Motor Controls CGTCMOTORCONT01

Transcription

1 Motor Controls CGTCMOTORCONT01 Course Description: Central Georgia Technical College provides a 300 hour Industrial Motor Control Level (1&2 combined) training course. The first (150 hour) part of the course introduces the fundamental concepts, principles, and devices involved in industrial motor controls, theories and applications of single and three-phase motors, wiring motor control circuits, and magnetic starters and braking. This second (150 hours) part of the course introduces the theory and practical application for two-wire control circuits, advanced motor controls, and variable speed motor controls. Emphasis is placed on circuit sequencing, switching, and installation, maintenance, and troubleshooting techniques. The emphasis in this course is designed to meet the needs of RAFB 5350 production machinery mechanics. The following topics are covered: First part: Industrial Safety, Motor Theory and Operating Principles, Principles of Motor Controls, Control Devices, Symbols and Schematic Diagrams, Magnetic Starters and Braking, NEMA Standards, Article 430 NEC and Preventative Maintenance and Troubleshooting. Second part: Two Wire Control Circuits, Advanced Motor Controls, Variable Speed Motor Controls, Troubleshooting Advanced Industrial Motor Controls, Semiconductor Fundamentals, and Diodes Applications. Prerequisite: None Instructor to student ratio: 10 to 1 Training Syllabus: Motor Controls Course (CGTCMOTORCONT01) Part I. 1. Overview Of Safety a. Importance of adherence to all shop safety requirements. b. Observe all proper safety precautions to prevent personal injury or equipment damage. c. Aware of all the hazards associated with working on equipment and using special tools. d. Know Lockout/Tagout procedures e. Wear proper PPE. 2. Motor Theory and Operating Principles a. Describe the laws of magnetism and their application to AC and DC motors. b. Compare the operating principles of AC motors with those of DC motors. c. Compare the characteristics of AC motors with those of DC motors. d. Define terms associated with electric motors e. Identify the component parts of an electric motor. f. Name different types of AC and DC motors.

2 g. Determine voltage, amperage, speed, horsepower, NEMA class, and environmental requirements of electric motors using data from the motor name plate. 3. Principles of Motor Controls a. Name the three classes of DC motors. b. Describe the operating characteristics of the three classes of DC motors. c. Identify the components of DC motors. d. State the function of starter devices in DC motors. e. Name the types of manual DC motor starters f. Identify the components used in DC motor control. g. Name the types of automatic DC motor starters. h. Describe the methods of controlling the speed of DC motors. i. Name the three classes of AC motors. j. Describe the operating characteristics of the three classes of AC motors. k. Identify the components of AC motors. l. State the purpose of controllers in AC motor circuits. m. Name the types of AC motor controllers. n. Identify the components used in AC motor controls. o. Describe the methods used to provide circuit protection in AC motor control applications. 4. Control Devices a. Identify and describe various devices used for sensing temperature, pressure, level, motion, and position. b. Identify and describe the devices used in switching circuits. c. Identify and describe the devices used for motor overload protection. d. Identify and describe the devices used for ground fault and short circuit protection. e. Identify and describe various other devices used in motor control circuits. 5. Symbols and Schematic Diagrams a. Identify and draw the various symbols for components and conditional state of devices used in motor control circuits. b. Describe a typical motor control schematic diagram. c. Draw a schematic diagram of a motor control circuit. d. Interpret schematic diagrams of various motor control circuits. 6. Magnetic Starters and Braking a. Wire control transformers for the various 24V, 120V, and 230V secondary control voltages used in the industry. b. Wire an across-the-line motor starter using a start-stop switch. c. Wire a forward/reverse motor starter using a stop/forward/reverse switch.

3 d. Wire a magnetic starter for a motor control using a run/jog/stop switch without a control relay. e. Wire a magnetic starter for a motor control using a control relay and a run/jog/stop switch. f. Identify and describe the different dynamic, plugging, electronic, electric, and manual types of motor braking devices used in the industry. g. Install a braking system on a motor. 7. NEMA Standards a. Identify the purpose of NEMA standards for electric motors. b. Relate NEMA design codes to operating characteristics of electric motors. c. Describe NEMA standards for types of electric motor enclosures. 8. Article 430 NEC a. Calculate the size for branch circuit conductors covered by NEC selection b. Calculate the size for feeder circuit protection covered by NEC section c. Calculate the size for ground fault/short circuit protection (fuses and circuit breakers) using locked motor current, Table , and Article of the NEC. d. Calculate the size of overload protection according to sections and of the NEC. e. Size equipment grounds according to Table of the NEC. f. Size and locate the motor disconnects according to NEC Part H, Article 430. g. Size controllers according the NEMA standards. h. Calculate the size of control conductors according to Article of the NEC. i. Size raceways for motor circuits using Chapter 9: Table 3A, 3B, 3C, 4, and 5 of the NEC. 9. Preventative Maintenance and Troubleshooting a. Perform a visual inspection using procedures described in the manufacturer's service manual. b. Lubricate a motor according to procedures described in the manufacturer's service manual. c. Clean a motor according to procedures outlined in the manufacturer's service manual. d. Discuss techniques for troubleshooting electric motors. 10. Laboratory Safety Procedures and Practices a. Review general safety standards for working with electrical components in the laboratory. b. Identify and discuss the potential safety hazards and precautions of working with specific electric motors and controlling devices.

