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Design of Three Phase Transformer

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ContentsTypes of transformersPosition of HV & LV windingsCore & Yoke cross-sectional areaImportance of mitered jointsDifferent types of transformers

windingsDifferent methods for cooling of

transformers

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Types of transformersPower transformersDistribution transformersStep-up transformersStep-down transformersCore type transformersShell type transformersSingle phase transformersThree phase transformers

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Position of HV & LV windings

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Core & Yoke cross-sectional area

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Importance of Mitred joints

The Iron loss and the no load current can be decreased if the flux lines are made to flow along the direction of the grain orientation. This is possible in mitred (bevelled) joints are used for cores and yoke as shown in figure.

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Different types of transformers windings1. Cylindrical windings2. Helical windings3. Double helical windings4. Multi-layer helical windings5. Cross-over windings6. Disc & continuous disc windings7. Aluminum windings

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Different methods for cooling of transformers Medium

=> Air=> Gas=> Synthetic oil=> Mineral oil=> Solid insulation=> Water

Circulation=> Natural=> Forced

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Cooling method for DRY type x’mer1) Air natural (AN)2) Air Blast (AB)

Cooling methods for Oil immersed x’mer1) Oil Natural (ON)2) Oil Natural Air Forced (ONAF)3) Oil Natural Water Forced (ONWF)4) Forced Circulation of Oil (OF)

i) Oil Forced Air Natural (OAFN)ii) Oil Forced Air Forced (OFAF)

iii) Oil Forced Water Forced (OFWF)