Basic Electrical Engineering syllabus

 

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Code :9A02306

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II B.Tech I semester (R09) Regular Examinations, November 2010 BASIC ELECTRICAL ENGINEERING (Computer Science & Systems Engineering, Information Technology, Computer Science & Engineering)

Time: 3 hours

Max Marks: 70 Answer any FIVE questions All questions carry equal marks      

1. (a) Defin Definee and expla explain in resi resistan stance, ce, ind inducta uctance, nce, an and d capaci capacitanc tance. e. (b) Two resistances of 1.5Ω and 3.5Ω are connected in parallel and this parallel combination is connected in series with a resistance of 1 .95Ω . Fin Find d the equiv equivale alent nt resi resistan stance ce of the circuit. What current will it draw if connected to a 30V supply. 2. (a) Stat Statee and eexpl xplain ain ssuperpos uperpositi ition on th theore eorem. m. (b)

Find the equivalent resistance between C and D. 3. Show that peak factor of a sinu sinusoidal soidal curren currentt wav wavee form is 1.414. 4. (a) Expl Explain ain the con constru structi ctional onal de detail tailss of singl singlee phase tra transf nsforme ormer. r. (b) A single phase transformer working at unity power factor has an efficiency of 90% at both half load and at full load of 600W. Determine the efficiency at 80% of full load. 5. (a) Deri Derive ve the eemf mf eq equati uation on of DC ge genera nerator. tor. (b) A 4 - pole DC shunt generator with lap - connected armature supplies a load of 100A at 200V. The armature resistance is 0 .1Ω and the sh shun untt fiel field d res resis istan tance ce is 80Ω . Find Find the total armature current and emf generated. 6. (a) Expl Explain ain tthe he pri princi nciple ple ooff opera operation tion ooff DC Mo Motor. tor. (b) A 100V series motor takes 45A when running at 750 rpm. Its armature resistance is 0 .22Ω , while the series field resistance is 0.13Ω . Iron and friction losses amount to 750W. Find the shaft power. 7. Explai Explain n the principle of operation of 3 - phase induction motor in detail. detail. 8. Explai Explain np permanen ermanentt magnetic moving coil instrum instruments ents in detail with a neat diagram.      

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Code :9A02306

2

II B.Tech I semester (R09) Regular Examinations, November 2010 BASIC ELECTRICAL ELECTRICAL ENGINEERING ENGINEERING (Computer Science & Systems Engineering, Information Technology, Computer Science & Engineering)

Time: 3 hours

Max Marks: 70 Answer any FIVE questions All questions carry equal marks 

1. (a) Define and explain explain basic basic ccircui ircuitt component components. s. (b)

If the total power disipated in a network shown is 16W, find the value of R and the total current. 2. (a) State and explain explain Thevenin’s Thevenin’s theorem. theorem. (b)

Determine the current delivered by the source. 3. (a) Show that that power dissipat dissipated ed by a pure inductive inductive circuit excited excited by a sinusoidal sinusoidal source source is zero. (b) A pure capacitance capacitance   C   = 10µF   passes passes a curren currentt i = 10sin 10sin 2000t amperes. amperes. Find Find the voltag voltagee across across the element. 4. Explain Explain the tests tests to be conducted to determine determine copper and iron losses with neat circuit circuit diagram. 5. (a) Explain Explain the principle principle of operation operation of DC DC generator generator.. (b) A six pole, lap-w lap-woun ound d armatu armature re has 840 conduct conductors ors and flux per pole of 0.018Wb. 0.018Wb. Calcul Calculate ate the emf  generated, when the machine is running at 600 rpm. 6. (a) What is the the significance significance of Swinbu Swinburnis rnis Test? Test? Explain with a neat neat diagra diagram. m. (b) A 220V DC shunt motor motor takes a total current current of 100A and runs at 750 rpm. The resistance resistance of armature armature winding and of shunt field winding is 0 .1Ω and 40Ω respectively respectively.. Find the torque torque developed developed by armature. armature. 7. (a) Explain Explain with the help of suitable suitable diagram, diagram, how how a rotating rotating magnetic magnetic field is produced produced in a 3 - phase induction induction motor. (b) A 12 - pole 3 - phase induction induction motor motor runs at 485 rpm on a 50 Hz supply. supply. Calculate Calculate slip. slip. 8. Explain Explain the principle principle and the operation of moving moving iron attracti attraction on type instrumen instruments ts with neat diagram. diagram. 

