4. Transient suppression module
                5. Control circuit fuse holder
            V. Control devices
                A. Push buttons (parts)
                  1. Contact blocks
                  2. Legend plates
                  3. Operators
                B. Push buttons (operations)
                  1. On (start)
                  2. Off (Stop)
                  3. Jog
                  4. Reset
                  5. Run
                C. Target (truth) tables
                D. Limit switches (parts)
                  1. Actuating mechanisms
                  2. Contacts
                E. Pressure switches - pressure differential
                F. Temperature switches - actuation
                  1. Bi-metallic controls
                  2. Capillary tube control
                  3. Thermocouple control
                  4. Solid state temperature control using a thermocouple
                G. Float switches
                H. Logic modules
              VI. Reversing circuit - three phase motors
                  A. Wye
                  B. Delta
                  C. Reversing
                  D. Interlocking
                    1. Mechanical
                    2. Auxiliary contact
                    3. Pushbutton
                VII. Power distribution systems
                    A. Alternators (main source of electrical energy)
                    B. Transformers
                      1. Wye connection
                      2. Delta connection
                    C. Substation functions
                      1. Receive and increase voltage
                      2. Receive and reduce voltage
                      3. Provide safe disconnection point
                      4. provide adjustment and regulation of voltage
                      5. Switching point
                    D. Switchboard categories
                      1. Service entrance
                      2. Distribution
                      3. Combination
                    E. Panelboards
                      1. Lighting and appliance
                      2. Power
                      3. Distribution
                    F. Motor control centers
                    G. Busways
                      1. Feeder type
                      2. Plug in type
                    H. Grounding
                  VIII. Sold state electronic control devices
                      A. PC board
                        1. Pads
                        2. Traces or foils
                        3. Bus
                        4. Edge card
                        5. Edge card connector
                      B. Semiconductor theory
                      C. N type material
                      D. P type material
                      E. Rectification of AC
                        1. Single phase
                        2. Three phase
                      F. Zener diode
                      G. Photovoltaic cell
                      H. Light emitting diodes (LED)
                      I. Transistors
                        1. Type
                        2. Operation
                      J. Silicon controlled rectifier (SCR)
                      K. Electronic signals
                        1. Analog
                        2. Digital
                      L. Gates in digital electronics
                        1. AND
                        2. OR
                        3. NAND
                        4. NOR
                      M. Fiber optics
                        1. Use
                        2. Advantages
                    IX. Photoelectric applications
                        A. Scanning techniques
                          1. Direct scan
                          2. Reflective scan
                          3. Retroreflective scan
                          4. Polarized scan
                          5. Convergent beam
                        B. Sensitivity adjustment
                        C. Light source
                          1. Light operated
                          2. Dark operated
                        D. Hall effect sensors
                          1. Types
                          2. Actuation
                      X. Programmable controllers
                          A. Advantages
                            1. Programmable and reprogrammable
                            2. Reduced wiring costs
                            3. Reduced space requirements
                            4. Flexible control
                            5. High reliability
                          B. Application
                            1. Parts manufacturing
                            2. Process manufacturing
                          C. Advantages of programmable controllers vs. computers
                            1. Direct communication
                            2. Ease in programming
                            3. Designed for industrial use
                          D. Parts and their functions
                            1. Power supply
                            2. Input/output interface sections
                            3. Processor section
                            4. Programming section
                          E. Discrete vs. data inputs and outputs
                          F. Program development
                            1. Create line diagrams
                            2. Convert to programming diagram
                            3. Enter desired logic
                            4. Enter written program
                          G. Multiplexing-advantages
                            1. Eliminates costly hardwiring
                            2. Simpler than hardwiring
                            3. Expandable
                            4. Transmits analog and digital signals
                            5. Clock and printer for documentation
                        XI. AC reduced voltage starters
                            A. Reasons for use
                              1. Power source
                              2. Torque and starting requirements/methods
                              3. Electrical environment
                            B. Methods used
                              1. Primary resistor
                              2. Auto transformer
                              3. Part-winding
                              4. Wye-Delta
                              5. Solid-state
                          XII. Accelerating and decelerating
                              A. Braking methods
                                1. Friction brakes
                                2. Plugging
                                3. Electrical braking
                                4. Dynamic braking
                              B. Braking torque determination
                              C. Motor applications
                                1. Residential
                                2. commercial
                                3. Industrial
                              D. Speed control
                                1. AC motors
                                2. DC motors
                              E. Speed control circuit logic
                                1. Accelerating
                                2. Decelerating
                            XIII. Preventive maintenance and troubleshooting
                                A. Preventive maintenance
                                  1. Inspection
                                  2. Cleaning
                                  3. Tightening
                                  4. Adjusting and lubrication
                                  5. Keeping equipment dry
                                B. Troubleshooting
                                  1. Test instrument use
                                  2. Fuse testing
                                  3. Control transformer testing
                                  4. Motor failure
                                  5. Remarking 3 phase or DC motors
                                  6. Locating switchboard circuits
                                  7. Checking capacitors
                                  8. Testing diodes and SCRs
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