4. A 10-kVA, 440/3300-V, 1-phase transformer, when tested on open circuit, gave the following figures on the primary side : 440V ; 1.3 A ; 115 W. When tested on short-circuit with full-load current flowing, the power input was 140 W. Calculate the efficiency of the transformer at (a) full load unity p.f. (b) one quarter full-load 0.8 p.f. [(a) 97.51% (b) 94.18%]

4. A 10-kVA, 440/3300-V, 1-phase transformer, when tested on open circuit, gave the following figures on the primary side : 440V ; 1.3 A ; 115 W. When tested on short-circuit with full-load current flowing, the power input was 140 W. Calculate the efficiency of the transformer at (a) full load unity p.f. (b) one quarter full-load 0.8 p.f. [(a) 97.51% (b) 94.18%]

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 3.57P: A two-winding single-phase transformer rated 60kVA,240/1200V,60Hz, has an efficiency of 0.96 when...

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