"Electrical machines/ I need a complete and clear solution for all sub -questions of a single question. Thank you." 4-A single phase transformer has maximum efficiency at 75% of full load. Its copper loss at fullload should bea) equal to core loss, b) less than core loss. c) more than core loss, d) equal to 75% of core loss5- The efficiency of a transformer is 98 % at full-load with 0.8 lagging power factor, what will bethe efficiency when supplies full-load with 0.8 leading power factor?a) less than 98%, b) 98%, c) more than 98 %,6-During short circuit test of a transformerd) none of the abovea) primary is supplied rated voltage, b) primary is supplied full load current at rated voltagec) primary is supplied full load current with small voltage, d) primary is supplied rated kVA7-A 500kVA transformer has iron loss of 500W and copper losses of 2000W at full load. what isthe kVA rating should the transformer operates to achieve maximum efficiency?a)250KVA55) 500KVA,1000KVA125KVA

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4-A single phase transformer has maximum efficiency at 75% of full load. Its copper loss at full load should be a) equal to core loss, b) less than core loss. c) more than core loss, d) equal to 75% of core loss 5- The efficiency of a transformer is 98 % at full-load with 0.8 lagging power factor, what will be the efficiency when supplies full-load with 0.8 leading power factor? a) less than 98 %, b) 98%, c) more than 98 %, d) none of the above 6-During short circuit test of a transformer a) primary is supplied rated voltage, b) primary is supplied full load current at rated voltage c) primary is supplied full load current with small voltage, d) primary is supplied rated kVA 7-A 500kVA transformer has iron loss of 500W and copper losses of 2000W at full load. what is the kVA rating should the transformer operates to achieve maximum efficiency? a)250KVA X) 500KVA, 1000KVA 125KVA

4-A single phase transformer has maximum efficiency at 75% of full load. Its copper loss at full load should be a) equal to core loss, b) less than core loss. c) more than core loss, d) equal to 75% of core loss 5- The efficiency of a transformer is 98 % at full-load with 0.8 lagging power factor, what will be the efficiency when supplies full-load with 0.8 leading power factor? a) less than 98 %, b) 98%, c) more than 98 %, d) none of the above 6-During short circuit test of a transformer a) primary is supplied rated voltage, b) primary is supplied full load current at rated voltage c) primary is supplied full load current with small voltage, d) primary is supplied rated kVA 7-A 500kVA transformer has iron loss of 500W and copper losses of 2000W at full load. what is the kVA rating should the transformer operates to achieve maximum efficiency? a)250KVA X) 500KVA, 1000KVA 125KVA

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 3.9P

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Similar questions

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
An ideal transformer has no real or reactive power loss. (a) True (b) False
Consider an ideal transformer with N1=3000andN2=1000 turns. Let winding 1 be connected to a source whose voltage is e1(t)=100(1| t |)volts for 1t1ande1(t)=0 for | t |1 second. A2- farad capacitor is connected across winding 2. Sketch e1(t),e2(t),i1(t),andi2(t) versus time t.
In developing per-unit circuits of systems such as the one shown in Figure 3.10. when moving across a transformer, the voltage base is changed in proportion to the transformer voltage ratings. (a) True (b) False
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.
A single-phase, 50-kVA,2400/240-V,60-Hz distribution transformer has the following parameters: Resistance of the 2400-V winding: R1=0.75 Resistance of the 240-V winding: R2=0.0075 Leakage reactance of the 2400-V winding: X1=1.0 Leakage reactance of the 240-V winding: X2=0.01 Exciting admittance on the 240-V side =0.003j0.02S (a) Draw the equivalent circuit referred to the high-voltage side of the transformer. (b) Draw the equivalent circuit referred to the low-voltage side of the transformer. Show the numerical values of impedances on the equivalent circuits.
The ideal transformer windings are eliminated from the per-unit equivalent circuit of a transformer. (a) True (b) False
For developing per-unit equivalent circuits of single-phase three-winding transformer, a common Sbase is selected for all three windings and voltage bases are selected in proportion to the rated voltage of the windings (a) True (b) False
For an ideal 2-winding transformer, the ampere-turns of the primary winding, N1I1 is equal to the ampere-turns of the secondary winding, N2I2 (a) True (b) False
For the transformer in Problem 3.10. The open-circuit test with 11.5 kV applied results in a power input of 65 kW and a current of 30 A. Compute the values for GcandBm in siemens referred to the high-voltage winding. Compute the efficiency of the transformer for a load of 10 MW at 0.8 p.f. lagging at rated voltage.
The symbol shown is a(n) a. iron core transformer. b. auto transformer. c. current transformer. d. air core transformer.
An ideal transformer with N1=1000andN2=250 is connected with an impedance Z22 across winding 2. If V1=10000VandI1=530 A, determine V2,I2,Z2, and the impedance Z2, which is the value of Z2 referred to the primary side of the transformer.