Risk Management and asset allocation Research Proposal

Risk Management and asset allocation - Research Proposal Example According to The New York Times (2011), â€Å"Asset allocation† describes dividing one's investments among the various types of asset classes. This is like saying putting one’s eggs in different baskets. Pietersz (2005) observes that asset allocation â€Å"helps ensure that investments are spread out across a wide range of markets and securities.† They do so because asset allocation does not have a one-off surety for success – it may either succeed or backfire, depending on who is handling the asset. Grange (2010) relates exposure management to the nature of product being invested in. He recognizes two major products, which are those â€Å"made up of those products that start with a balance equal to their limit and where, over time, the balance decreases away from the limit† and those which â€Å"start with a zero balance and some higher limit and where, over time, the balance increases towards the limit†. Generally, in the first instance, ex posure created is classified as productive whereas in the second instance, all exposure created is classified as unproductive. ... some who believe that much of a success in asset allocation should be looked at in terms of who handles which venture rather than the type of equity or portfolio it is. Such an argument gives operators of private equity some hope of competition in asset allocation. 1.2 Hypothesis The type of equity; be is private or public does not have significant influence on the rate of success in asset allocation. Private equity can perform as creditably well as a public equity. Public equity is not a guaranteed choice for asset allocation. Success in asset allocation is influenced by several managerial factors including exposure management. 1.3 Research Questions 1. Which factors inform the choice of a particular venture for asset allocation? 2. Why has private equity investment become so popular? 3. What is the most favorable private equity share in a general asset allocation? 4. To what extent does private equity expose investors? 5. How can a private equity exposure be derived? 6. What are th e risks in overrunning a specific allocation and how can it be reduced? 7. Which model can be used to appraise the future of asset allocated in private equity? 1.4 Objectives 1.4.1 Main Objective To find the relationship between private equity, their exposure management practice and the degree of success in investing in private equity as an option for asset allocation 1.4.2 Specific Objectives 1. Identify the basis upon which private equities operate. 2. Explore the exposure management practices of private equities. 3. Find out from investors, why they choose and prefer private equities for asset allocation. 4. Find authentication or otherwise to claims that asset allocation in private equity is risky due to poor exposure management. 5. Prescribe models that can best be used to appraise

In relation to E -Business Maturity and E- Modles select three Assignment

In relation to E -Business Maturity and E- Modles select three organisation - Assignment Example Different online firms exhibit different levels of E-Business maturity depending on the standards of their applications and services (Fox, 2001, p.231). A clear comprehension of E-Business models can be employed appropriately to maximize future benefits. The objective of this paper is to discuss levels of E-business maturity in relation to three different organisations. E-Business Maturity As various enterprises go through different phases of e-business maturity, they encounter same challenges while incorporating this technology in their business operations. They need to validate with their competitors and equals to be able to match forward in the right direction (Bak & Stair, 2011, p. 186). Due to the fact that all businesses experience similar predicaments in this endeavor, their development steps can be portrayed as phases of maturity. The fundamental concept of study here is that all these businesses go through same phases of maturity with regards to the approaches they utilize a nd how they manage to sustain and drive business objective and processes (Garrett, 2006, p.10). The E-Business maturity model provides a platform under which one can establish where a business is positioned and pin-points high-priority advancement areas that ought to be addressed to enhance current maturity phase. The model elucidates the steps that ought to be taken to move a notch higher to an upper stage (Gosselin, 2009, p.86). The primary fact here is that improved E-Business maturity is directly connected to better outcomes with regards to a business’s capacity to inevitably implement E-Business programmes and processes. Improved maturity is likely to translate to maximised financial benefits from investments (Gangopadhyay, 2002, p.202). A noteworthy point is that this model describes the approaches and levels of E-Business strategy development. However, it is not designed to offer insights in the soundness of the chosen strategy. This kind of information can only be acq uired by examining external factors, such as the environment, and organisational ones such as goods and services, clients and relevant authorities (Weill & Vitale, 2001, p.11). The five levels of the E-Consciousness Rising Model developed by the Price Waterhouse provide an elaborate platform under which maturity levels