Transformers reduce the voltage of the electricity supplied by the utility to a level suitable for use by the electric equipment. Since all of the electricity used by a company passes through a transformer, even a small efficiency improvement will result in significant electricity savings. High-efficiency transformers are now available that can reduce total electricity […]
LOSS AND EFFICIENCY AND COSTING OF TRANSFORMER Read More »
To perform the economical analysis of transformer, it is necessary to calculate its life cycle cost, sometimes called total cost of ownership, over the life span of transformer or, in other words, the capitalized cost of the transformer. All these terms mean the same – in one formula, costs of purchasing, operating and maintaining the
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TRANSFORMER A transformer is an extended version of an inductor. The flux that is created inside the inductor is used here to induce voltages at other coil, which is termed as secondary coil. If the rate of change of flux can induce voltage across the primary coil, from which it is created, then it is
TYPES OF TRANSFORMERS Read More »
The magnetic flux ϕ set up in the core of a transformer when an alternating voltage is applied to its primary winding is also alternating and is sinusoidal. Let ϕm be the maximum value of the flux and f be the frequency of the supply. The time for 1 cycle of the alternating flux is
EMF EQUATION OF A TRANSFORMER Read More »
Some small transformers for low-power applications are constructed with air between the two coils. Such transformers are inefficient because the percentage of the flux from the first coil that links the second coil is small. The voltage induced in the second coil is determined as follows. E=NdΦ/dt108 where N is the number of turns in
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Sometimes it is desired to control the voltage of a transmission line at a point far away from the main transformer. This can be conveniently achieved by the use of a booster transformer as shown in Figure 1. The secondary of the booster transformer is connected in series with the line whose voltage is to
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Figure shows diagrammatically auto-transformer tap changing. Here, a mid-tapped auto-transformer or reactor is used. One of the lines is connected to its mid-tapping. One end, say a of this transformer is connected to a series of switches across the odd tappings and the other end b is connected to switches across even tappings. A short-circuiting
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External faults are those faults or hazards that occur outside the transformer. These hazards present stresses on the transformer that may be of concern and may shorten the transformer life. These faults include the following. • OVER LOADS Overloads cause the transformer to overheat and have the potential to cause permanent damage or loss of
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Even though the basic functions of the oil used in transformers are (a) heat conduction and (b) electrical insulation, there are many other properties which make a particular oil eminently suitable. Organic oils of vegetative or animal origin are good insulators but tend to decompose giving rise to acidic by-products which attack the paper or
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THERMAL CONSIDERATIONS The losses in the windings and the core cause temperature rises in the materials. This is another important area in which the temperatures must be limited to the long-term capability of the insulating materials. Refined paper is still used as the primary solid insulation in power transformers. Highly refined mineral oil is still
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