The squirrel cage induction generator for power generation
电机电器及其控制技术-英文资料
2.1 Effects and Development of Machine
What is Electrical Machine? ----------An Electrical machine is a device that converts mechanical energy to electrical energy or vice versa, and changes AC voltage from one level to another level according to law of electromagnetic induction.
The British Hopkinson also invented a transformer with closed magnetic circuit.
Bullough invented high voltage oil immersion transformer, which makes long-distance high-voltage transmission a reality.
2.1 Effects and Development of Machine
Effects of Machine
Power production, transmission and distribution Generator Transformer
……
Drive machinery and
equipment Motor
1888
Faraday invented the model of the first induction generator.
Jacobi invented rod core motor which power is 15W.
蝴蝶的生命周期 英语作文
The Life Cycle of a ButterflyThe life cycle of a butterfly is a fascinating and intricate process that showcases the wonders of nature and the incredible transformations that occur in the insect world.This process,known as metamorphosis, involves four distinct stages:egg,larva(caterpillar),pupa(chrysalis),and adult butterfly.Each stage is crucial for the development and survival of the butterfly,and together they form a remarkable journey from a tiny egg to a beautiful,winged insect.The first stage of a butterfly's life cycle begins with the egg.Female butterflies lay their eggs on the leaves of specific host plants,which will later serve as food for the emerging caterpillars.The eggs are often tiny and can vary in shape and color depending on the species.The duration of the egg stage can range from a few days to several weeks,depending on environmental conditions such as temperature and humidity.Once the egg hatches,the second stage of the life cycle begins:the larva, commonly known as a caterpillar.Caterpillars are voracious eaters and spend most of their time consuming the leaves of their host plants.This stage is characterized by rapid growth,and as the caterpillar grows,it undergoes a series of molts,shedding its exoskeleton to accommodate its increasing size.Caterpillars can have a wide variety of colors,patterns, and shapes,which often serve as camouflage or a warning to predators. The larval stage is critical for accumulating the energy and nutrients needed for the next stage of development.After reaching a certain size and undergoing several molts,the caterpillar enters the third stage of the life cycle:the pupa,or chrysalis. During this stage,the caterpillar undergoes a remarkable transformation. It finds a suitable spot to attach itself,often using silk,and then sheds its final larval skin to reveal the chrysalis.Inside the chrysalis,the caterpillar's body undergoes a complete reorganization through a process called histolysis,where larval tissues break down,and histogenesis,where adult structures form.This transformation can take anywhere from a few weeks to several months,depending on the species and environmental factors.The final stage of the butterfly's life cycle is the adult butterfly.When the transformation within the chrysalis is complete,the adult butterflyemerges.This process,known as eclosion,involves the butterfly breaking free from the chrysalis and expanding its wings.Initially,the wings are soft and crumpled,but within a few hours,they harden and become strong enough for flight.The adult butterfly's primary focus is on reproduction and feeding.Butterflies are known for their striking colors and patterns,which serve various purposes,including attracting mates,camouflage,and warning predators.Adult butterflies feed on nectar from flowers,using their long proboscis to reach deep into the blossoms.They play a vital role in pollination, transferring pollen from one flower to another as they feed.This mutualistic relationship benefits both the butterflies and the plants, contributing to the health and diversity of ecosystems.In conclusion,the life cycle of a butterfly is a remarkable journey that highlights the beauty and complexity of nature.From the tiny egg to the vibrant adult butterfly,each stage of metamorphosis is a testament to the adaptability and resilience of these incredible insects.Understanding and appreciating the life cycle of butterflies not only deepens our connection to the natural world but also underscores the importance of conserving their habitats and ensuring the survival of these delicate and enchanting creatures for future generations to enjoy.。
植物与环境保护作文英语
