Choose the correct answer with stating the relationship or reason. 7- The no load current in a transformer lags behind the applied voltage by an angle of about a) 120 degree d) 180 degree b) 75 degree c) 45 degree 8- The hysteresis loss in a transformer is 500 watts at 50 Hz. Its loss at 80 Hz will be a) 312.5 watts b) 500 watts c) 200 watts 9- Power transformers are designed to have maximum efficiency at d) 800 watts a) nearly full load b) 70% full load c) 50% full load d) no load 10- A transformer operates maximum efficiently at 3/4th full load. Its iron (Pi) and copper loss (Pcu) are related as: a) Pi=1.778 Pcu b) Pi=1.333 Pcu c) Pi=0.75 Pcu d) Pi-0.5625 Peu

Choose the correct answer with stating the relationship or reason. 7- The no load current in a transformer lags behind the applied voltage by an angle of about a) 120 degree d) 180 degree b) 75 degree c) 45 degree 8- The hysteresis loss in a transformer is 500 watts at 50 Hz. Its loss at 80 Hz will be a) 312.5 watts b) 500 watts c) 200 watts 9- Power transformers are designed to have maximum efficiency at d) 800 watts a) nearly full load b) 70% full load c) 50% full load d) no load 10- A transformer operates maximum efficiently at 3/4th full load. Its iron (Pi) and copper loss (Pcu) are related as: a) Pi=1.778 Pcu b) Pi=1.333 Pcu c) Pi=0.75 Pcu d) Pi-0.5625 Peu

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 3.33P: Consider the three single-phase two-winding transformers shown in Figure 3.37. The high-voltage...

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