Q2) put ( v) or (x) for the following and correct the wrong :1-the connection Delta-Delta is the choice for large L.V. transformer its remark is smallload unbalanced can be tolerated.2-Armature Cu lossstray or rotational losses Copper lossesShunt field Cu IcsSeries field Cu lossHysteresis lossLosses in a d.c, machineIron lossesEddy current lossFrictionMechanical lossesWindage3-For a loaded dc generator, Geometrical Neutral Axis will be shifted in the direction ofthe rotation. On the other hand, for a loaded dc motor, Geometrical Neutral Axis will beshifted in the direction opposite to that of the rotation4-The approximate equivalent circuit referred to the secondaryReaXe5- The permittivity of dielectric materials are much smaller than the permeability offerromagnetic materials it is more advantageous to use electromagnetic field as themedium for electromechanical energy conversion.6- Voltage regulation =[(Vno load -Vfull load )/Vno load ] in single-phase step-uptransformer7-to reduce eddy current loss the yoke is built up of laminations sheet steel8-The critical field circuit resistance should be larger than the field circuit resistance andthe critical speed should be less than the speed of the rotation9- The O.C.C. curve lies above internal characteristic curve.10-To determine the internal and external load characteristics of a DC shunt generator themachine is allowed to build up its voltage before applying any external load then, it isgradually loaded with capacitive load and readings are taken at suitable intervals.11- the most useful connections are (star-star), (delta-delta), (star-delta), (delta -star),(open- delta or T-T connection ) and (Scott connection or v connection).12-if series winding amp-turns are adjusted so that, increase in load current causesdecrease in terminal voltage then the generator is called to be under compounded.13- Pm = wT= 2nT= 2nF+r14-f = frequency of magnetic reversals = NP/120 where N is in r.p.s15- In cumulative compound motor the flux produced by both the windingsPsh=@r+ Pse

As per the guidelines given, We can only provide the solution of the first three questions in…

Q2) put ( v) or (x) for the following and correct the wrong : 1-the connection Delta-Delta is the choice for large L.V. transformer its remark is small load unbalanced can be tolerated. 2- Armature Cu loss stray or rotational losse Copper lesses - Shunt field Cu Icss Series field Cu loss Hysteresis loss Losses in a d.c. machine • Iron losses Eddy current loss Friction Mechanical losses- Windage 3-For a loaded dc generator, Geometrical Neutral Axis will be shifted in the direction of the rotation. On the other hand, for a loaded dc motor, Geometrical Neutral Axis will be shifted in the direction opposite to that of the rotation

Q2) put ( v) or (x) for the following and correct the wrong : 1-the connection Delta-Delta is the choice for large L.V. transformer its remark is small load unbalanced can be tolerated. 2- Armature Cu loss stray or rotational losse Copper lesses - Shunt field Cu Icss Series field Cu loss Hysteresis loss Losses in a d.c. machine • Iron losses Eddy current loss Friction Mechanical losses- Windage 3-For a loaded dc generator, Geometrical Neutral Axis will be shifted in the direction of the rotation. On the other hand, for a loaded dc motor, Geometrical Neutral Axis will be shifted in the direction opposite to that of the rotation

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 3.14P: A single-phase 50-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down...

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Similar questions

An ideal transformer has no real or reactive power loss. (a) True (b) False
Consider a source of voltage v(t)=102sin(2t)V, with an internal resistance of 1800. A transformer that can be considered as ideal is used to couple a 50 resistive load to the source. (a) Determine the transformer primary-to-secondary turns ratio required to ensure maxi mum power transfer by matching the load and source resistances. (b) Find the average power delivered to the load, assenting maximum power transfer.
Consider Figure 3.4. For an ideal phase-shifting transformer, the imda nce is unchanged when it is referred from one side to the other. (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
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.
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.
Reconsider Problem 3.64 with the change that now Tb includes both a transformer of the same turns ratio as Ta and a regulating transformer with a 4 phase shift. On the base of Ta, the impedance of the two comp onents of Tb is jO.1 per unit. Determine the complex power in per unit transmitted to the load through each transformer. Comment on how the transformers share the real and reactive pors.
Three single-phase, two-winding transformers, each rated 450MVA,20kV/288.7kV, with leakage reactance Xeq=0.10perunit, are connected to form a three-phase bank. The high-voltage windings are connected in Y with a solidly grounded neutral. Draw the per-unit equivalent circuit if the low-voltage windings are connected (a) in with American standard phase shift or (b) in Y with an open neutral. Use the transformer ratings as base quantities. Winding resistances and exciting current are neglected.
A single-phase 50-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down transformer at the load end of a 2400-volt feeder whose series impedance is (1.0+j2.0) ohm. The equivalent series impedance of the transformer is (1.0+j2.5) ohms referred to the high-voltage (primary) side. The transformer is delivering rated load at a 0.8 power factor lagging and at a rated secondary voltage. Neglecting the transformer exciting current, determine (a) the voltage at the transformer primary terminals, (b) the voltage at the sending end of the feeder, and (c) the real and reactive power delivered to the sending end of the feeder.
The leakage reactance of a three-phase, 300-MVA,230Y/23-kV transformer is 0.06 per unit based on its own ratings. The Y winding has a solidly grounded neutral. Draw the per-unit equivalent circuit. Neglect the exciting admittance and assume the American Standard phase shift.
A three-phase transformer is rated 1000MVA,220Y/22kV. The Y-equivalent short-circuit impedance, considered equal to the leakage reactance, measured on the low-voltage side is 0.1. Compute the per-unit reactance of the transformer. In a system in which the base on the high-voltage side of the transformer is 100MVA,230kV what value of the per-unit reactance should be used to represent this transformer?