## Output of an Autotransformer and Saving of Copper in Transformer

Manish Kumar Saini

Updated on 12-Aug-2021 13:19:42

Working of AutotransformerThe connection diagram of an ideal step-down autotransformer is shown in the figure. In which the winding ab is the primary winding having N1 turns and the winding bc is the secondary winding having N2 turns. Here, the current I1 is the input primary current and the current ... Read More

## Open Circuit and Short Circuit Test of Transformer

Manish Kumar Saini

Updated on 12-Aug-2021 13:12:18

The open-circuit test and the short-circuit test being performed on a transformer to determine the circuit parameters, efficiency and the voltage regulation without actual loaded of the transformer. The open-circuit and short-circuit tests give more accurate results than those are obtained by performing the measurements on a fully loaded transformer. ... Read More

## How Does a Three-Phase Autotransformer Function?

Manish Kumar Saini

Updated on 12-Aug-2021 12:55:01

A three-phase star-connected autotransformer is shown in the figure. The three-phase autotransformers are used for small ratios of transformation.In practice, the star connected three-phase autotransformers are used and the delta connected autotransformers are avoided. The primary application of three phase autotransformers is for interconnecting two power systems of different voltage ... Read More

## Harmonics in Three Phase Transformers

Manish Kumar Saini

Updated on 12-Aug-2021 12:53:14

The non-sinusoidal nature of the magnetising current in a three phase transformer produces some undesirable phenomena. The phase magnetising current should contain third and higher order harmonics which is necessary to produce a sinusoidal flux.If the phase voltage across each phase is sinusoidal, then the phase magnetising currents are given ... Read More

## Double-Star Connection of Transformers – Three-to-Six Phase Transformation

Manish Kumar Saini

Updated on 12-Aug-2021 12:45:52

The rectifiers are used to convert alternating current (AC) to direct current (DC). The advantages of increased number of phases of the AC supply are given as follows −A smoother waveform is obtained on the DC side as the number of phases of the AC supply is increased.The objectionable harmonics ... Read More

## Double-Delta Connection of Transformers – Three-to-Six Phase Transformation

Manish Kumar Saini

Updated on 12-Aug-2021 12:42:56

The rectifiers are used to convert alternating current (AC) to direct current (DC). The advantages of increased number of phases of the AC supply are given as follows −A smoother waveform is obtained on the DC side as the number of phases of the AC supply is increased.The objectionable harmonics ... Read More

## Determination of Voltage Regulation of a Three Winding Transformer

Manish Kumar Saini

Updated on 12-Aug-2021 12:38:22

The procedure for determining the voltage regulation of a 3-winding transformer is given as follows −Step 1Determine the kVA in each winding (primary, secondary and tertiary) for the given load. Determine x for each winding. Where, x is the ratio of actual kVA loading of the winding to the base ... Read More

## Delta-Star Connection of Transformer – Three-Phase Transformer Connection

Manish Kumar Saini

Updated on 12-Aug-2021 12:34:13

In case of the delta-star connection of a 3-phase transformer, the primary winding is connected in delta while the secondary winding is connected in star (see the figure).Primary Winding − As the primary winding is connected in delta. Hence, the line voltage and the phase voltage on the primary side ... Read More

## Conversion of a Two Winding Transformer into an Autotransformer

Manish Kumar Saini

Updated on 12-Aug-2021 12:30:29

A conventional two-winding transformer can be converted into an autotransformer as shown in the figures given below. It can be converted into a step-up autotransformer by connecting the two windings electrically in series with additive polarities. If the windings are connected electrically in series with subtractive polarities, then a step-down ... Read More

## Back-to-Back Test (Sumpner’s Test) on Transformer

Manish Kumar Saini

Updated on 12-Aug-2021 12:24:49

A full-load test on the large transformer is to be conducted to determine the maximum temperature rise of the transformer which is called as back-to-back test. The back-to-back test is also known as Sumpner’s test or regenerative test.In case of small transformers, the full-load test is conveniently possible, but for ... Read More