Industrial Electricity Vol 2
Course Number: 8174
The Industrial Electricity Vol. 2 textbook assumes a basic knowledge of the principles of electricity and focuses on the principles of three-phase circuits and motors and continues with its industry validated approach by concluding with a thorough and comprehensive explanation of electrical troubleshooting that may occur in the industrial workplace.
Recommended Contact Hours – 23
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Table of Contents
Chapter 1: Principles of Three-Phase Circuits
Topics: Three-phase alternators; Y- and delta-connected alternators; Power in three-phase circuits; Load connections; Measuring power
- List the main advantages of the three-phase ac system.
- State the definition of phase sequence.
- Demonstrate how to calculate the RMS power in a single-phase circuit.
- Explain how to measure the total power consumed by the load in a three-phase circuit.
- List the functions of an instrument transformer.
Chapter 2: Transformer Operations
Topics: Transformer designation, insulation, cooling, and polarity; Single-and three-phase transformer connections; Installing transformers
- Name general kinds of transformers.
- List the temperature limits for each class of transformer insulation.
- Explain how oil-immersed transformers are cooled.
- Name the common methods of connecting three single-phase transformers for threephase operation.
- Explain how to select the correct location for a transformer.
Chapter 3: Principles of Three-Phase Motors
Topics: Induction motors; Squirrel-cage rotors; Pole-phase relationships; Torque, rotor speed, slip, frequency, resistance, reactance, and power factor
- Describe a squirrel-cage rotor.
- List the factors that determine the strength of the magnetic field in an induction motor.
- Discuss pole-phase relationships.
- Demonstrate how to reverse the rotation direction of the magnetic field.
- Discuss the relationship between rotor speed and frequency.
Chapter 4: Maintaining Three-Phase Motors
Topics: Cleaning; Care of stator and rotor windings; Air gap; Overload and single-phase operation; Motor shaft currents; Bearings; Maintenance schedule
- List the steps in measuring the resistance of the insulation on motor windings.
- Explain how to raise the temperature of a motor winding.
- List the steps in lubricating motor bearings.
- List the conditions that must exist before you can lubricate bearings.
Chapter 5: Three-Phase Motor Controllers
Topics: Limitations; Full-voltage and across-the-line starting; Reducing starting current; Primary- and secondary-resistance starters; Maintenance; Multiple start-stop controls; Across-the-line reversing starters; Plugging control; Jogging; Controlling surge and backspin
- Explain how a motor starter works.
- Explain the difference between open transition and closed transition.
- Name the common kinds of reduced-voltage starters.
- List the steps in inspecting motor starters.
- Explain how to select the best motor starter for a particular application.
- Explain the difference between low-voltage release and low-voltage protection.
- Describe the plugging process.
- Explain how to prevent backspin.
Chapter 6: Motor Starters
Topics: Motor controllers; Controller enclosures; Starters; Magnetic controls; Interlocks, Reversing and combination starters
- Describe the difference between a manual starter and a magnetic starter.
- Explain the function of a shading coil in a magnetic starter.
- Explain the effects of low voltage on a controller.
- State the reason why holding-circuit interlocks are required on magnetic starters and contactors.
- Demonstrate how to reverse the shaft rotation of a three-phase motor.
Chapter 7: Switches and Controls
Topics: Pushbuttons; Selector switches; Wall boxes; Contact blocks; Indicating lights; Circuit diagrams; Legend plates
- Discuss the characteristics of industrial switches and controls.
- Identify the five most commonly used NEMA pushbutton stations.
- Demonstrate how to mount an oil-tight control station both vertically and horizontally.
- Explain the difference between standard and press-to-test indicating lights.
- Explain how a three-wire control circuit works.
Chapter 8: Control Relays
Topics: Contact operation; Mountings, enclosures, terminals, and definitions; NEMA classes; Causes of failure
- State the definition of a relay
- Explain the function of relay contacts.
- Select the best relay for use where large movement of the contacts or high contact force is required.
- List the advantages of a reed relay.
- Tell why industrial relays usually have double-break contacts.
Chapter 9: Motor Control Centers
Topics: Features and advantages; MCC bus; NEMA standards; Enclosure construction; Wiring; Circuit protection; Installation
- Define the term motor control center.
- Name the main advantages and disadvantages of back-to-back MCC construction.
- Explain how to install an MCC.
- Define a note, a caution, and a warning as each relates to MCC equipment.
- List the checks to conduct prior to releasing an MCC for plant operation.
Chapter 10: Troubleshooting with Electrical Schematics
Topics: Symbols; Elementary diagrams; Power control and motor-starting circuits; Identifying conductors; Control panel layout; Sequence of operation
- Identify a control relay on an electrical schematic.
- State the NEC requirements for fuses in ungrounded conductors.
- Explain component numbering on electrical schematics.
- Explain how conductors in a motor-control circuit are identified.
Chapter 11: Troubleshooting Control Circuits
Topics: Control-circuit functions; Conditions of protection; Troubleshooting pushbutton, sequence/control, motor, and overload circuits
- Explain how severe three-phase voltage unbalance affects a three-phase motor.
- List the advantages of inherent protection.
- Explain how undervoltage release works.
- Describe how to troubleshoot a motor circuit.
Chapter 12: Troubleshooting Combination Starters
Topics: Using relay-troubleshooting charts; Latching-relay and timing-relay checks; Replacing relay coils; Troubleshooting control circuits, starters, and relays
- List the reasons why a magnet coil burns or short-circuits.
- List the steps in troubleshooting a defective motor.
- Explain how a mechanical latching relay works.
- Explain how an electronic timing relay operates.
Chapter 13: Troubleshooting Control Devices
Topics: Reversing controllers; Using a checking-sequence chart; Autotransformer starters; Multispeed motor starter controls
- Demonstrate how to reverse the rotation of a three-phase induction motor.
- Explain the function of limit switches in reversing-motor applications.
- Describe how to use a checking-sequence chart.
- Select the best starter for use where it is undesirable to put a heavy load on the power supply.
- Explain how to change the speed of a squirrel-cage motor.
Chapter 14: Troubleshooting Special Controls
Topics: Selenium rectifiers; Testing rectifier diodes and three-phase rectifiers; Control-system logic; Static control; Time delay element
- Explain the effects of age on a selenium rectifier.
- Name the protective devices used in electrical systems and pneumatic systems.
- State the definition of a bistable device.
- List the functions of a static control device.
Chapter 15: Troubleshooting AC Motors
Topics: Grounded stator windings; Short-circuited and reversed phases; Open circuits; Incorrect voltage connections
- Identify various kinds of three-phase motor failures.
- Demonstrate how to conduct a balanced-current test on a three-phase, Y-connected winding.
- List the symptoms of a reversed phase in a three-phase winding.
- Explain how to identify external leads that have become defaced.
- Demonstrate how to test for an open circuit in a split-phase motor
Add Chapters to Your Custom Book
- Chapter 1: Principles of Three-Phase Circuits
- Chapter 2: Transformer Operations
- Chapter 3: Principles of Three-Phase Motors
- Chapter 4: Maintaining Three-Phase Motors
- Chapter 5: Three-Phase Motor Controllers
- Chapter 6: Motor Starters
- Chapter 7: Switches and Controls
- Chapter 8: Control Relays
- Chapter 9: Motor Control Centers
- Chapter 10: Troubleshooting with Electrical Schematics
- Chapter 11: Troubleshooting Control Circuits
- Chapter 12: Troubleshooting Combination Starters
- Chapter 13: Troubleshooting Control Devices
- Chapter 14: Troubleshooting Special Controls
- Chapter 15: Troubleshooting AC Motors
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