A Pragmatic Approach for Comparative Analysis of Linear and Rotary Generators
ABSTRACT
This paper identifies the need for consolidating analysis techniques for the purpose of designing linear electrical generation systems. Additionally, it identifies a need for concise system development tools that help designers make practical comparisons between linear and rotary machines.
INTRODUCTION
The basic principles for converting mechanical energy to electrical energy have been known for over a century. It would seem that after this much time, advancements in electrical generation should have reached their limits; however, up to the late 1980’s and early 90’s the use of linear generators for the generation of electricity has not been seriously considered [1] [4].
Linear generators and motors are classified as linear motion electromagnetic systems (LMESs) [1]. LMESs that are used as electric generators function by directly utilizing the translational (back and forth or up and down) thrust from mechanical systems to generate electricity as opposed to the more conventional generation approach of rotational mechanical energy conversion.
For an engineer to determine the feasibility of using a linear electric generator in a system’s design many comparisons between rotary and linear machines must be made. Several points to consider when making this comparison include: practicality of using linear power generation for that particular system, cost to build and design, total system efficiency, role of modern day power electronics, type of driving force (linear or rotational) applied to the generator system, system power factor, force density and force ripple on the drive components, cost to maintain, and the system’s reliability. The relative weights of these considerations will vary from one system to the next. The motivation behind this question was the decision on whether to use a linear or rotary generator on a buoy driven, ocean wave electrical generator project [6]. During this decision process, many opinions and assumptions between these competing systems were made, but finding hard data that compared the two methods was not readily available. Taking the time to thoroughly evaluate the electrical and mechanical technical aspects of this choice (rotary vs. linear) conflicted with the tight scheduling requirements of the project. This situation forced the team to make a best approximation based on limited experience instead of a deliberate and thoroughly evaluated approach.
WHY LINEAR GENERATORS ARE USED
Electrical energy generation is being expanded by creative innovation, and linear generators are a large part of this trend.
The Wankel rotary engine named after the designer, Felix Wankel, was engineered in the early 1930’s. The rotary engine was unlike the conventional four stroke internal combustion engines and lacked the need for pistons, valves and camshafts. With only three moving parts involved in the design, this engine showed great promise in reliability and efficiency. The first Wankel rotary model was shown in 1960, not as an engine, but as a pump drive. Instead of the very complicated system involved in a conventional reciprocating piston engine, the wankel engine incorporated triangular “rotors” (see figure 1) that rotate within an epitrochoidal chamber around an eccentric shaft. Not only is this engine much more simple (only 3 moving parts rather
3. I. Boldea and S.A. Nasar, Linear Motion and Electromagnetic Systems. John Wiley & Sons Inc., 1995.
...ve a constant voltage because when you put a load on them, the voltage doesn’t change. There are two types of Van de Graaff generators but for now I will just focus on one. One that uses belts and rollers for charging and at the top there is a sphere where the electricity circulates.
The book, “A Raisin in the Sun,” was written by Lorraine Hansberry, and tells the story of an African American family living in impoverished, predominantly African American area of Chicago’s Southside, in the 1950s. The Youngers family had five members: Mama, Walter, Ruth, Beneatha, and Travis, and they all lived together in a crowded one bedroom apartment. The story is based on individual conversations with each family member and revolves around the question of what to do with ten thousand dollars insurance money, which was left as inheritance by Big Walter. Each character in the story has its own opinion on how to use the money, but all their thoughts depicted problems and issues which related to family, assimilation, racism, and American dream. Under Lorraine Hansberry’s writing, all four of main characters were somehow indicated as examples for each issue.
There is physics involved in these wind turbines as they change wind into mechanical energy and then into electricity. The energy produced depends on the volume of the air, the density, and the wind speed. The mass per unit time is the mass times the density times the wind speed or m = mass, p = density, A = area, and v = wind speed; m = pAV. Because the function of the wind turbine is to transform the wind’s kinetic energy into electricity the equation for kinetic energy is needed; KE = ½ mv2 or kinetic energy equals one half the mass times the velocity squared. Then, using substitution, the power in the wind depends on the density of the air, area swept out by rotors, and the cube of the velocity or ½ pAV3. Using Betz’ law the theoretical energy model for extracting 59% of the energy is power = 16/27(½ pAV3) .