of different E- Businesses can be assessed. Masala Wok is a multinational food chain store that has several branches in different parts of the world. The food chain store serves Indo-Chinese cuisine. Going by the E-Consciousness Rising Maturity Model designed by the Price Waterhouse, the company’s electronic business website falls at the first stage. This is the Online Presence phase that groups organisations that have implemented static information to their online systems. There is minimal interaction other than information about the company, delicacies and services offered, and picture gallery. The website is designed to market the services offered by Masala Wok and provide directions on how to access their restaurants. The company does not engage in online retail and home delivery services. For this reason, the website system is quite basic and has no complex components interconnecting clients to suppliers and brokers. Ablecan is a visa agency firm that is well situated at the heart of London. The company’s area of specialty is acquiring business and tourist visa on behalf of United Kingdom residents willing to

Porter's five forces Case Study Example | Topics and Well Written Essays - 500 words

Porter's five forces - Case Study Example Start up of soft drink industry requires high financial capital, labor, marketing, warehousing and advertising. The situation makes it difficult for a competitor to enter into the industry and expand. Additionally, Coca Cola Company has made huge investments in their advertisements which resulted to brand loyalty with its customers throughout the world. For example, Coca Cola Company’s advertising strategy made it attain a larger market share in 2011 than its rival Pepsi. The market of Coca Cola was at 41.9%, the market share for its rival Pepsi was at 29.9%. The advantage was driven by huge investment Coca Cola Company makes in advertising (Russell). The main substitutes of Coca Cola products are bottled water, tea, coffee and sport drinks. Consumers are currently more concern about their health. They have begun cutting down on the demand of sodas because of the view that they contribute highly to obesity due to its high caloric content. Additionally, tea and coffee are a threat to Coca Cola products because they have caffeine and customers can decide to buy it. This makes the substitute products stronger and a threat to the Coca Cola Company (Russell). Raw materials essential for manufacturing Coca Cola products are basic raw materials such as sugar, flavor, color and packaging materials. The suppliers of the above materials have low bargaining power because materials are easy to obtain and there are many suppliers in the market. However, with recent inflation of the price of goods, cost of materials such as sugar and packaging increased. This affects the profits of Coca Cola Company (Hill and Jones 44). The Coca Cola Company and any other company distribute their soft drinks to convenience stores, restaurants, supermarkets and large grocers for resale directly to customers. They are the buyers of Coca Cola products, and they buy the products in large quantities for

What are the main sources of international competitive advantage Think Essay

What are the main sources of international competitive advantage Think about a successful product in your country, what are the - Essay Example Focus Strategy: When a business implements any of the cost leadership or differentiation strategy but in a specific customer target group like in a specific geographical area, the niche segment or a specialized line of products. Competitive advantage is achieved by making optimal use of the resources and the capabilities of then business to create a structure with lower cost or a differentiated product. Achieving a sustainable competitive advantage makes a firm capable of creating more value for its customers and deriving super profits from the business. The main sources of competitive advantage are the asset resources, capabilities and the key success factors. In this report we consider the Porsche cars to study the process of competitive advantage achieved by this line of products. Discussion Porsche is a highly profitable company which manufactures luxurious premium cars. The brand offer elegance and comfort in their products and is segmented as a premium product. Porsche cars hav e gained enormous competitive advantage by implementing a focus differentiation strategy. ... To ensure serving these customers effectively and ensure brand loyalty, Porsche has developed unique aligned capabilities. The mission statement of Porsche is perfectly aligned with their strategic planning thus creating an authentic and unique product. The brand has achieved ultimate competitive advantage by strategically combining quality and uniqueness in its products. The lean production system adopted in the manufacturing of the cars is a key factor in gaining competitive advantage for the product. The resources maintained by the company is carefully chosen and highly maintained. The human resources and the physical resources of the brand add to the value chain. Porsche recruits highly qualified people as their staff and extensively train them to make them competent enough. The employees are imparted with necessary skills through training centres all over the world and in Germany especially. The company supports and motivates their staff by maintaining a financial incentive stru cture where a percentage of the yearly turnover is given as incentives to the employees of Porsche according to the company results. The physical resources of the company are of high quality and the manufacturing process involves using materials of high quality and the use of advanced technology (Porter, 2008, p. 68). The Research and Development team of Porsche in Germany tries to innovate and create superior quality and unique products so as to achieve sustainable competitive advantage. The configuration of the manufacturing plants is concentrated and every department of production is maintained in the closest possible place. Only few parts are imported from other countries or taken from other

