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 […]
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An autotransformer is a transformer which has part of its winding common to the primary and secondary circuits. Fig. 1(a) shows the circuit for a double-wound transformer and Fig. 1(b) that for an auto transformer. The latter shows that the secondary is actually part of the primary, the current in the secondary being (I2-I1). Since
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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The excitation control method is satisfactory only for relatively short lines. However, it is not suitable for long lines as the voltage at the alternator terminals will have to be varied too much in order that the voltage at the far end of the line may be constant. Under such situations, the problem of voltage
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Transformers are susceptible to damage by secondary short-circuit currents having magnitudes that can be many times rated load current. The damage results from the following effects: >> The I2R losses in the winding conductors are increased by the square of the current. This increases the temperature rise of the windings. >> Because protective devices limit the duration of
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