Plants play a vital role in environmental protection,and their importance cannot be overstated.Here are some key points to consider when discussing the relationship between plants and environmental conservation:1.Air Purification:Plants are natural air purifiers.They absorb carbon dioxide and release oxygen through the process of photosynthesis.This helps to maintain the balance of gases in the atmosphere,which is essential for the survival of all living organisms.2.Climate Regulation:Large forests act as carbon sinks,absorbing more carbon dioxide than they release.This helps to mitigate the effects of climate change by reducing the amount of greenhouse gases in the atmosphere.3.Soil Conservation:The roots of plants help to hold the soil together,preventing erosion. This is particularly important in areas prone to landslides or where soil is easily washed away by rain.4.Water Filtration:Plants can filter pollutants from water,improving the quality of water in streams,rivers,and lakes.This is especially important in areas where industrial or agricultural runoff can contaminate water sources.5.Biodiversity:Plant diversity is crucial for maintaining a healthy ecosystem.Different types of plants provide habitats and food for a wide range of animals,contributing to the overall biodiversity of an area.6.Noise Reduction:Urban green spaces,such as parks and gardens,can help to reduce noise pollution in cities.The leaves and branches of plants absorb and deflect sound waves,creating a quieter environment.7.Recreation and Mental Health:Plants and green spaces offer recreational benefits, providing areas for people to relax and enjoy nature.Studies have shown that spending time in green spaces can improve mental health and wellbeing.8.Economic Benefits:Plantbased industries,such as agriculture and forestry,contribute significantly to the economy.Moreover,plants can be used for medicinal purposes, providing natural remedies for various ailments.9.Cultural and Aesthetic Value:Plants are often associated with cultural practices and aesthetics.They can be used for decoration,in religious ceremonies,and are a source of inspiration for art and literature.cational Value:Plants are an excellent tool for teaching about biology,ecology, and environmental science.They can be used to demonstrate concepts such as growth, reproduction,and the interdependence of living organisms.In conclusion,plants are integral to the health of our planet and the wellbeing of its inhabitants.It is our responsibility to protect and preserve plant life for the benefit of future generations.This can be achieved through sustainable practices,such as planting trees,conserving water,and reducing the use of harmful chemicals that can damage plant life.。
太阳对鱼类的影响英语作文
The sun plays a crucial role in the life of fish, affecting their behavior, growth, and overall health. Heres a detailed look at the various ways the sun impacts fish:1. Light Cycle and Circadian Rhythms: Fish, like many other creatures, have internal clocks that regulate their daily activities. The suns light cycle helps set these circadian rhythms, influencing when fish feed, rest, and reproduce.2. Photosynthesis and Food Chain: The sun is the primary energy source for aquatic ecosystems. Through photosynthesis, it powers the growth of phytoplankton, which forms the base of the aquatic food chain. Fish consume these organisms directly or indirectly, which is essential for their survival and growth.3. Thermoregulation: The suns heat helps regulate the temperature of water bodies. Fish are ectothermic, meaning they rely on external sources to regulate their body temperature. Warmer water can increase their metabolism and growth rates, while colder water can slow them down.4. Migration Patterns: Many fish species migrate to spawn or feed, and the suns position in the sky can serve as a natural compass. For example, salmon use the sun to navigate their way back to their natal streams to spawn.5. Behavioral Changes: The sun can influence the behavior of fish in various ways. For instance, some fish are more active during the day diurnal, while others are nocturnal. The suns position affects their feeding and mating behaviors.6. Vision and Coloration: Fish rely on sunlight to see their surroundings. The intensity and quality of light can affect their vision, which in turn influences their ability to find food and avoid predators. Additionally, the suns rays can influence the coloration of fish, which is important for camouflage and communication.7. Reproduction: The suns light can stimulate the production of certain hormones in fish that are linked to reproduction. Seasonal changes in daylight hours can trigger spawning behaviors in many species.8. UV Radiation: While sunlight is essential for many aspects of a fishs life, ultraviolet UV radiation can also have negative effects. Prolonged exposure to UV light can damage fish skin and eyes, and it can also lead to an increase in the production of harmful substances in the water.9. Water Clarity and Habitat: The suns penetration into water affects its clarity, which inturn influences the habitat of fish. Clear water allows more light to penetrate, supportinga more diverse and abundant ecosystem.10. Seasonal Adaptations: Fish have adapted to the changing seasons and the corresponding changes in sunlight. For example, some fish species may grow thicker skins or change their feeding habits in response to shorter daylight hours during winter. In conclusion, the sun is a fundamental factor in the life of fish, affecting their biology, behavior, and interactions with their environment. Understanding these impacts is essential for the conservation of aquatic ecosystems and the species that inhabit them.。