Consider Two Contrasting Characters In The Play Essay Example for Free

Consider Two Contrasting Characters In The Play Essay Consider two contrasting characters in the play. How does the playwright convey their personalities and their attitudes to the situation in which they find themselves? The playwright of The Long, the Short and the Tall is Willis Hall and he wrote it in 1959. The play is set in the Malaysian jungle in 1942 during the Second World War. It is about a British scout patrol, which is caught in the unexpected Japanese advance down the Malaysian peninsula. It deals with men from all over Britain, from different backgrounds and cultures, and their relationships with each other. The main issue though, is whether the men are able to kill another human being. It shows their reactions in tense and almost unreal situations. World War Two lasted from 1939 to 1945. It was fought in two places; in Europe against Germany and in the Pacific against Japan. Britain and the USA started fighting against Japan because Japan bombed Pearl Harbour in December 1941, which had docked a whole fleet of American war ships. The British and the Americans didnt expect the Japanese to attack, so they were not able to defend themselves. From here Japan continued to expand into other countries. They quickly conquered South-East Asia. The next thing the Japanese did was to invade Singapore in Malaysia. Again the British were completely unprepared for the attack. All Singapores defences were facing into the sea, never expecting or believing that anybody would come down the peninsula, through the jungle, but this is exactly what the Japanese did. Because no one in Singapore believed that they would be attacked from the land side, all the defences were on the ocean side, to protect against a marine attack. The Japanese were so successful because they had had better training in jungle warfare. They wore light clothing, had light ammunition and made use of bicycles for transport. This meant that they could travel great distances in a relatively short time. There wasnt much hope for the British soldiers, who had little or no training in jungle warfare, they had heavy clothing and ammunition and no suitable transport. Morale in the British army was very low. Most of the soldiers were conscripts who were very cynical about the ability of the generals of the army to direct the army in the right away and also because of the lack of proper training and equipment. This can be seen in the play in the way the characters talk of the radio not working. Damn duff equipment is how Johnstone describes the radio. To the British conscripts the Japanese army seemed invincible, with their incredibly patriotic soldiers who were prepared to die rather than surrender. The Japanese believed in the motto Death before dishonour. They seemed a completely fearless army because of this, which didnt do the morale of the British soldiers much good. The two contrasting characters I have chosen to look at are Bamforth and Johnstone. I have chosen Bamforth because his character changes a great deal throughout the play and his point of view moves to a different angle and I have chosen Johnstone because his character is one of the few ones, which doesnt change much throughout the play. Private C. Bamforth is a conscript into the British army and has been posted over to the Far East to help fight the Japanese. He is from London and is in the lowest possible rank in the army. His position is completely different from Johnstones. His full title is Corporal E. Johnstone. He is two above Bamforth in ranks and is part of the regular army and is not conscripted. This means that is attitude to the army is different. His attitude is much less cynical and he respects authority more, in terms of Mitchem. He is cynical in one part of the play where he becomes exasperated when the radio wont work. Damn duff equipment. The whole damn issues duff. But overall he is much less cynical of the British armys capabilities. On the other side Bamforth is very cynical of the British army in the way he speaks of it. He apparently quotes one of the Generals, Bammo, my old son, the British armys in a desperate situation. The yellow perils about to descend on us Here he is joking about the state of the British army, but he obviously believes it, otherwise he wouldnt be saying it and it wouldnt be funny. Also he makes clear that he isnt prepared to be a hero, I wasnt meant to be a hero he states it clearly and decisively, which shows that he has no doubts about it. Bamforth enjoys making fun of others especially people who cant defend themselves very well like Whitaker and people who are of a certain area such as Wales or Scotland. He tends to generalise about people of a