3. A 3-0 star-connected alternator is rated at 1600 kVA, 13,500 V. The armature effecti resistance and synchronous reactance are 1.5 2 and 30 2 respectively per phase. Calcula the percentage regulation for a load of 1280 kW at power factors of (a) 0.8 leading ar (b)0.8 lagging. 4. Determine the voltage regulation of a 2,000-V, 1-phase alternator givinga current of 100 A 0.8 p.f. leading from the test results. Full-load current of 100 A is produced on short-circuitI a field excitation of 2.5 A. An e.m.f. of 500 V is produced on open-circuit by the san excitation. The armature resistance is 0.8 Q. Draw the vector diagram. [(a) –11.8% (b) 18.6% |- 8.9%

3. A 3-0 star-connected alternator is rated at 1600 kVA, 13,500 V. The armature effecti resistance and synchronous reactance are 1.5 2 and 30 2 respectively per phase. Calcula the percentage regulation for a load of 1280 kW at power factors of (a) 0.8 leading ar (b)0.8 lagging. 4. Determine the voltage regulation of a 2,000-V, 1-phase alternator givinga current of 100 A 0.8 p.f. leading from the test results. Full-load current of 100 A is produced on short-circuitI a field excitation of 2.5 A. An e.m.f. of 500 V is produced on open-circuit by the san excitation. The armature resistance is 0.8 Q. Draw the vector diagram. [(a) –11.8% (b) 18.6% |- 8.9%

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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A three-phase alternator of 4 poles and 60 HZ, connected in star of 100 KVA and 1100 volts is tested for OCC, SCC and winding resistance, giving the following data: Based on the above data, obtain: a) - The equivalent circuit per phase of the alternator b) - Operating speed c) - If it is synchronized with a power system whose frequency is 60 Hz and the alternator has a Sp=5 kW/Hz and its speed at the moment of synchronization is 1860 rpm, what power will it deliver? d) - What will be your internal voltage generated if you feed a load with forward PF of 0.9 and you are at 80% of your load? e) - For the case of item d), what is the reactive power delivered or consumed?
A 50 kVA, 550 volt single phase alternator draws a field current 10A at rated load with the same field current. The open circuit emf and short circuit current are 300 V and 150 A. the ohmic resistance of the armature between terminals is 0.18 ohm. The ratio of effective to ohmic resistance maybe taken as 1.5 . Determine the regulation at 0.8 power factor lagging.
A 500-V, 50-kVA, single-phase alternator has an effective resistance of 0.2 Ω. A field current of 10A produces an armature current of 200A on short-circuit and emf of 450V on open circuit. Calculate (a) the synchronous impedance and reactance and (b) the full-load regulation with 0.8 p.f. lagging.
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A 1200 kVA, 6600 volts, 3-phase Y connected alternator, has an effective resistance of 0.4 ohms and a synchronous reactance of 6 ohms per phase. It delivers full load current at 0.8 lagging power factor at rated voltage. What will be the generated voltage if the power factor is change to 0.8 leading. Solve for the % voltage regulation both for 0.8 lagging and 0.8 leading power factors.
A 3-Phase 10Kva, 400 V, 50Hz star connected alternator supplies a rated load at 0.8 power factor lagging. If the armature resistance per phase is 0.5Ჲ and the synchronous reactance is 10Ჲ, using the e.m.f method, estimate the alternator’s voltage regulation
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A single-phase alternator connected to 6,600-V bus-bars has a synchronous impedance of 10Ω and a resistance of 1 Ω. If its excitation is such that on open circuit the p.d. would be 5000 V, calculate the maximum load the machine can supply to the external circuit before dropping out of step and the corresponding armature current and p.f. [2864 kW, 787 A, 0.551]
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