鸟巢英语作文五年级
The Birds Nest,also known as the Beijing National Stadium,is an iconic structure in Beijing,China.It is a magnificent piece of architecture that has become a symbol of modern Beijing.Heres a detailed description that you can use for a fifthgrade English composition about the Birds Nest.Title:The Birds Nest A Modern MarvelIntroduction:The Birds Nest is not just a stadium its a testament to human ingenuity and creativity.It is a place where dreams take flight and where athletes from all over the world come to compete and showcase their talents.This essay will explore the architectural marvel that is the Birds Nest,its significance in Beijing,and its impact on the world of sports. Design and Construction:The Birds Nest was designed by the Swiss architecture firm Herzog de Meuron in collaboration with ArupSport and China Architecture Design Research Group.The design is a unique blend of traditional Chinese elements and modern architecture.The structure is made of a series of interlocking steel beams,which give it the appearance of a birds nest.The construction of the Birds Nest began in2003and was completed in2008, just in time for the Beijing Olympics.Architectural Features:One of the most striking features of the Birds Nest is its exterior.The steel beams are arranged in a lattice pattern,creating a visually stunning effect.The stadium can seat up to91,000spectators,making it one of the largest in the world.The roof of the stadium is partially open,allowing natural light to filter in and providing a unique viewing experience for spectators.Significance in Beijing:The Birds Nest is a symbol of Beijings rapid development and its emergence as a global city.It is a place where history meets modernity,and tradition is fused with innovation. The stadium is located in the Olympic Green,a large park that was built as part of Beijings Olympic legacy.The park is a popular destination for locals and tourists alike, offering a variety of recreational activities and cultural experiences.Impact on Sports:The Birds Nest has played a significant role in the world of sports.It was the main venue for the2008Summer Olympics,hosting the opening and closing ceremonies,as well asthe track and field events.Since then,it has continued to host major sporting events, including the2015World Athletics Championships.The Birds Nest has also become a symbol of sportsmanship and international cooperation,as athletes from different countries come together to compete and celebrate their achievements. Conclusion:The Birds Nest is more than just a stadium it is a symbol of Beijings progress and a testament to the power of human creativity.It is a place where dreams are made and where the spirit of competition is celebrated.As we look to the future,the Birds Nest will continue to inspire and captivate,serving as a reminder of the limitless potential of human achievement.This composition provides a comprehensive overview of the Birds Nest,suitable for a fifthgrade students understanding and writing ability.It covers the essential aspects of the stadium,from its design and construction to its cultural and historical significance.。
关于松鼠的英语作文
The Life of SquirrelsSquirrels are intriguing and lively creatures that belong to the family Sciuridae.They are commonly found in both urban and rural areas, known for their bushy tails and swift movements.These small rodents captivate our attention with their playful behavior and remarkable adaptability.One of the most notable characteristics of squirrels is their agility.With their strong hind legs and sharp claws,they can effortlessly climb trees and leap from branch to branch.This dexterity not only helps them escape predators but also aids in foraging for food.Squirrels are known to store nuts and seeds in various hiding spots,a behavior called caching, which ensures they have a food supply during the harsh winter months.Squirrels have a diverse diet that mainly includes nuts,seeds,fruits,and occasionally insects.Acorns are particularly favored,and squirrels play a crucial role in forest regeneration by burying these seeds.Some of these seeds are forgotten,which then sprout into new trees,demonstrating the essential ecological role that squirrels play.The intelligence of squirrels is another fascinating aspect.They are quick learners and can solve complex puzzles,especially when it comes to accessing food.Many homeowners have witnessed the clever tactics squirrels use to raid bird feeders,showcasing their problem-solving skills. Squirrels also communicate using a variety of vocalizations and tail movements.They produce distinct sounds to signal danger,attract mates,or establish territory.Their bushy tails are not just for balance but also serve as a communication tool,helping them convey messages to other squirrels.The habitat of squirrels varies widely.While some prefer the dense canopy of forests,others have adapted to urban environments,finding homes in parks and backyards.Their ability to thrive in different settings is a testament to their resilience and adaptability.In conclusion,squirrels are more than just cute,furry animals.They are intelligent,agile,and play a significant role in their ecosystems.Observing them can be both entertaining and educational,offering insights into the behaviors and adaptations of wildlife.。