certain area and call them derogatory names. You Scotch haggis!, you Cardiff creep, Youre an ignorant Welsh Taff! He is a really unpleasant character in the beginning and obviously resents authrority; Nit is what he says under his breath at Johnstone. Johnstone is also unpleasant in the way he threatens Bamforth, but as the person watching the play, with no knowledge of how Bamforths character will change, I found that I sympathised with Johnstone and felt glad that he was giving Bamforth what he deserved. Their initial reaction was also very similar, as it was Johnstone who grabbed the prisoner and ordered one of the other men to kill him with their bayonet and Bamforth was the only other soldier who felt able to kill him. He regarded the Japanese soldier as only as important as an animal. Its only the same as carving up a pig. The prisoner was very low in his opinion Johnstone has very little contact with the prisoner; he only has direct contact with the prisoner when he has the argument with Bamforth over whether the prisoner should be allowed any cigarettes. He obviously has strong opinions on what should happen to the prisoner; he thinks it is a bad decision of Mitchems to take the prisoner back as it is too risky. He tries to argue with Mitchem that they should kill the prisoner right then, before it all got out of hand. Get rid of him. Right now Strangely enough, it is Bamforth who befriends the prisoner and talks to him and joke with him. He even begins to regard the prisoner as almost human. Hes almost human this one is!. His opinion of the prisoner has risen from that of animal to almost human. This is because the prisoner showed him his photos of his family. He indicates that he also has a baby, this is probably why Bamforth begins to regard him with more respect. Next Bamforth offers the prisoner a cigarette, but Johnstone knocks the prisoners from his mouth. At once Bamforth demands an explanation from Johnstone. Here he is clearly defending the prisoners rights, but also I think that he argues with Johnstone just because he did something that infringed his rights. Later on when the argument about the prisoners cigarette case begins, the playwright cleverly makes Bamforth leave so that the argument can progress without anyone coming to the prisoners defence. When Bamforth returns the argument reaches a climax; he immediately comes to the prisoners defence. He defends him verbally and helps the prisoner. He tells the others that he gave the prisoner the cigarettes. This may not have been true and I dont think that Johnstone really believed him. He is the one who asks to look at the case before it is returned to the prisoner and he starts another argument about the case. This time Bamforth does not claim to have given it to him, but turns the story back on Johnstone by making Whitaker tell the others how he has a locker full of Japanese souvenirs. He defends the prisoner all the way. This is sign that he has become really attached to the prisoner. By the end when they have to decide whether to kill the prisoner or not, Bamforth has become very attached to the prisoner. He physically stands in-between the prisoner and Johnstone, as can be seen from the stage directions. This is a clear piece of proof that he is now prepared physically protect the prisoner not just argue for him. Its him and me. This shows that he is saying that if they want to kill the prisoner, they will have to kill him too. Also he now expresses freely that he regard the prisoner highly. Hes a man, showing that the prisoner has earned a lot of Bamforths respect. Johnstone on the other hand is the one who is trying to kill the prisoner. Johnstone still thinks they should kill the prisoner and his opinion of him has not risen either, Its a bloody nip From this we can see that he regards him as really low because he says it instead of he and uses the derogatory term of bloody nip. He orders Bamforth out of the way, but he will not move and appeals to each of the men in turn to help him. But each one turns him down, he appeals to Macleish last of all, probably hoping that at least he was going to help him because his brother could be a POW too. But even he does not help Bamforth. He is obviously desperate because he turns to sheer pettiness when each of the men turn him down. I hope they carve your brother up. Get that? I hope they carve your bloody brother up! In the end the decision is made for them as Whitaker shoots the prisoner as he rises, during the fight between Bamforth and Johnstone. The play offers no obvious answers to who was right or what they should have done. It was quite ironic how it is Johnstone left alive at the end who surrenders because it is was he who was prepared to kill their POW, having said this he did not have much choice in the matter. Personally I really dont know what they should have done because it was such a hard decision, but if I had to make a decision I would probably have tried to take the prisoner back to camp rather than hanging around arguing about it. If they had done that they might have had a chance of getting back alive, but as it was they had no hope. With the benefit of hindsight, I can see that Johnstone was right, when he said that they should kill the prisoner in the beginning, when none of them were attached to the prisoner and there would have been no problem. However I dont think I would be able to kill someone in that situation even if I was ordered to.

