Loose Leaf for Engineering Circuit Analysis Format: Loose-leaf
9th Edition
ISBN: 9781259989452
Author: Hayt
Publisher: Mcgraw Hill Publishers
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Chapter 12, Problem 41E
To determine
The circumstances in which the delta connected load might be preferred over the star connected load.
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Students have asked these similar questions
Three similar coils, connected in star, take a total
power of 1.5 kW, at a power factor of 0.2, from a
three-phase, 400 V, 50 Hz supply. Calculate: (a) the
resistance and inductance of each coil; (b) the line
currents if one of the coils is short-circuited.
(a) Three 20 µF capacitors are star-connected across
a 400 V, 50 Hz, three-phase, three-wire supply.
Calculate the current in each line. (b) If one of the
capacitors is short-circuited, calculate the line cur
rents. (c) If one of the capacitors is open-circuited,
calculate: the line currents and the p.d. across each
of the other two capacitors.
ANS:
1.525 A; 2.64 A, 2.64 A, 4.57 A; 1.32 A, 1.32 A, 0;
210 V
Explain the advantages of three-phase supply for
distribution purposes.
(b) Assuming the relationship between the line and
phase values of currents and voltages, show that
the active power input to a three-phase balanced
load is √3VI cos φ, where V and I are line quantities.
(c) Three similar inductors, each of resistance 10 Ω
and inductance 0.019 H, are delta-connected to a
three-phase, 400 V, 50 Hz sinusoidal supply. Calcu
late: the value of the line current; the power
factor and the active power input to the circuit.
ANS:
59.5 A, 0.858 lag, 35.5 kW
Chapter 12 Solutions
Loose Leaf for Engineering Circuit Analysis Format: Loose-leaf
Ch. 12.1 - Let and . Find (a) Vad; (b) Vbc; (c) Vcd.Ch. 12.2 - Prob. 2PCh. 12.2 - Modify Fig. 12.9 by adding a 1.5 resistance to...Ch. 12.3 - A balanced three-phase three-wire system has a...Ch. 12.3 - A balanced three-phase three-wire system has a...Ch. 12.3 - Three balanced Y-connected loads are installed on...Ch. 12.4 - Each phase of a balanced three-phase -connected...Ch. 12.4 - Prob. 8PCh. 12.5 - Determine the wattmeter reading in Fig. 12.24,...Ch. 12.5 - Prob. 10P
Ch. 12 - Prob. 1ECh. 12 - Prob. 2ECh. 12 - Prob. 3ECh. 12 - Describe what is meant by a polyphase source,...Ch. 12 - Prob. 5ECh. 12 - Prob. 6ECh. 12 - Prob. 7ECh. 12 - Prob. 8ECh. 12 - Prob. 9ECh. 12 - Prob. 10ECh. 12 - The single-phase three-wire system of Fig. 12.31...Ch. 12 - Prob. 12ECh. 12 - Referring to the balanced load represented in Fig....Ch. 12 - Prob. 14ECh. 12 - Prob. 15ECh. 12 - Consider a simple positive phase sequence,...Ch. 12 - Assume the system shown in Fig. 12.34 is balanced,...Ch. 12 - Repeat Exercise 17 with Rw = 10 , and verify your...Ch. 12 - Prob. 19ECh. 12 - Prob. 20ECh. 12 - Prob. 21ECh. 12 - Prob. 22ECh. 12 - A three-phase system is constructed from a...Ch. 12 - Prob. 24ECh. 12 - Each load in the circuit of Fig. 12.34 is composed...Ch. 12 - Prob. 26ECh. 12 - Prob. 27ECh. 12 - A three-phase load is to be powered by a...Ch. 12 - For the two situations described in Exercise 28,...Ch. 12 - Prob. 30ECh. 12 - Prob. 31ECh. 12 - Prob. 32ECh. 12 - Repeat Exercise 32 if Rw = 1 . Verify your...Ch. 12 - Prob. 34ECh. 12 - Prob. 35ECh. 12 - Prob. 36ECh. 12 - A wattmeter is connected into the circuit of Fig....Ch. 12 - Find the reading of the wattmeter connected in the...Ch. 12 - (a) Find both wattmeter readings in Fig. 12.39 if...Ch. 12 - Circuit values for Fig. 12.40 are , , , , . Find...Ch. 12 - Prob. 41ECh. 12 - Prob. 42ECh. 12 - (a) Is the load represented in Fig. 12.41...Ch. 12 - Prob. 44E
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- not use ai pleasearrow_forwardA three-phase, 400 V, star-connected motor has an output of 50 kW, with an efficiency of 90 per cent and a power factor of 0.85. Calculate the line current. Sketch a phasor diagram showing the voltages and currents. If the motor windings were connected in mesh, what would be the correct voltage of a three phase supply suitable for the motor? ANS: 90.8 A, 240 Varrow_forwardDon't use ai to answer I will report you answerarrow_forward
- Show with the aid of a phasor diagram that for both star- and delta-connected balanced loads, the total active power is given by √3VI cos φ, where V and I are the line values of voltage and current respectively and φ is the angle between phase values of voltage and current. A balanced three-phase load consists of three coils, each of resistance 4 Ω and inductance 0.02 H. Determine the total active power when the coils are (a) star-connected, (b) delta-connected to a 400 V, three phase, 50 Hz supply. ANS:11.56 kW, 34.7 kWarrow_forwardThe load connected to a three-phase supply comprises three similar coils connected in star. The line currents are 25 A and the apparent and active power inputs are 20 kVA and 11 kW respectively. Find the line and phase voltages, reactive power input and the resistance and reactance of each coil. If the coils are now con nected in delta to the same three-phase supply, calculate the line currents and the active power taken. ANS : 462 V, 267 V, 16.7 kvar, 5.87 Ω, 8.92 Ω; 75 A, 33 kWarrow_forwardA three-phase delta-connected load, each phase of which has an inductive reactance of 40 Ω and a resistance of 25 Ω, is fed from the secondary of a three-phase star-connected transformer which has a phase voltage of 230 V. Draw the circuit diagram of the system and calculate: (a) the current in each phase of the load; (b) the p.d. across each phase of the load; (c) the current in the transformer secondary windings; the total active power taken from the supply and its power factor.arrow_forward
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