为丑的动物发声英语作文
为丑的动物发声英语作文英文回答：Ugly animals play an important role in our ecosystem, despite their unattractive appearance. Take the naked mole rat, for example. This creature may not be the most visually appealing, with its wrinkled, hairless skin and large front teeth. However, it has some fascinating qualities that make it an essential part of its habitat. Naked mole rats are highly social animals, living in underground colonies. They have a unique ability to tolerate high levels of carbon dioxide, which allows them to survive in the low-oxygen environment of their burrows. Additionally, they are resistant to cancer, making them valuable subjects for medical research. So, even though naked mole rats may not win any beauty contests, they are crucial for maintaining the balance in their ecosystem.Another example of an ugly animal that deserves our attention is the blobfish. This fish has a gelatinous,blob-like appearance that has earned it the title of"world's ugliest animal." However, its unusual appearanceis actually an adaptation to its deep-sea habitat. The blobfish lives at depths where the pressure is severaltimes higher than at the surface. Its gelatinous body helps it maintain buoyancy in these extreme conditions. While the blobfish may not be conventionally attractive, it serves a vital role in its ecosystem by scavenging on the oceanfloor and contributing to the food chain.中文回答：丑陋的动物在我们的生态系统中扮演着重要的角色，尽管它们外表不太吸引人。
老鹰抓小鸡亲子英语作文
老鹰抓小鸡亲子英语作文Title: The Eagle and the Chick: An Adventure inLearning English Together。
Once upon a time, high up in the towering trees of the forest, there lived a majestic eagle and her curious chick. They shared a bond of love and learning, and their dayswere filled with exciting adventures and valuable lessons. One day, as they soared through the clear blue sky, the chick turned to her mother with a question burning in her heart."Mom," the chick chirped, "why do we speak English?"The eagle smiled, her feathers gleaming in the sunlight. "English is a language spoken by many creatures across the world," she explained. "It opens doors to communication, knowledge, and understanding."Excited by this newfound knowledge, the chick flutteredher wings in anticipation. "Will you teach me English, Mom?" she asked eagerly.And so, their journey of learning began. Every day, the eagle and her chick would explore the vast forest, encountering different animals and objects along the way. With each encounter, the eagle would teach her chick new words and phrases, patiently guiding her through the intricacies of the English language.One sunny morning, as they perched on a sturdy branch overlooking a lush meadow, they spotted a group of rabbits hopping about in the grass. The chick's eyes sparkled with curiosity as she observed the playful creatures."What are those fluffy creatures called, Mom?" she inquired."They are called rabbits," the eagle replied. "And when they move quickly, we say they are hopping."The chick nodded, committing the new words to memory."Rabbits hop," she repeated, testing out the phrase with delight.As they continued their journey, the eagle and herchick encountered many more animals, each providing an opportunity for the chick to expand her English vocabulary. From squirrels scurrying up trees to butterflies fluttering among the flowers, the forest was alive with learning possibilities.But it wasn't just the animals that taught the chick English. She also learned from the natural wonders of the forest itself. The eagle would point out towering trees, babbling brooks, and shimmering sunlight, teaching herchick the names of the world around them.As the days turned into weeks and the weeks into months, the chick's English skills grew stronger with each passing day. She began to string together sentences, expressing her thoughts and feelings with newfound confidence.One evening, as they watched the sunset paint the skyin hues of orange and pink, the chick turned to her mother with a smile."Thank you, Mom," she chirped. "For teaching me English and showing me the beauty of the world."The eagle wrapped her wing around her chick, her heart swelling with pride. "You are my greatest joy," she said. "And together, we will continue to soar and learn, side by side."And so, the eagle and her chick embarked on many more adventures, their bond growing stronger with each passing day. For in the forest of life, there is no greater treasure than the love between a parent and child, and the joy of learning together.。