Indian or Singaporean English Essay Example for Free

Indian or Singaporean English Essay Indeed, language has been one of the most fundamental elements of culture. As such, culture and history brings about a language. However, in today’s society, English is slowly becoming a global language. This is to say, many people are learning English as their second language and because of this, dialects are starting to form out of English. These smaller versions of English bring to it the culture of those trying to learn it – whether they are African-Americans, Hispanics or Asians. Because each is unique and is a reflection of different cultures, the label of Standard English used by Americans is a bit inappropriate. To say that there is one standard means that the others are less formal or different from the norm. In fact, it is not the deviation from the standard that sets these apart but culture and history, which is brought about by these dialects. For me, Hispanics speaking English brings into the language the passion and intensity of the Spanish language. It should not be looked down upon as is the case of Ebonics or Black English. Some words that are not normally used by pure white Americans may be included in such dialects but it is not because it is slang or informal, but because it is a reflection of the heritage that speaks them – whether it be African Americans or Hispanics. People should be proud of how they speak even though it may not be classified as â€Å"standard† because the way they speak shows who they are. In learning English, it is not good to simply copy how the majority speaks English but to learn the language but still let our native culture and heritage to shine through. This is why I feel that it is very appalling when people think a dialect is uncultured or uneducated when in fact it is simple a different kind of culture and education that is being shown by the dialect. In fact, the assumption of a â€Å"standard† only means that the people who define which are the norms are the ones in power. They use â€Å"standard† English and therefore, they want their type of language to be the best. They themselves are proud of their way of speaking and want everybody to understand the beauty of their type of English. However, this is also the case for everyone. Now, if only minorities would see their dialects in the same way then they too can consider their dialect as, not only valid, but also equally respectable and normal. Growing up and learning English as my second language has helped me gain a respect for my Hispanic-Anglish language. It shows that even if I speak a different language than my native tongue, I am still able to hold on to who I am and still my culture and history is brought out whenever I speak. This certain kind of pride helps me to feel respected and part of the norm. However, I know that society is a tough crowd. Even though I may feel my brand of English is beautiful and at equal footing with the â€Å"standard†, officially, I know that there is a certain type of success associated with some variations of English. The language as spoken by Americans or English will still be considered as better and more educated by most people. That is why I am hoping my daughter will be given the same benefits as local Americans or naturally English speaking people because her first language and my husband’s first language is English. I do not feel there is something else I can do to change this fact, since I know it is integrated already into the mindset and system of society. It is institutionally and culturally accepted. However, for me who is learning English, I do not feel compelled to make other people speak â€Å"standard† English in order to treat them better or to look upon them with more respect and/or admiration. I know for a fact that most people learning another language puts in the time and effort that deserves such respect and/or admiration. Therefore, I am not afraid to show and give it to them. I do hope that one day, the people who are naturally speaking English, can look upon those studying and taking English as their second language at the same level. Some words may be different. Some accent may be present. But the fact of the matter is, English is just an expression of emotions and feelings and thoughts and opinions. It should not be a means of segregating people and classifying them as a lower class or a less educated class. In fact, it should be the opposite. Language should be used to connect people and to integrate different experiences and culture. The fact that people like me are studying English bringing in our experiences and culture to it means we are breathing in new life to English and enriching it. Even people who are not in America who are adopting English to their own language commands such respect. Indian or Singaporean English have become an entity of their own. They bring in new words and means of expressions while retaining English as the backbone of the new language being developed. This is a means of enriching English instead of breaking it down and destroying it. Instead of just carrying the same expressions and words, the exotic experiences and everyday lives of these foreigners are forging with English and therefore, creating a livelier language. People who speak English in their own land while keeping intact their own first languages therefore makes English a more global language and are uniting the world and making people feel closer and more connected with each other.

