Sumpner Test of Transformer: While OC and SC tests on a transformer yield its equivalent circuit parameters, these cannot be used for the ‘heat run’ test wherein the purpose is to determine the steady temperature rise if the transformer was fully loaded continuously; this is so because under each of these tests the power loss […]
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Transformer Testing Methods: Two chief difficulties which do not warrant the Transformer Testing Methods by direct load test are: Large amount of energy has to be wasted in such a test, It is a stupendous (impossible for large transformers) task to arrange a load large enough for direct loading. Thus performance characteristics of a transformer
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Different types of losses in transformer: The transformer has no moving parts so that its efficiency is much higher than that of rotating machines. Different types of losses in transformer are enumerated below: Core Loss in a Transformer: These are hysteresis and eddy-current losses resulting from alternations of magnetic flux in the core. Their nature
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Transformer Nameplate Rating: Transformer Nameplate Rating Details – The voltage ratio is specified as V1 (rated)/V2 (rated). It means that when voltage V1 (rated) is applied to the primary, the secondary voltage on full load at specified pf is V2 (rated). The ratio V1 (rated)/V2 (rated) is not exactly equal to N1/N2, because of voltage
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Phasor Diagram of Transformer: For the approximate equivalent circuit of Phasor Diagram of Transformer is shown in Fig. 3.16(b) The phasor diagram corresponding to this equation is drawn in Fig. 3.17(a) for the lagging power factor (phase angle Φ between V2 and I) and in Fig. 3.17(b) for the leading power factor (pf). It is
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Approximate Equivalent Circuit of Transformer: Approximate Equivalent Circuit of Transformer – In constant frequency (50 Hz) power transformers, approximate forms of the exact T-circuit equivalent of the transformer are commonly used. With reference to Fig. 3.14(c), it is immediately observed that since winding resistances and leakage reactances are very small, V1 ≈ E1 even under conditions
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Real Transformer On Load Condition | Equivalent Circuit: Figure 3.11 shows a Real Transformer On Load Condition. Both the primary and secondary have finite resistances R1 and R2 which are uniformly spread throughout the winding; these give rise to associated copper (I2R) losses. While a major part of the total flux is confined to the
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Ideal Transformer on Load: In order to visualize the effect of flow of secondary current in a transformer, certain idealizing assumptions will be made which are close approximations for a practical transformer. A transformer possessing these ideal properties is hypothetical (has no real existence) and is referred to as the Ideal Transformer on Load. It
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Phasor Diagram of Transformer on No Load: Figure 3.5 shows the schematic diagram of a Phasor Diagram of Transformer on No Load with Two Winding, i.e. the secondary terminals are open while the primary is connected to a source of constant sinusoidal voltage of frequency fHz. The simplifying assumption that the resistances of the windings
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Forced Cooling in Transformer: Forced Cooling in Transformer – For transformer sizes beyond 5 MVA additional cooling would be needed which is achieved by supplementing the tank surface by a separate radiator in which oil is circulated by means of a pump. For better cooling oil-to-air heat exchanger unit is provided as shown in Fig.
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