Multiple choice questions: 1- A voltages of 50Hz transformer are 1500 V on primary and 600 V on the secondary. It has 1.5 V per turn. Then the number of turns on primary and secondary are a) 20 and 8 b) 100 and 10 c) 1000 and 120 d)1000 and 400 e) none of the previous. 2-A 600/200 V single phase transformer is supplying a load of 60 A at a p.f of 0.707 lag. The no load current is 3A at 0.2 P.f. lag. Then the primary current is a) 63A b) 22.56A c) 69A d)24 e) 21.55 f) none of the previous. 3- The silicon ratio in transformer iron cannot be increased greater than 5% because of a) the iron loss will increase b) the hysteresis loss will increase c) the eddy current loss will increase d) none of the previous ICVI =400Y and the wattmeter read 800W at no load test then the value of Ro is

Multiple choice questions: 1- A voltages of 50Hz transformer are 1500 V on primary and 600 V on the secondary. It has 1.5 V per turn. Then the number of turns on primary and secondary are a) 20 and 8 b) 100 and 10 c) 1000 and 120 d)1000 and 400 e) none of the previous. 2-A 600/200 V single phase transformer is supplying a load of 60 A at a p.f of 0.707 lag. The no load current is 3A at 0.2 P.f. lag. Then the primary current is a) 63A b) 22.56A c) 69A d)24 e) 21.55 f) none of the previous. 3- The silicon ratio in transformer iron cannot be increased greater than 5% because of a) the iron loss will increase b) the hysteresis loss will increase c) the eddy current loss will increase d) none of the previous ICVI =400Y and the wattmeter read 800W at no load test then the value of Ro is

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 3.26P: A bank of three single-phase transformers, each rated 30MVA,38.1/3.81kV, are connected in Y- with a...

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For a short-circuit test on a 2-winding transformer, with one winding shorted, can you apply the rated voltage on the other winding? (a) Yes (b) No
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A 23/230-kV step-up transformer feeds a three-phase transmission line, which in turn supplies a 150-MVA,0.8 lagging power factor load through a step-down 230/23-kV transformer. The impedance of the line and transformers at 230kVis18+j60. Determine the tap setting for each transformer to maintain the voltage at the load at 23 kV.
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A bank of three single-phase transformers, each rated 30MVA,38.1/3.81kV, are connected in Y- with a balanced load of three 1, Y-connected resistors. Choosing a base of 90MVA,66kV for the high-voltage side of the three-phase transformer. spify the base for the low-voltage side. Compute the per-unit resistance of the load on the base for the low-voltage side. Also, determine the load resistance in ohms referred to the high-voltage side and the per-unit value on the chosen base.
Rework Problem 3.14 if the transformer is delivering rated load at rated secondary voltage and at (a) unity power factor, (b) 0.8 power factor leading. Compare the results with those of Problem 3.14. -
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