A direct current generator, or DC generator, produces a voltage of constant polarity, which means the voltage and current do not change over time. DC generators are basically AC generators whose output voltage is switched the other way round at the proper moment, so that the direction of the voltage is always in a single direction. The AC generator uses slip rings to transfer the current to the electrical circuit, while the DC generator uses a split-ring commutator. Generators can be very small or quite huge. Commercial DC generators are commonly found in traction applications like subways and trains. Factories that do electrolysis, electroplating and those that produce aluminum, caustic soda, chlorine, and some other industrial materials need large amounts of direct current and use DC generators.An electric motor is very similar to a generator, except that power is provided to turn the rotors. They may, in fact, be described as generators "running backwards". When current is passed through the armature of a DC motor, a torque is generated by magnetic reaction, and the armature revolves. Adjustable speed is difficult to obtain with motors whose armatures are connected to fixed frequency power lines (AC motors). Here is where DC motors shine; their rotating field speed depends on the rotor speed itself. The speed of DC series motors varies with load, and torque varies inversely with speed. This makes them particularly suitable to starting high inertia loads such as railway trains. Starting a DC motor requires often an external resistor or rheostat to limit the current. The value, in Ohms, of that resistor is reduced in steps as the speed of the motor increases, until finally that resistor is removed from the circuit as the motor reaches close to its final speed.This 4-hr Quick Book provides discusses salient features of DC motors and generators in detail. The course is based entirely on Naval Education and Training Materials (NAVEDTRA 14177), Electricity and Electronic Training Series; Module-5 and covers Chapter 1 and 2 titled “Direct Current Generators and Direct Current Motors”. Learning ObjectiveAt the conclusion of this course, the reader will be able to:• State the principle by which generators convert mechanical energy to electrical energy.• State the rule to be applied when you determine the direction of induced emf in a coil.• State what component causes a generator to produce direct current rather than alternating current.• State how field strength can be varied in a dc generator.• State the three classifications of dc generators.• State the term that applies to voltage variation from no-load to full-load conditions and how it is expressed as a percentage.• State the factors that determine the direction of rotation in a dc motor.• State the right-hand rule for motors.• Describe the main differences and similarities between a dc generator and a dc motor.• List the advantages and disadvantages of the different types of dc motors.• Discuss the means of controlling the speed and direction of a dc motor.• Explain the need for a starting resistor in a dc motor.

Direct current machines are a quickly evolving domain whose applications affect many aspects of modern life from computers and printers to toys, electric vehicles, and traction applications. As their many uses continue to grow, it has become apparent that understanding these machines is the key to understanding our future. Operation, Construction, and Functionality of Direct Current Machines brings together many concepts, from the most basic working principles and construction of DC machines to more advanced topics such as electro-magnetism, armature reaction, parallel operations, and many more. Highlighting theoretical concepts and numerical problems, this book is an essential reference source for students, educators, and anyone interested in the field of electric machines.

Tidal Energy Systems: Design, Optimization and Control provides a comprehensive overview of concepts, technologies, management and the control of tidal energy systems and tidal power plants. It presents the fundamentals of tidal energy, including the structure of tidal currents and turbulence. Technology, principles, components, operation, and a performance assessment of each component are also covered. Other sections consider pre-feasibility analysis methods, plant operation, maintenance and power generation, reliability assessment in terms of failure distribution, constant failure rate and the time dependent failure model. Finally, the most recent research advances and future trends are reviewed. In addition, applicable real-life examples and a case study of India's tidal energy scenario are included. The book provides ocean energy researchers, practitioners and graduate students with all the information needed to design, deploy, manage and operate tidal energy systems. Senior undergraduate students will also find this to be a useful resource on the fundamentals of tidal energy systems and their components. - Presents the fundamentals of tidal energy, including system components, pre-feasibility analysis, and plant management, operations and control - Explores concepts of sustainability and a reliability analysis of tidal energy systems, as well as their economic aspects and future trends - Covers the assessment of tidal energy systems by optimization technique and game theory

