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Special Transformers and Applications

Special Transformers and Applications

Instrument Transformers It is unsafe to connect instruments and allied equipment to high voltage and current circuits, so instrument transformers are used to reduce these voltages and currents to safer, more convenient values. The two types of instrument transformers used are potential and current transformers. Figure 1(overleaf) shows how a voltmeter, …

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Parallel Operation of Transformers

Transformer Compatibility When connecting three-phase transformers in parallel, the two transformers should have the same transformation ratio, phase sequence and internal phase shifts. The two transformers are assumed to have their primary windings connected to the same supply. Care must be taken to ensure that the transformers have compatible internal …

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Understanding Transformer Polarity

Understanding Transformer Polarity

It is sometimes necessary to operate two or more transformers in parallel and to do so, not only must the output voltages be equal but the instantaneous polarities must be the same. Single-Phase Transformers Equal voltages When two unequal voltage sources are connected in parallel, the phasor difference between the …

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Tap Changing Transformer in Power System

Tap Changing Transformer in Power System

With long-distance transmission lines the characteristics of the line affect the voltage at the delivery end of the line. The conductors have an inherent capacitance between them and there is an inductive effect due to the length of the parallel conductors. Each conductor also has a fixed value of resistance. …

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Transformer Losses and Efficiency

Transformer Losses and Efficiency | Iron & Copper Losses in Transformer

Iron Losses Eddy Currents The magnetic core of a transformer consists of many laminations of a high-grade silicon steel of a definite thickness. The power absorbed by the core of a transformer is due to eddy currents and hysteresis and is called iron losses. When the alternating flux cuts the …

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Transformer Operating Principle

Transformer Operating Principle | No-Load and On-Load Condition Phasor Diagram

The primary and secondary windings and the magnetic core of the transformer are all stationary with respect to each other. The primary winding is connected to an alternating supply causing an alternating magnetic flux to be produced in the magnetic core (i.e. the magnitude of the flux is changing with …

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Transformation Ratio of Transformer

Transformation Ratios of Transformer

This article covers various transformation ratios of a transformer such as voltage (turns) ratio, current ratio, and impedance ratio (matching) in detail along with solved examples. Voltage (Turns) Ratio The mutual flux is common to each winding. Therefore, it must induce the same voltage per turn in each winding. If V1′ is …

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Three Phase Transformer Connections

Delta-Wye Three Phase Transformer Phasor Diagram

In this section, we’ll review the operating characteristics of basic delta-delta, wye-wye, delta-wye and wye-delta connections of the transformer. The construction of a three-phase transformer can be represented as shown in Figure 1. The shell type core has three sets of primary and secondary windings. How these windings are connected …

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Single-Phase Transformer | Construction | Theory

single phase transformer.

In the same way that single-phase AC and three-phase AC are different, although both are alternating current electricity, single-phase and three-phase transformers cannot be interchanged. Nevertheless, most of what can be said for single-phase transformers is later on extended to three-phase transformers because they work based on the same principle. …

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Power Transformer Differential Protection

Transformer differential protection diagram

A power transformer’s main task is to transform an electrical power from one voltage level to the other voltage level. A power transformer is the most important part of the electrical system as well as well the most expensive part. The function of all other electrical equipment (e.g. circuit breakers, …

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Buck-Boost Transformer Working Principle

An isolation transformer can be wired as an autotransformer in a buck configuration

A buck-boost transformer is a type of transformer which is primarily used to adjust the voltage level applied to various electric equipment. Buck-boost transformers are utilized in in several applications such as uninterruptible power supplies (UPS) units for computers. When an existing AC electrical circuit suffers from excessive voltage drop …

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Three Phase Transformer Construction

2500 kVA power transformer.

A transformer consists of two or more electrical windings that are linked together by a magnetic field. Except for special-purpose transformers, the coupling is enhanced with a ferromagnetic core. Transformers are often drawn as shown in Figure 1, with the primary coil on one leg and the secondary coil on …

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Autotransformer: Working, Advantages, Disadvantages

Autotransformer Definition The autotransformer has a single winding on an iron core. One of the coil terminals is common to both input and output, and the other output terminal is movable so that it can make contact with any turn on the winding. Step-Up/ Step-Down Autotransformer An autotransformer can be …

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