MindTap Engineering, 1 term (6 months) Printed Access Card for Glover/Overbye/Sarma's Power System Analysis and Design, 6th
6th Edition
ISBN: 9781305636323
Author: Glover, J. Duncan, Overbye, Thomas, Sarma, Mulukutla S.
Publisher: Cengage Learning
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Textbook Question
Chapter 3, Problem 3.9MCQ
Match the following:
(i) Hysteresis loss (a) Can be redud by constructing the core with laminated sheets of alloy steel
(ii) Eddy current loss (b) Can be reduced by the use of special high grades of alloy stl as core material.
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Chapter 3 Solutions
MindTap Engineering, 1 term (6 months) Printed Access Card for Glover/Overbye/Sarma's Power System Analysis and Design, 6th
Ch. 3 - The Ohms law for the magnetic circuit states that...Ch. 3 - For an ideal transformer, the efficiency is (a) 0...Ch. 3 - For an ideal 2-winding transformer, the...Ch. 3 - An ideal transformer has no real or reactive power...Ch. 3 - For an ideal 2-winding transformer, an impedance...Ch. 3 - Consider Figure 3.4. For an ideal phase-shifting...Ch. 3 - Consider Figure 3.5. Match the following, those on...Ch. 3 - The units of admittance, conductance, and...Ch. 3 - Match the following: (i) Hysteresis loss (a) Can...Ch. 3 - For large power transformers rated more than 500...
Ch. 3 - For a short-circuit test on a 2-winding...Ch. 3 - The per-unit quantity is always dimensionless. (a)...Ch. 3 - Consider the adopted per-unit system for the...Ch. 3 - The ideal transformer windings are eliminated from...Ch. 3 - To convert a per-unit impedance from old to new...Ch. 3 - In developing per-unit circuits of systems such as...Ch. 3 - Prob. 3.17MCQCh. 3 - Prob. 3.18MCQCh. 3 - With the American Standard notation, in either a...Ch. 3 - Prob. 3.20MCQCh. 3 - In order to avoid difficulties with third-harmonic...Ch. 3 - Does an open connection permit balanced...Ch. 3 - Does an open- operation, the kVA rating compared...Ch. 3 - It is stated that (i) balanced three-phase...Ch. 3 - In developing per-unit equivalent circuits for...Ch. 3 - In per-unit equivalent circuits of practical...Ch. 3 - Prob. 3.27MCQCh. 3 - Prob. 3.28MCQCh. 3 - For developing per-unit equivalent circuits of...Ch. 3 - Prob. 3.30MCQCh. 3 - Prob. 3.31MCQCh. 3 - Prob. 3.32MCQCh. 3 - The direct electrical connection of the windings...Ch. 3 - Consider Figure 3.25 of the text for a transformer...Ch. 3 - (a) An ideal single-phase two-winding transformer...Ch. 3 - An ideal transformer with N1=1000andN2=250 is...Ch. 3 - Consider an ideal transformer with...Ch. 3 - A single-phase 100-kVA,2400/240-volt,60-Hz...Ch. 3 - Prob. 3.5PCh. 3 - Prob. 3.6PCh. 3 - Consider a source of voltage v(t)=102sin(2t)V,...Ch. 3 - Prob. 3.8PCh. 3 - Prob. 3.9PCh. 3 - A single-phase step-down transformer is rated...Ch. 3 - For the transformer in Problem 3.10. The...Ch. 3 - Prob. 3.12PCh. 3 - A single-phase 50-kVA,2400/240-volt,60-Hz...Ch. 3 - A single-phase 50-kVA,2400/240-volt,60-Hz...Ch. 3 - Rework Problem 3.14 if the transformer is...Ch. 3 - A single-phase, 50-kVA,2400/240-V,60-Hz...Ch. 3 - The transformer of Problem 3.16 is supplying a...Ch. 3 - Using the transformer ratings as base quantities,...Ch. 3 - Using the transformer ratings as base quantities....Ch. 3 - Using base values of 20 kVA and 115 volts in zone...Ch. 3 - Prob. 3.21PCh. 3 - A balanced Y-connected voltage source with...Ch. 3 - Figure 3.32 shows the oneline diagram of a...Ch. 3 - For Problem 3.18, the motor operates at full load,...Ch. 3 - Consider a single-phase electric system shown in...Ch. 3 - A bank of three single-phase transformers, each...Ch. 3 - A three-phase transformer is rated...Ch. 3 - For the system shown in Figure 3.34. draw an...Ch. 3 - Consider three ideal single-phase transformers...Ch. 3 - Reconsider Problem 3.29. If Va,VbandVc are a...Ch. 3 - Prob. 3.31PCh. 3 - Determine the positive- and negative-sequence...Ch. 3 - Consider the three single-phase two-winding...Ch. 3 - Three single-phase, two-winding transformers, each...Ch. 3 - Consider a bank of this single-phase two-winding...Ch. 3 - Three single-phase two-winding transformers, each...Ch. 3 - Three single-phase two-winding transformers, each...Ch. 3 - Consider a three-phase generator rated...Ch. 3 - The leakage reactance of a three-phase,...Ch. 3 - Prob. 3.40PCh. 3 - Consider the single-line diagram of the power...Ch. 3 - For the power system in Problem 3.41, the...Ch. 3 - Three single-phase transformers, each rated...Ch. 3 - A 130-MVA,13.2-kV three-phase generator, which has...Ch. 3 - Figure 3.39 shows a oneline diagram of a system in...Ch. 3 - The motors M1andM2 of Problem 3.45 have inputs of...Ch. 3 - Consider the oneline diagram shown in Figure 3.40....Ch. 3 - With the same transformer banks as in Problem...Ch. 3 - Consider the single-Line diagram of a