We have all heard about the Titanic. Either we have watched the romance movie or done our research in a different way. No matter where we get our information from we know the biggest parts of the tragedy. The ship Titanic crashed into an iceberg on a cold April night on the Atlantic Ocean while sailing its first trip. But haven’t you ever wanted to know more details about? Maybe how the people who were on it and survived? How could the situation be prevented? Couldn’t they have saved more people? Well in the book “A Night to Remember” it has details on the Titanic you have probably never thought of knowing. While reading the first chapter some parts really caught my attention. One was when people felt the jolt from the collision with the ice berg people didn’t suspect what tragedy was to come. A girl named Marguerite Frolicher, who was accompanying her father on a business trip, woke up with a jump since she was half asleep she was thinking about ‘little white lake ferries’ landing sloppily which made her laugh and thought to herself “Isn’t it funny…we’re landing!”. They really did...
Problem to be Solved In the last year, PEP developed a type of low voltage motor that can reduce electricity cost and is safe for the environment. Recently, PEP has added more efficient low voltage motors
...e supernatural provides a catalyst for action by the characters. It supplies insight into the major players and it augments the impact of many key scenes. The supernatural appeals to the audience's curiosity of the mysterious and thus strengthens their interest.
The ship's captain was Edward Smith. The Titanic was built in Belfast, Northern Ireland on the spring of 1909, for transatlantic passenger and mail services, it was recorded that 15,000 workers helped in the building of the Titanic, on 14/04/1912 it departed from Southampton, England, heading to New York across the Atlantic Ocean but it went through freezing weather condition with many icebergs owing to human and mechanical errors, along it’s sail, the ship did not succeed in crossing the Atlantic Ocean and it cause many deaths and lot of pain for their families.
In the year of 1912 a historic ship named the Titanic set sail on a remarkable voyage. While the Titanic raised the bar on modern ship sailing during its time period, it also brought an abrupt scare to the industry after its untimely sinking. The titanic took a brief two years to build in an era lacking in modern robotics to help craft the a ship of such magnitude.[footnoteRef:1] While two years seem to be an eternity for most, in the terms of ship building to years is unusually quick. Unfortunately for the Titanic?s passengers this brought a grave ending for its majority. Many view the sinking of the Titanic in a seemingly tragic and negative light, it should rather be viewed as a tragic incident that in turn saved the lives of hundreds of thousands of people to come, simply from the lessons which were learned. While the Titanic's tragic sinking is not due to any one failure or complication, the Titanic's sinking in turn
Firstly, I would like to discuss the beginning of technology and how it has quickly changed. From 1822, the first rotating device that used electromagnetism that was built by Peter Barlow. To then, 12 years later in May 1834, the first actual working electric motor was built by Moritz Jacobi. 4 years later, in September 1838, Jacobi then improved the first electric motor, it was now powerful enough to drive a boat across a (wide) river, filled with 14 people. Although it wasn’t until 1839/1840 that other inventors, worldwide, were able to build motors that were of a higher performance. However, it wasn’t until 1868, that the first power station was built. The power station was used to power; lights, heating, inventions that produced hot water, an elevator, life saving devices and farm buildings. It wasn’t although until 1882, that the public power station started operation. Therefore technology advances, are our friend.
In a DC motor, the armature consists of any number of windings, each one an electromagnet. The armature is immersed in a directional external magnetic field. This external field does not move, and can come from permanent magnets or electromagnets.
electricity as the “fuel” instead of gasoline or some other combustible fuel. The electric motor in
Offshore wind turbines will provide more jobs, cut pollution, stop warming on our planet, and save us energy costs. These wind turbines can generate enough energy offshore to power about 500,000 homes. However, many people disagree with this idea because they believe it is too expensive. Offshore wind turbines have been a topic of discussion for a while now, and people just simply can’t agree. There are the supporters and there are the problem makers, as well as the advantages and disadvantages to this idea.
The wind is an incredibly valuable renewable energy source and is in the forefront of renewable energy developments. It is used to convert wind energy into energy that can be harnessed and used via a variety of methods, including; wind turbines, windmills, sails and windpumps. For a renewable energy source, however, it is wind turbines that are used to generate electricity (see figure 1). Wind power has been used for this since the end of the nineteenth century, after Professor James Blyth of the Royal College of Science and Technology first attempted it (Boyle, 2012). However, It wasn’t until the 1980s that using wind power technology was sufficient enough to experience a rapid growth of the technology.