Q 4/ A 3000 kVA, 3-phase, star-connected, 50 Hz, 2800 V alternator has resistance 0.120. A field current of 60 A produces a short circuit equal to full load current of 618 A in each line. The same field current produces an emf of 800 V on open circuit. Determine : 1_Synchronous Impedance. . 2_Synchronous Reactance.. . 3_Phase Current.. .Amp 4_The excitation voltage of the machine ...V. at 0.8 power factor lagging * 5_The full load regulation at 0.8 power factor lagging. e 9:12 älues

Q 4/ A 3000 kVA, 3-phase, star-connected, 50 Hz, 2800 V alternator has resistance 0.120. A field current of 60 A produces a short circuit equal to full load current of 618 A in each line. The same field current produces an emf of 800 V on open circuit. Determine : 1_Synchronous Impedance. . 2_Synchronous Reactance.. . 3_Phase Current.. .Amp 4_The excitation voltage of the machine ...V. at 0.8 power factor lagging * 5_The full load regulation at 0.8 power factor lagging. e 9:12 älues

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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Similar questions

A three-phase 3300V. 50 Hz star-connected alternator has an effective resistance of 0.5 ohm/phase. A field current to of 30A produces full-load current of 180A on short- circit and a line to line emf of 1000V on open circit Determine(i) the power angle of the alternator when it delivers full-load at 0.8p.f(lag) (ii)the SCR of the alternator D
6. A 3-phase, star-connected alternator has a resistance of 0.52/phase and a synchronous reactance of 52/phase. It is excited to give 6600 V (line) on open circuit. Determine the terminal voltage and voltage regulation on full-load current of 130 A when the load p.f. is (a) 0.8 lagging (b) 0.6 leading. (Ans. (a) 3340 V (phase value); 14.1% (b) 4260 V (phase value); - 10.6%)
The p.u. impedance value of an alternator corresponding to base values of 13.2 kV and 30 MVA is 0.2 p.u. Then the p.u. impedance value of an alternator for the new base values of 13.8 kV and 50 MVA is......
q6/ Complete the blank In AC-DC power transmission system, ............................................. is used to convert the DC supply into AC supply.
A synchronous generator with a synchronous reactance of 1.15 p.u. is connected to an infinite bus whose voltage is one p.u. through an equivalent reactance of 0.15 p.u. The maximum permissible active power output is 1.2 p.u.A. Compute the excitation voltage E.B. The power output is gradually reduced to 0.7 p.u. with fixed field excitation. Find the new current and power angle δ.
The step down DC chopper uses DC source voltage V(dc) = 200 V and resistive load impedance of 10 ohm. The duty cycle is 0.4 the voltage drop across the switch may be taken as zero, Calculate : (a) Average and RMS value of output voltage. (b) Average and RMS value of output current.
A 3-phase star connected, 1500 kVA, 13 kV alternator has an armature resistance of 0.9 ohm and a synchronous reactance of 8.0 ohms. When carrying rated load voltage, calculate the generated voltage per phase at loads of I.) Unity P.F. ii.) 0.8 lagging P.F. iii.) 0.8 leading P.F. iv.) calculate the voltage regulation for each load and determine best regulation.
A three phase star connected, 1500 kVA, 13 kV alternator has an armature resistance of 0.9 ohm and a synchronous reactance of 8.0 ohms. When carrying rated load voltage, calculate the generated voltage per phase at loads of a. Unity P.F. b. 0.8 lagging P.F. c. 0.8 leading P.F. d. Calculate the voltage regulation for each loads and determine best regulation.
A 3Ø, Y-connected alternator is rated at 1,600KVA, 13.5KVv. The armature effective AC resistance per phase is 1.50. The percentage regulation for a load of 1,280kW at unity power factor is 3.5%. Determine: (a) synchronous reactance of the alternator (b) %VR at full-load 0.8pf leading (c) What is the effect on %VR value if taken at half-load lagging pf? Justify and explain briefly your answer on one(1) sentence.
A 200 – ohm resistor, 130 millihenry inductor, and a 66 microfarad are placed in parallel across a 120 – V, 60 – Hz AC line. Calculate the following: a.) RESISTOR CURRENT b.) INDUCTOR CURRENT c.) CAPACITOR CURRENT d.) TOTAL CURRENT e.) PHASE ANGLE f.) TOTAL IMPEDANCE DRAW THE PHASOR DIAGRAM IF POSSIBLE AND ROUND OFF TO FOUR DECIMAL PLACES.
Discussion:- 1. What do you understand by "armature- reaction"? Discuss the effect of armature reaction in an alternator when it is loaded with resistive, inductive and capacitive loads. 2. Give the value of voltage regulation for different power factors at full load current and interpret their values.
As seen in the figure, three generators of 800 kW, 900 kW and 1000 kW are connected in parallel. It generators feed 380 kW load. Frequency-active power graphs of generators are shown as given. According to this; a. Calculate the operating frequency for the situation given in the question.b. Calculate the power transferred by the generators to the load.c. A three-phase asynchronous load of 800 kW and 600 kVA with a reverse power coefficient of 0.78 is installed in the system. engine is connected. The new operating frequency of the system and the active power of the alternators. calculate.d. Do you think the generators in this system are suitable for parallel connection as in the figure?