Cooling Method Of The Transformer Engineering Essay

Cooling Method Of The Transformer Engineering Essay One of the most important and ubiquitous electrical machines is the transformer. It receives power at one voltage and delivers it at another. This conversion aids the efficient long-distance transmission of electrical power form generating stations. Since power lines incur significant power losses, it is important to minimize these losses by the use of high voltages. The same power can be delivered by high-voltage circuits at a fraction of the current required for low-voltage circuits. The design of the magnetic circuit, the core of the transformer, will first be considered. The significance of the no-load behavior of the transformer is explained and of the magnetizing current which exists under all operating condition. The common form of transformer involves a ferromagnetic core in order to ensure high value of magnetic flux linkage. This is also true of the rotating machine. Although transformers are generally associated with power system applications, they also occur in many low power application including electronic circuits. Transformers effect changes of voltage with virtually no loss of power. BASIC PRINCIPLES The transformer is based on two principles: firstly, that an electric current can produce a magnetic field (electromagnetism) and secondly that a changing magnetic field within a coil of wire induces a voltage across the ends of the coil (electromagnetic induction). Changing the current in the primary coil changes the magnetic flux that is developed. The changing magnetic flux induces a voltage in the secondary coil. An ideal transformer is shown in the adjacent figure. Current passing through the primary coil creates a magnetic field. The primary and secondary coils are wrapped around a core of very high magnetic permeability, such as iron, so that most of the magnetic flux passes through both primary and secondary coils. INDUCTION LAW The voltage induced across the secondary coil may be calculated from Faradays law of induction, which states that: Where VS is the instantaneous voltage, NS is the number of turns in the secondary coil and ÃŽÂ ¦ equals the magnetic flux through one turn of the coil. If the turns of the coil are oriented perpendicular to the magnetic field lines, the flux is the product of the magnetic field strength B and the area A through which it cuts. The area is constant, being equal to the cross-sectional area of the transformer core, whereas the magnetic field varies with time according to the excitation of the primary. Since the same magnetic flux passes through both the primary and secondary coils in an ideal transformer, the instantaneous voltage across the primary winding equals Taking the ratio of the two equations for VS and VP gives the basic equation for stepping up or stepping down the voltage ENERGY LOSSES An ideal transformer would have no energy losses, and would be 100% efficient. In practical transformers energy is dissipated in the windings, core, and surrounding structures. Larger transformers are generally more efficient, and those rated for electricity distribution usually perform better than 98%. Experimental transformers using superconducting windings achieve efficiencies of 99.85%,While the increase in efficiency is small, when applied to large heavily-loaded transformers the annual savings in energy losses are significant. A small transformer, such as a plug-in wall-wart or power adapter type used for low-power consumer electronics, may be no more than 85% efficient, with considerable loss even when not supplying any load. Though individual power loss is small, the aggregate losses from the very large number of such devices is coming under increased scrutiny. The losses vary with load current, and may be expressed as no-load or full-load loss. Winding resistance dominates load losses, whereas hysteresis and eddy currents losses contribute to over 99% of the no-load loss. The no-load loss can be significant, meaning that even an idle transformer constitutes a drain on an electrical supply, which encourages development of low-loss transformers (also see energy efficient transformer). Transformer losses are divided into losses in the windings, termed copper loss, and those in the magnetic circuit, termed iron loss. Losses in the transformer arise from: WINDING RESISTANCE Current flowing through the windings causes resistive heating of the conductors. At higher frequencies, skin effect and proximity effect create additional winding resistance and losses. HYSTERESIS LOSSES Each time the magnetic field is reversed, a small amount of energy is lost due to hysteresis within the core. For a given core material, the loss is proportional to the frequency, and is a function of the peak flux density to which it is subjected. EDDY CURRENTS Ferromagnetic materials are also good conductors, and a solid core made from such a material also constitutes a single short-circuited turn throughout its entire length. Eddy currents therefore circulate within the core in a plane normal to the flux, and are responsible for resistive heating of the core material. The eddy current loss is a complex function of the square of supply frequency and Inverse Square of the material thickness. MAGNETOSTRICTION Magnetic flux in a ferromagnetic material, such as the core, causes it to physically expand and contract slightly with each cycle of the magnetic field, an effect known as magnetostriction. This