power system...Ch. 3 - A single-phase three-winding transformer has the...Ch. 3 - The ratings of a three-phase three-winding...Ch. 3 - Prob. 3.52PCh. 3 - The ratings of a three-phase, three-winding...Ch. 3 - An infinite bus, which is a constant voltage...Ch. 3 - A single-phase l0-kVA,2300/230-volt,60-Hz...Ch. 3 - Three single-phase two-winding transformers, each...Ch. 3 - A two-winding single-phase transformer rated...Ch. 3 - A single-phase two-winding transformer rated...Ch. 3 - Prob. 3.59PCh. 3 - PowerWorid Simulator case Problem 3_60 duplicates...Ch. 3 - Rework Example 3.12 for a+10 tap, providing a 10...Ch. 3 - A 23/230-kV step-up transformer feeds a...Ch. 3 - The per-unit equivalent circuit of two...Ch. 3 - Reconsider Problem 3.64 with the change that now...Ch. 3 - What are the advantages of correctly specifying a...Ch. 3 - Why is it important to reduce the moisture within...Ch. 3 - What should be the focus of transformer preventive...
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- a core type transforem is constructed with 0.014-in. thick laminations having a uniform width of 2.75 in. If the maximum flux and flux density are, respectively, 6.2 X 10' maxwells and 8.2 X 10 maxwells per square inch and the air spaces between laminations occupy 8 per cent of the stacked core, calculate the number of laminations in the transformer. Iarrow_forward(9) The hysteresis losses in electrical machines reduced. a- By core lamination. b- By core isolation. c- By choosing another type of iron. (10) The eddy current losses in electrical machines reduced. d- By core lamination. e- By core isolation. f- By choosing another type of iron.arrow_forwardA transformer has primary and secondary turns of 1250 and 125 respectively. It has core cross-sectionof 36 cm2 and its rms flux density is to be limited to 1.4 T (to prevent core saturation). Whatmaximum 50 Hz voltage can be applied on the primary side and the corresponding open-circuitsecondary voltage?The core has a mean length of 150 cm and its relative permeability can be assumed to be 8000. Whatwould be the rms exciting current when the transformer’s primary winding is excited at a voltage ascalculated above? Also calculate the magnetizing susceptance as seen from primary and secondarysides.If the transformer were to be excited at 60 Hz, 1. What should be the maximum primary voltage for thecore flux density limit not to be exceeded? 2. What would be the magnetizing susceptance as seen oneach side in this case?arrow_forward
- The core of a transformer operating at 50 Hz has an eddy current loss of 100 W/m3 and the corelaminations have a thickness of 0.50 mm. The core is redesigned so as to operate with the same eddycurrent loss but at a different voltage and at a frequency of 250 Hz. Assuming that at the new voltage themaximum flux density is one-third of its original value and the resistivity of the core remains unaltered,determine the necessary new thickness of the laminations. Clear and detailed solution.arrow_forward5 The core of an electro-magnetic structure is Laminated in order to: reduce the Stacking Factor reduced the Hysteresis Loss of the core reduce the Eddy-Current Loss of the core improve the Input Power Factor of the structure.arrow_forwardWhich of the ff given below is the eddy current loss not proportional to? Square of the frequency Square of the flux density Square of the load current of the laminated core Square of the thicknessarrow_forward
- 2. What is the material commonly used for construction of transformer core? Draw the B - H curve for this material?arrow_forwardExplain why, when steel is subjected to alternating magnetization energy, losses occur due to bothhysteresis and eddy currents. The core loss in a transformer core at normal flux density was measured atfrequencies of 40 Hz and 50 Hz, the results being 40 W and 52.5 W respectively. Calculate, at a frequencyof 50 Hz, (a) the hysteresis loss and (b) the eddy current loss. Clear and detailed solution.arrow_forwardA small single-phase 60 Hz transformer has 10.2 W at no load. The core has a volume of 750 cm3. The maximum flux density is 10,000 G and the hysteresis constant of the core is 0.0005. Using the Steinmetz law on hysteresis loss, find the eddy current loss.arrow_forward
- the armature mmf can be -2 reduced by reluctance of the magnetic the circuit in the region of the pole .tip a) Increasing, O b) decreasing O c) don't put Oarrow_forwardIn transformer, the eddy current loss can be minimized by O using thin size copper conductors O using magnetic material with low permeability laminating the core O using magnetic material with high permeabilityarrow_forward3. If we use in transformer core (i) solid magnetic material, (ii) nonmagnetic material, comment on the consequences?arrow_forward
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