Standard
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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: types of reduced voltage starting, reduced voltage motor connections, and adjustable frequency drive.
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Competency Areas: |
Hours: |
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Types of Reduced Voltage Starting |
Class |
2 |
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Reduced Voltage Motor Connections |
D. Lab |
0 |
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Adjustable |
P. Lab/O.B.I. |
3 |
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Credit |
3 |
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Prerequisite/Corequisite:
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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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TYPES OF REDUCED VOLTAGE STARTING |
7 |
0 |
10 |
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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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8 |
0 |
10 |
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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
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5 |
0 |
10 |
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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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Suggested Resources
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Hart; Ugly’s Electrical References, Burleson Distribution Corp. ISBN 0-9623229-6-2
Rosenberg,
Robert,; Electrical
Motor Repair (3rd ed.), Delmar
Publishers, ISBN 0-03-059584-3
Rockis/Mazur, Electric Motor Controls (2nd ed.), American Technical Publishers ISBN 0-8269-1675-9
Rockis/Mazur, Electric Motor Controls Workbook (2nd ed.), American Technical Publishers ISBN 0-8269-1676-7
Static Control Training System Concepts of AC Machine Control Volume 2, The staff of Buck Engineering Co. Inc., Lab-Volt Publishers ISBN tm-15783a
Static Control Training System Concepts of DC Motor Control volume 3, The staff of Buck Engineering Co. Inc., Lab-Volt Publishers ISBN tm-15784
Electric Motor Control 1 Lap 12 and 13 Package, Published by Amatrol, ISBN 17403
Electric Motor Control 1 Lap 14, Published by Amatrol, ISBN 17404
Electric Motor Control 2 Lap Package, Published by Amatrol, ISBN 17411
Electric Motor Control 2 Lap
5, Published by Amatrol, ISBN 17412.