4 Part II. 1. Two Wire Control Circuits a. Install a motor control limit switch to control magnetic starters. b. Adjust a motor control limit switch for proper operation. c. Install a motor control proximity switch in a control circuit to detect the presence of metal. d. Install a motor control proximity switch for use as a motion detector. e. Calibrate a motor controller proximity switch for sensitivity. f. Install a pressure switch to control a magnetic starter of a motor controller. g. Adjust the range and differential settings for given pressure limits of a motor controller. h. Install a motor controller temperature switch to control a heating element. i. Adjust a motor controller temperature switch for a given range of temperature. j. Install a motor controller float switch to operate a pump. k. Adjust a motor controller float switch for given operating levels. l. Install a motor controller photo switch in a control circuit to detect the presence of light. m. Install a motor controller photo switch for use as a light detector. n. Calibrate a motor controller photo switch for sensitivity. 2. Advanced Motor Controls a. Identify the various types of timers used in motor control circuits. b. Operate on-delay timers for applications in motor control circuits. c. Operate off-delay timers for applications in motor control circuits. d. Install a time delay relay for use in a motor control circuit. e. Adjust the time on a time delay relay used in a motor control circuit. f. Install a time delay relay and two magnetic starters to sequence the operation of two motors. g. Install and operate a primary resistance starter motor controller. h. Install and operate an auto-transformer starter in a motor control circuit. i. Install and operate a wye-delta starter in a motor control circuit. j. Install and operate a solid state starter in a motor control circuit. k. Install various motor control components in a motor control center. 3. Variable Speed Motor Controls a. Cite industrial applications of variable speed motor control circuits. b. Define the parameters, torque, acceleration, deceleration, p.w.m., frequency, voltage/hertz ratio, boost, I.R. compensation, and high bus fault as applicable to variable speed motor controllers. c. Describe how an AC frequency drive operates to vary motor speed. d. Install an AC frequency drive to control motor speed. e. Setup and calibrate an AC frequency drive to adapt to changing parameters.

5 f. Determine the interconnections needed for various AC motor speed applications on two speed motors. g. Describe the relationships of torque and speed to series, shunt, and compound DC motors. h. Diagram an armature rheostat variable speed circuit for DC motors. i. Diagram compound variable speed DC motors. j. Describe the methods used to obtain variable speed control of compound DC motors. k. Install a DC variable speed drive for a DC motor. l. Calibrate a DC variable speed drive for a DC motor. m. Select the appropriate control cabinet for a variable speed motor control circuit. n. Sketch floor plans for the installation of variable speed motor control systems. o. Sketch the layout of electrical accessories and conductors used in variable speed motor control circuits. p. Install components, wire control cabinets, operator's stations, and motors for variable speed DC and AC motor control circuits. q. Explain the formulas for determining the synchronous speed of AC motors. r. Diagram a bank of starters used to achieve speed ranges for AC motors. s. Sketch circuits which use mechanical interlocks for starters in AC motor variable speed controllers. t. Sketch circuits which use auxiliary contacts for interlocks between starters in AC motor variable speed controllers. u. Sketch circuits which use pushbuttons for interlocks between starters in AC motor variable speed controllers. v. Describe the timing factors of speed ranges for variable speed DC motor controllers. w. Evaluate the use of DC motor and variable speed controllers in specific industrial applications. 4. Troubleshooting Advanced Industrial Motor Controls a. Use proper troubleshooting techniques to eliminate problems in motor control systems. b. Use a VOM to troubleshoot a motor control circuit and diagnose the problems. c. Use motor controller schematic diagrams, a VOM, test terminals, and terminal strips to locate and diagnose problems at motor control centers. 5. Semiconductor Fundamentals 6. Diodes Applications