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Audio Frequency Transformer

Audio Frequency Transformer: Audio Frequency Transformer is used at the output stage of Audio Frequency electronic amplifier for matching the load to the output impedance of the power amplifier stage. Here the load is fixed but the frequency is variable over a band (audio, 20 Hz to 20 kHz), the response being the ratio V2/V1. …

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Current and Voltage Transformer

Current and Voltage Transformer: Current and Voltage Transformer – These transformers are designed to meet the specific need of measurement and instrumentation systems, which accept voltages in the range of 0-120 V and currents upto 5 A. Power system voltages can be as high as 750 kV and currents up to several tens of kA. …

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Tap Changing Transformer

Tap Changing Transformer Tap Changing Transformer -Voltage variation in power systems is a normal phenomenon owing to the rapid growth of industries and distribution network. System voltage control is therefore essential for: Adjustment of consumers’ terminal voltage within prescribed limits. Control of real and reactive power flow in the network. Periodical adjustment (1-10%) to check …

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Phase Conversion

Phase Conversion: Three/Two-phase Conversion (Scott Connection): Phase conversion from three to two phase is needed in special cases, such as in supplying 2-phase electric arc furnaces. The concept of 3/2-phase conversion follows from the voltage phasor diagram of balanced 3-phase supply shown in Fig. 3.61(b). If the point M midway on VBC could be located, …

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Three Winding Transformer

Three Winding Transformer: Three Winding Transformer may be built with a third winding, called the tertiary, in addition to the primary and secondary. Various purposes which dictate the use of a tertiary winding are enumerated below: To supply the substation auxiliaries at a voltage different from those of the primary and secondary windings. Static capacitors …

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Parallel Operation of Transformer

Parallel Operation of Transformer: When the load outgrows the capacity of an existing transformer, it may be economical to install another one in parallel with it rather than replacing it with a single larger unit. Also, sometimes in a new installation, two units in parallel, though more expensive, may be preferred over a single unit …

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Back to Back Test of Transformer

Back to Back Test of Transformer: The Back to Back Test of Transformer which consists of two parts namely, Back to Back Test on Three Phase Transformer Back to Back Test on Delta/Delta Transformer Back to Back Test on Three Phase Transformer: Fig. 3.52(a) shows the connection arrangement for the Back to Back Test of …

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Three phase Transformer Bank of Single phase Transformers

Three phase Transformer Bank of Single phase Transformers: The different Three phase Transformer Bank of Single phase Transformers are namely, Delta/delta connection: The supply voltage provides only sinusoidal magnetizing current so that core flux is flat-topped; but the third-harmonic emfs induced (cophasal) cause circulating currents in deltas restoring the flux to almost sinusoidal. The third-harmonic …

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Choice of Transformer Connection Diagram

Choice of Transformer Connection Diagram: The different choice of Transformer Connection Diagram are namely, Star/star: This is economical for small HV transformers as it minimizes the turns/phase and winding insulation. A neutral connection is possible. However, the Y/Y connection is rarely used because of difficulties associated with the exciting current. Delta/delta: This suits large LV …

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