produces the buzzing sound commonly associated with transformers, and in turn causes losses due to frictional heating in susceptible cores. MECHANICAL LOSSES In addition to magnetostriction, the alternating magnetic field causes fluctuating electromagnetic forces between the primary and secondary windings. These incite vibrations within nearby metalwork, adding to the buzzing noise, and consuming a small amount of power. STRAY LOSSES Leakage inductance is by itself largely lossless, since energy supplied to its magnetic fields is returned to the supply with the next half-cycle. However, any leakage flux that intercepts nearby conductive materials such as the transformers support structure will give rise to eddy currents and be converted to heat. There are also radiative losses due to the oscillating magnetic field, but these are usually small. DOT CONVENTION It is common in transformer schematic symbols for there to be a dot at the end of each coil within a transformer, particularly for transformers with multiple windings on either or both of the primary and secondary sides. The purpose of the dots is to indicate the direction of each winding relative to the other windings in the transformer. Voltages at the dot end of each winding are in phase, while current flowing into the dot end of a primary coil will result in current flowing out of the dot end of a secondary coil. TYPE OF TRANSFORMER There are many types of transformer is there one of them is Air-cored transformer. The air-cored transformer may literally consist of two concentric coils which have nothing but air within the coils. This immediately has the advantage that the magnetizing current has exactly the same waveform as the voltage to which it is related. It has the very significant disadvantage that it is difficult to produce the necessary magnetic flux to generate the appropriate e.m.f. LEAKAGE FLUX The ideal transformer model assumes that all flux generated by the primary winding links all the turns of every winding, including itself. In practice, some flux traverses paths that take it outside the windings. Such flux is termed leakage flux, and results in leakage inductance in series with the mutually coupled transformer windings. Leakage results in energy being alternately stored in and discharged from the magnetic fields with each cycle of the power supply. It is not directly a power loss (see Stray losses below), but results in inferior voltage regulation, causing the secondary voltage to fail to be directly proportional to the primary, particularly under heavy load. Transformers are therefore normally designed to have very low leakage inductance. However, in some applications, leakage can be a desirable property, and long magnetic paths, air gaps, or magnetic bypass shunts may be deliberately introduced to a transformers design to limit the short-circuit current it will supply. Leaky transformers may be used to supply loads that exhibit negative resistance, such as electric arcs, mercury vapor lamps, and neon signs; or for safely handling loads that become periodically short-circuited such as electric arc welders. Air gaps are also used to keep a transformer from saturating, especially audio-frequency transformers in circuits that have a direct current flowing through the windings. COOLING METHOD OF TRANSFORMER Oil is used to cool the transformer. It also provide part of the electrical insulation between internal line parts, transformer oil must remain stable at high temperature for an extended period. Very large or high-power transformer may also have cooling fans, oil pumps, and even oil-to-water heat exchangers. Cooling fan is used in transformer. High temperatures will damage the winding insulation. Small transformers do not generate significant heat and are cooled by air circulation and radiation of heat. Power transformers rated up to several hundred kVA can be adequately cooled by natural convective air-cooling, sometimes assisted by fans. Power transformer rated up to a few KVA can be adequately cooled by natural convective air-cooling, sometimes assisted by fans. Some power transformers are immersed in specialized transformer oil that acts both as a cooling medium, thereby extending the lifetime of the insulation transformer. The transformer gets heated due the iron and copper losses occurring in them. It is necessary to dissipate this heat so that the temperature of the winding is kept below the value at which the insulation begins to deteriorate. The cooling of transformer is more difficult than the rotating machines because these machines create a turbulent air flow, which assists in removing the heat generated due losses. Luckily the losses in transformers are comparatively small. According to cooling system there are two types of transformer 1-> ONAN oil natural air natural 2-> ONAF oil natural air forced Oil natural by means a number of radiators with air natural flow. The radiator is fixed to the tank through individual cut-off valves, provided with a handle operate closing device in line with the radiator connector pipe position, indicate open position of the valve. LOSSES IN TRANSFORMER An ideal transformer would have no energy losses, and would therefore be 100% efficient. In practical transformers energy is dissipated in the windings, core , and surrounding structure. TRANSFORMER OIL TEST Transformer oil can give better insulation level to operate the transformer. It also is a coolant to carry the heat away from the