Standard |
ELT 112 - Variable Speed/Low Voltage
Controls
Introduces types of electric motor control, reduced voltage starting, and applications. Emphasis will be placed on motor types, controller types, and applications. Includes information on wye and delta motor connections; part wind, autotransformer; adjustable frequency drives and other applications; and oscilloscopes and their operation. Topics include: motor controls, types of reduced voltage starting, reduced voltage motor connections, adjustable frequency drive, and oscilloscope operations.
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Competency Areas |
Hours
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Motor Controls |
Class |
3 |
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Types of Reduced Voltage Starting |
D. Lab |
0 |
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Reduced Voltage Motor Connections |
P. Lab/O.B.I. |
6 |
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Adjustable Frequency Drive |
Credit |
5 |
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Oscilloscope Operations |
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Prerequisite/ Corequisite: |
ELT 111 |
Course Guide |
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Competency |
After completing this section,
the student will: |
Hours |
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Class |
D. Lab |
P. Lab/ O.B.I. |
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MOTOR CONTROLS |
2 |
0 |
12 |
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Fundamentals |
Describe the fundamentals of motor controls. |
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Application |
Describe motor control circuit design and installation. |
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TYPES OF REDUCED VOLTAGE STARTING |
8 |
0 |
12 |
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Primary resistance starters |
Diagram the primary resistance starter and motor connections and wiring. |
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Auto-transformer starters |
Diagram the auto-transformer starter and motor connections and wiring. |
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Wye-delta starters |
Diagram the wye-delta starter and motor connections and wiring. |
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Solid state starters |
Diagram the solid state starter and motor connections and wiring. |
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REDUCED VOLTAGE MOTOR CONNECTIONS
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10 |
0 |
12 |
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Primary resistance starters |
Install and operate a primary resistance controller and connected motor. |
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Auto-transformer starters |
Install and operate an auto-transformer controller and connected motor. |
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Wye-delta starters |
Install and operate a wye-delta controller and connected motor. |
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Solid state starter |
Install and operate a solid state controller and connected motor. |
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ADJUSTABLE FREQUENCY DRIVE |
5 |
0 |
12 |
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Power supply |
Describe the use of an adjustable speed activator with an induction motor. |
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Describe the use of frequency connectors with an induction motor. |
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Describe the applications of a speed regulator and volts per cycle regulator. |
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Speed control |
Describe how the Leblanc, Karmer, and Scherbius systems or speed control feed rotor power back in the line or provide additional motor torque. |
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Modified frequency |
Use the formula:F=Required Rev.Min x No. of piles to obtain modified frequency. |
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OSCILLOSCOPE OPERATIONS |
5 |
0 |
12 |
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Oscilloscope operation |
Identify procedures for testing electrical circuits with an oscilloscope. |
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Identify RC and RL circuits using an oscilloscope. |
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Suggested Resources |
Adams, J., & Rockmaker,
G. (1985). Industrial electricity:
Principles and practices (3rd ed.). New York: McGraw-Hill.
Baitch, T. (1984). Electrical technology. New York: John
Wiley & Sons.
Bloch, H. P., &
Geirner, F. K. (1985). Machinery
component maintenance and repair. Houston, TX: Gulf Publishing.
Court, M. (1988). Lab manual for first course in electrical
technology. New York: John Wiley & Sons.
Hughes, E. (1987). Electrical technology (6th ed.). New
York: John Wiley & Sons.
Langley, B. C. (1985).
Plant maintenance. Reston, VA:
Reston.
Office of Personnel
Management. (1988). Industrial equipment
mechanic. Syosset, NY: Natl Learning.
Schram, P. J., & Murray, R. H. (1987). The national electrical code (4th ed.).
Quincy, MA: National Fire Protection Association.