University Physics is designed for the two- or three-semester calculus-based physics course. The text has been developed to meet the scope and sequence of most university physics courses and provides a foundation for a career in mathematics, science, or engineering. The book provides an important opportunity for students to learn the core concepts of physics and understand how those concepts apply to their lives and to the world around them. Due to the comprehensive nature of the material, we are offering the book in three volumes for flexibility and efficiency. Coverage and Scope Our University Physics textbook adheres to the scope and sequence of most two- and three-semester physics courses nationwide. We have worked to make physics interesting and accessible to students while maintaining the mathematical rigor inherent in the subject. With this objective in mind, the content of this textbook has been developed and arranged to provide a logical progression from fundamental to more advanced concepts, building upon what students have already learned and emphasizing connections between topics and between theory and applications. The goal of each section is to enable students not just to recognize concepts, but to work with them in ways that will be useful in later courses and future careers. The organization and pedagogical features were developed and vetted with feedback from science educators dedicated to the project. VOLUME II Unit 1: Thermodynamics Chapter 1: Temperature and Heat Chapter 2: The Kinetic Theory of Gases Chapter 3: The First Law of Thermodynamics Chapter 4: The Second Law of Thermodynamics Unit 2: Electricity and Magnetism Chapter 5: Electric Charges and Fields Chapter 6: Gauss's Law Chapter 7: Electric Potential Chapter 8: Capacitance Chapter 9: Current and Resistance Chapter 10: Direct-Current Circuits Chapter 11: Magnetic Forces and Fields Chapter 12: Sources of Magnetic Fields Chapter 13: Electromagnetic Induction Chapter 14: Inductance Chapter 15: Alternating-Current Circuits Chapter 16: Electromagnetic Waves

Majors and non-majors in electricity will benefit from this easy-to-understand and highly illustrated introduction to DC and AC electrical theory, circuits, and equipment. The only prequisites are algebra and a basic knowledge of trigonometry. This updated edition reflects changes in industry resulting from increasing computerization of electrical equipment. Modern solid-state components are covered in appropriate sections throughout the book. These components are especially featured in the area of industrial controls.

Offshore Electrical Engineering Manual, Second Edition, is for electrical engineers working on offshore projects who require detailed knowledge of an array of equipment and power distribution systems. The book begins with coverage of different types of insulation, hot-spot temperatures, temperature rise, ambient air temperatures, basis of machine ratings, method of measurement of temperature rise by resistance, measurement of ambient air temperature. This is followed by coverage of AC generators, automatic voltage regulators, AC switchgear transformers, and programmable electronic systems. The emphasis throughout is on practical, ready-to-apply techniques that yield immediate and cost-effective benefits. The majority of the systems covered in the book operate at a nominal voltage of 24 y dc and, although it is not necessary for each of the systems to have separate battery and battery charger systems, the grouping criteria require more detailed discussion. The book also provides information on equipment such as dual chargers and batteries for certain vital systems, switchgear tripping/closing, and engine start batteries which are dedicated to the equipment they supply. In the case of engines which drive fire pumps, duplicate charges and batteries are also required. Packed with charts, tables, and diagrams, this work is intended to be of interest to both technical readers and to general readers. It covers electrical engineering in offshore situations, with much of the information gained in the North Sea. Some topics covered are offshore power requirements, generator selection, process drivers and starting requirements, control and monitoring systems, and cabling and equipment installation - Discusses how to perform inspections of electrical and instrument systems on equipment using appropriate regulations and specifications - Explains how to ensure electrical systems/components are maintained and production is uninterrupted - Demonstrates how to repair, modify, and install electrical instruments ensuring compliance with current regulations and specifications - Covers specification, management, and technical evaluation of offshore electrical system design - Features evaluation and optimization of electrical system options including DC/AC selection and offshore cabling designs