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A Proposed Design - Essay Example

We would like to express our utmost gratitude to the following people who helped us in accomplishing this project design in spite of difficulties that we had in terms of chemical aspects and time management. Without these people, this project design would be impossible to accomplish. First of all, we would like to thank Our Almighty God for giving us strength and wisdom in accomplishing this project design. We would like to thank our project adviser, Eng.

Survive Baggy, for giving us the opportunity in accomplishing this project design and for sharing his words of wisdom to us in order for us to become inspired not only in doing this project design but also in learning different things in life. We would like to thank our parents who allowed us to have overtime in doing this reject design. Lastly, we would like to thank our closest friends who prayed for us, guide and give us the words of wisdom so that we will be inspired not only in doing this project design but also in learning different things in life.

Survive R. Baggy Professor Technological Institute of the Philippines Dear Eng. Baggy: In compliance with the fulfillment of the requirements on the subject “AC Apparatus”, the proponents would like to present the proposal entitled “kava 13. Xv/IV Core Type Distribution Transformer with Cruciform Section”, in accordance with your instructions. The main purpose of the document is to design a distribution transformer that operates at very high efficiency. We hope that this proposal will meet your approval. Very truly yours, Alexandra, Sooner P. Caretakers, Runnel C.

ABSTRACT The type of transformer that is designed in this proposal is a core type distribution transformer with cruciform section. It has a capacity of 75 kava operating at 60 Hz’s, primary voltage of 13. 8 xv and at secondary voltage of IV to IV which indicates that it is a center-tapped transformer. The proposed transformer is designed for high operating efficiencies at unity power factor starting from quarter dad condition to 25% overload condition. The all-day efficiency at 4 hours full load is also high. The proposed transformer is also designed for very low level voltage regulation starting from 0. Power factor up to unity power factor. The approximate temperature rise of oil in tank is ICC. The tabulation below represents the comparison between the guaranteed efficiencies, losses and voltage regulation based from the actual performance of the transformer and the calculated efficiencies, losses and voltage regulations based from this design project.

A common transformer usually composed of laminated core, primary windings and secondary windings at the opposite sides of the core. The laminated core is usually the heart of the transformer because it serves as the bridge for transferring electrical energy from one circuit to another through electromagnetic induction. The primary winding is usually connected to the source while the secondary winding is usually connected to the load. The transformers work only in AC. Its capacity is rated in kava. The power reduced in primary winding is the same as that of the secondary winding.

The ability of the transformer to change the voltage is measured through its ratio of transformation. It is equal to either the ratio of primary voltage and secondary voltage, the ratio of primary turns and secondary turns or the ratio of secondary current and primary current. There are two types of transformer in terms of changing the voltage; step-up transformer and step-down transformer. The step-up transformer change the voltage from low to high while the step-down transformer change the voltage from high to low. There are three types of transformer in terms of opacity.

First is the power transformer which has usually high capacity and located medium capacity that distributes the electrical power to the customers. Third is the household transformer that is found on appliances and devices. There are five types of transformers in terms of use. These are autotransformer, polyphony transformers, leakage transformers, audio transformers and instrument transformers. There are four types of core that are used in transformer. These are laminated steel cores, solid cores, tutorial cores and air cores.

Laminated steel cores are usually used in power and audio frequency transmissions. Solid cores are used for switch-mode power supplies and for transmitting very high frequencies. Tutorial cores are the improvised version of laminated steel cores. Air cores are the ones that eliminated the losses and are frequently used in radio-frequency applications. There are six types of energy losses in transformers. These are winding resistance, hysterics losses, eddy current losses, microinstruction, mechanical losses and stray losses.

In any transformers, there is a little percentage of voltage regulation that exist in the output. Voltage regulation in transformers is the percentage rise of voltage hen the transformer load is removed. There are convenient ways of determining the amount of losses in transformers. The first one is the short circuit test that is used in determining the full-load copper loss of transformer. The second one is the open circuit test that is used in determining the core loss of transformer. Losses in the transformer are of the order of 1% of its full load k rating.

These losses get converted in the heat thereby the temperature of the windings, core, oil and the tank rises. The heat is dissipated from the transformer tank and the radiator in to the atmosphere. Transformer cooling helps in maintaining the temperature rise of various parts within permissible limits. In case of Transformer, Cooling is provided by the circulation of the oil. Transformer Oil acts as both insulating material and also cooling medium in the transformer. For small rating transformers heat is removed from the transformer by natural thermal convection.

For large rating transformers this type of cooling is not sufficient, for such applications forced cooling is used. As size and rating of the transformer increases, the losses increase at a faster rate. So oil is circulated in the transformer by means of oil pumps. Within the tank the oil is made to flow through the space between the coils of the windings. Several different combination of natural, forced, air, oil transformer cooling methods are available. The choice of picking the right type of transformer cooling method for particular application depends on the factors such as rating, size, and location.

Improvement in transformer performance, particularly in small distribution units, is made possible by the use of a special silicon-iron alloy that possesses permanent managing characteristics. This material differs from ordinary silicon steel not so much in the elements it contains as in how it is made. In its manufacture it is rolled so that the individual magnetic crystals are “oriented”, that is, lined up with their cube edges parallel to each other and to the direction of rolling, like bricks in a wall; this is in contrast to the pattern incidental to ordinary silicon steel.

The effect of such crystal orientation is to permit the steel to carry more flux with the same applied magnetized force than it could if the crystals were haphazardly placed. This means simply that the knee of the magnification curve is lifted to a higher flux density, with he result that increased flux densities, about 30 per cent more, are possible without the strips be sheared parallel to the grain of rolling; moreover, a construction must be employed that causes the flux paths to be with the grain.

This is accomplished in several ways by different manufacturers, in one of which a special machine winds the steel ribbon spirally through the windings openings and the outside of the coils. Transformers constructed in this way are smaller in size for a given kilovolt-ampere rating, present a more rigid core, have lower iron losses at higher flux densities, have educed strains in the iron that are normally set up by clamps and are cheaper to manufacture. In parallel with the improvement in the core material itself, a new type of coating has been developed.