A 5-kVA 480/120-V single-phase transformer is equipped with high-voltage taps so that it may be operated at 480, 456, or 432 V depending on the tap setting. Find the current in the high-voltage winding for each tap setting, the transformer supplying rated kilovoltampere load at 120 V in each case. A) Current at 480V a) 11.57A b) 10.96A c) 10.42A d) none of the above B) Current at 456V a) 11.57A b) 10.96A c) 10.42A d) none of the above C) Current at 432V a) 11.57A b) 10.96A c) 10.42A d) none of the above

A 5-kVA 480/120-V single-phase transformer is equipped with high-voltage taps so that it may be operated at 480, 456, or 432 V depending on the tap setting. Find the current in the high-voltage winding for each tap setting, the transformer supplying rated kilovoltampere load at 120 V in each case. A) Current at 480V a) 11.57A b) 10.96A c) 10.42A d) none of the above B) Current at 456V a) 11.57A b) 10.96A c) 10.42A d) none of the above C) Current at 432V a) 11.57A b) 10.96A c) 10.42A d) none of the above

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.4P: A single-phase 100-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down...

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A two-winding single-phase transformer rated 60kVA,240/1200V,60Hz, has an efficiency of 0.96 when operated at rated load, 0.8 power factor lagging. This transformer is to be utilized as a 1440/1200-V step-down autotransformer in a power distribution system. (a) Find the permissible kVA rating of the autotransformer if the winding currents and voltages are not to exceed the ratings as a two-winding transformer. Assume an ideal transformer. (b) Determine the efficiency of the autotransformer with the kVA loading of part (a) and 0.8 power factor leading.
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