electrical transformer windings and iron core to the cooling radiators on the side of the oil filled transformer. If there is no better insulation level, it produced short circuit in the transformer. There for transformer oil should be checked. Normally moisture and other liquids are mixed with oil, the insulation level is reduced. Normally we can see the silica gel for absorb the moisture of transformer. Also there is an equipment to check the insulation level of transformer. TRANSFORMER OIL Transformer oil, or insulating oil, is usually a highly- refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled transformer, some types of high voltage capacitors, fluorescent lamp ballasts, and some types of high voltage switches and circuit breakers. Its functions are to insulate, suppress corona and arcing, and to serve as a coolant. EXPLANATION The oils help cool the transformer. Because it also provides part of the electrical insulation between internal live parts, transformer oil must remain stable at high temperatures for an extended period. To improve cooling of large power transformers, the oil-filled tank may have external radiators through which the oil circulates by natural convection. Very large or high-power transformer may also have cooling fans, oil pumps, and even oil-to-water heat exchangers. Large, high voltage transformers undergo prolonged drying processes, using electrical self-heating, the application of a vacuum, or both to ensure that the transformer is completely free of water of water vapor before the cooling oil is introduced. This helps prevent corona formation and subsequent electrical breakdown under load. Oil filled transformer with a conservator tend to be equipped with Buchholz relays. These are safety devices that detect the build of gases inside the transformer and switch off the transformer. Transformer without conservators is usually equipped with sudden pressure relays, which perform a similar function as the Buchholz relay. The flash point and pour point are 140 degree c and -6 degree c respectively. The dielectric strength of new untreated oil is 12MV/m and after treatment it should be > 24MV/M. Large transformer for indoor use must either be of the dry type, that is, containing no liquid, or use a less-flammable liquid. Well into the 1970, polychlorinated biphenyls were often used as a dielectric fluid since they are not flammable. They are toxic, and under incomplete combustion, can form highly toxic products such as furan. Starting in early 1970, concern about the toxicity of PCBs have led to their banning in many countries. Today, non-toxic, stable silicone-based or fluorinated hydrocarbons are used, where the added expense of a fire-resistant liquid offsets additional building cost for a transformer vault. Combustion- resistant vegetable oil-based dielectric coolants and synthetic pentaerythritol tetra fatty acid, ester is also becoming increasingly common as alternatives to naphthenic mineral oil. Esters are non-toxic to aquatic life, readily biodegradable, and have a lower volatility and higher flash points than minerals oil. COOLING PRODUCTS Transformer oil acts as an insulating and cooling medium in transformers. The insulating oil fills up pores in fibrous insulation and also the gaps between the coil conductors and the spacing between the siding and the tank, and thus increases the dielectric strength of the insulation. A transformer in operation generates heat in the winding, and that heat is transferred to the oil. Heated oil then flows to the radiators by convection. Oil supplied from the radiators, being cooler, cools the winding. There are several important properties such as dielectric strength, flash point, viscosity, specific gravity and pour point and all of them have to be considered when qualifying oil for use in transformers. Normally mineral oil is used, but coconut oil has been shown to possess all the properties needed to function as an environmentally friendly and economic replacement to the mineral oil for this purpose. DIFFERENCE BETWEEN AIR COOLED TRANSFORMER AND OIL IMMERSED TRANSFORMER The basic difference between the air cooled transformer and oil immersed transformer is: If the heat generated in the transformer winding is capable of being swapped by the surrounding ambient air without causing any problem to the performance of the transformer then its normally reffered as Naturally Air Cooled transformer or simply air cooled transformer. However when the capacity of the transformer increases, the heat generated in the winding of the transformer is more and the ambient air normally is inadequate to cool the windings and maintain the performance of the transformer. Its because of this reason the transformer windings are submerged in an oil tank. It has been observed that the hydrogen ions present in oil help to maintain the temperature of the winding of the transformer and thus overall performance of transformer. EFFECT OF FREQUENCY The time-derivative term in Faradays Law shows that the flux in the core is the integral with respect to time of the applied voltage. Hypothetically an ideal transformer would work with direct-current excitation, with the core flux increasing linearly with time. In practice, the flux would rise to the point where magnetic saturation of the core occurs, causing a huge increase in the magnetizing current and overheating the transformer. All practical transformers must therefore operate with alternating (or pulsed) current.