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Answer :

Natural air cooling is generally restricted for transformers up to 1.5 MVA .

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Last Answer : Natural oil cooling is used for transformers up to a rating of 3000 kVA.

Last Answer : A common method of cooling a power transformer is oil cooling.

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Last Answer : Ans. Transformers requires cooling as they get heated up due to various losses taking place in the transformer. (like iron of copper losses) Following are the methods of cooling of transformer. a. Natural ... . Forced oil air Natural Cooling (OFAN). d. Forced oil and forced Air cooling (OFAF).

Last Answer : Distribution transformers are generally designed for maximum efficiency around 50% load.

Last Answer : Power transformers are generally designed to have maximum efficiency around near full-load.

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Last Answer : If the percentage impedances of the two transformers working in parallel are different, then parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load.

Description : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?

Last Answer : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in loading of the transformers not in proportion to their kVA ratings.

Last Answer : Short circuit test on transformers is conducted to determine copper losses.

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Last Answer : Friction losses windage losses 

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Last Answer : The efficiency of two identical transformers under load conditions can be determined by back-to-back test.

Description : The efficiencies of transformers compared with that of electric motors of the same power are?

Last Answer : Transformers have high efficiency than the same ratted motors

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Last Answer : Harmonics in transformer result in increased core losses, increased I2R losses, and magnetic interference with communication circuits.

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Last Answer : A

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