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MOTOR I N ACTION I
The Squirrel-Cage Induction Generator for Power Generation
T. C
TSAO
N. F.
MEM
M E MB-ER
TSANG
Á1źÅ
Y N C H R O N O U S altersynchronous turboalternaBecause of its simplicity, the squirrel-cage inductors.1 However, new probnators now are being tion generator deserves revaluation in the field lems in design may arise with used almost exclusively of power supply. Under appropriate conditions, its low cost and maintenance makes it high-speed high-power inducas main generating units in an economical means of supporting synchronous tion generators. Tooth pulsacentral power stations. The alternators. tion loss plays an important reason is obvious: they generole. Totally enclosed rotor rate both kilowatts and reacslots, magnetic wedges for tive kilovolt-amperes to suit the load conditions and they produce a standard frequency stator slots, and relatively large air gap may be resorted for synchronization and interconnection. Induction gener- to. In fact, for a 2-pole large machine leakage reactance ators usually are installed in relatively small sizes; for is generally low, and, as the short-circuit current is limited although they supply active power, they take reactive by leakage reactance, it is usually necessary to provide current from other synchronous machines. In other extra leakage paths for limiting the transient current. words, irrespective of load conditions, the induction genIf an induction generator is brought up to speed and erator must operate at leading power factor. However, switched to a power line, a large transient current will the induction generator has certain economic advantages flow. This will cause disturbance on the line. One in simplified rotor design which is well adapted for high method to obviate this inrush would be to connect shunt speed operation. It requires no exciter, voltage regu- capacitors corresponding to a somewhat higher susceptance lator, or synchronizing and frequency control equipment. than that of the unsaturated generator. This machine is Induction generators and induction motors have many brought up to synchronous speed and then switched to the points in common. If an induction motor is driven by line in series with a resistance of 3 to 5 per unit, based upon outside mechanical source at speeds above synchronism, the generator rating. In case the generator has not built the power current component in the stator reverses while up its voltage before switching, it will build up in a short the magnetizing component remains in magnitude and in time and then the resistance may be short-circuited. With phase position, as shown in Figure 1. The machine thus this arrangement the disturbance is minimized and the is converted to a generator, and will deliver active power equipment costs very little, since it has only to absorb the when its shaft input has overcome its internal losses. heat produced by the relatively small transient current for It is evident that current of practically equal magnitudes a very short time. This amount of shunt capacitors may will flow through the stator in the case of generator as in be left permanently connected to the generator. Additional capacitors can be provided as needed. the case of motor at a given slip, which is defined as slip = rotor copper loss power transferred across air gap
Essential text of papel 51-158 ^Squirrel-Cage Induction Generator for Power Generation," recommended by-tite AIEE Committee on Rotating Machinery and approved by the AIEE Technical Program Committee for presentation at the A I E E Great Lakes District Meeting, Madison, Wis., May 17-19, 1951. Not scheduled for publication in AIEE Transactions. T. C Ttao is with the Consolidated Edison Company of New York, Inc., New York, N. Y., and N. F. Tsang is with die University of Minnesota, Minneapolis, M i n n . The authors wish to acknowledge their indebtedness to J . G. Noest and M . J . Steinberg for their inspiration; to Professors R. Rudcnberg, N . M. Liwschitz, C. L. Dawes, E. W. Boehne, and K. L. Wildes for comments; and to P. L. Alger, T . M . Linville, A. H Gruehr, W. T . Grumbly, G. L. Sullivan, Y. H . Ku, L. A. Nettleton, and S. T . Meurer for their advice and assistance.