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Code :9A02306

3

II B.Tech I semester (R09) Regular Examinations, November 2010 BASIC ELECTRICAL ENGINEERING (Computer Science & Systems Engineering, Information Technology, Computer Science & Engineering)

Time: 3 hours

Max Marks: 70 Answer any FIVE questions All questions carry equal marks 

1. (a) Defin Definee and exp explai lain n Ki Kirch rchhoff’s hoff’s llaw aw.. (b) Three resistors of 5Ω, 10Ω, 15Ω are joi joined ned in para paralle llel. l. If the curr curren entt in 10Ω res resisto istorr is 3A, what is the current in other resistors and the total current? 2. (a) Expl Explain ain tthe he pas passiv sivee ele elemen ments ts in d detai etail. l. (b) By using Thevenins theorem find the current through 5Ω resistor.

3. Show that form factor of a sinusoida sinusoidall current is 1.11. 4. (a) Expl Explain ain th thee princ principl iplee of operati operation on of a singl singlee phase tr trans ansform former. er. (b) A 3300/220V, 30KVA, single phase transformer takes a no load current of 1.5A when the low voltage winding is open. The Iron loss component is 0.4A. Find i. No load inp input ut powe power. r. ii. Magnetis Magnetising ing component component.. iii. Po Power wer factor of no load current. 5. Expl Explain ain the types of DC Gener Generator ator in detail detail.. 6. (a) Expl Explain ain tthe he lo losses sses that occ occur ur in a D DC C Mac Machin hine. e. (b) A 500V DC shunt motor takes 4A on no load. The armature resistance including that of  brushes is 0.2Ω and the field current is 1.0A. Estimate the output and efficiency when the input current is 20A. 7. (a) Defin Definee and exp explai lain n sli slip p of 3-p 3-phase hase iinduc nductio tion n moto motor. r. (b) Calculate the synchronous speed, slip and rotor frequency of a 3-phase 50Hz, 4-pole induction motor running at 1440 rpm. 8. (a) Mak Makee a comp comparis arison on betw between een spri spring ng cont control rol and gra gravit vity y contr control. ol. (b) A moving - coil instrument gives a full scale deflection, when the current is 35mA and its resistan resi stance ce is 20Ω. Cal Calcul culate ate the value of the sh shun untt to be conn connecte ected d in parall parallel el with the meter to enable it to be used as an ammeter for measuring currents upto 45A. 

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Code :9A02306

4

II B.Tech I semester (R09) Regular Examinations, November 2010 BASIC ELECTRICAL ENGINEERING (Computer Science & Systems Engineering, Information Technology, Computer Science & Engineering)

Time: 3 hours

Max Marks: 70 Answer any FIVE questions All questions carry equal marks 

1. (a (a)) Defi Define ne an and d ex expl plai ain n Oh Ohm’ m’ss La Law. w.

(b) the For F or network the circuit shown, is 1.5 A. calculate the value of resistance r, when the total current taken by 2. (a (a)) Exp Expla lain in th thee ty types pes of so sourc urces es in de detai taill .

(b) By using By  using the superposition theorem find the current through 8 Ω resistor. 3. (a) Deri Derive ve the exp express ression ion for R.M. R.M.S S val value ue of a sin sinusoi usoidal dal curr curren entt wav wavee form. (b) Calculate the current, power and power factor of the given circuit.

4. Define efficien efficiency cy and regulatio regulation n of transformer. Explai Explain n the tests to be conducted to predeterpredetermine the efficiency and regulation with neat diagrams. 5. (a (a)) Wha Whatt is the si sign gnifi ifican cance ce of open circ circui uitt ch chara aracte cteris risti tics cs?? Ho How w th these ese cha charac racter teris isti tics cs ar aree determined experimentally. (b) A 4-pole DC generator has 378 wave wound conductors in its armature. If the fluxes per pole is 0.02 wb and the generator runs at 1000 rpm. Calculate the induced emf. 6. (a) Deri Derive ve tthe he ex expres pressio sion n for to torqu rquee of a DC motor motor.. www.jntuworld.com

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Code :9A023 :9A02306 06

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(b) A DC series motor having a resistance of 1Ω between terminals, runs at a speed of 800 rpm at 200v with a current of 15A. Find the speed at which it will run when connected in series with a 5Ω resistance taking the same current at the same supply voltage. 7. (a) Deri Derive ve the relat relation ionshi ship pb bet etwe ween en the frequen frequency cy of the roto rotorr induce induced d emf and the suppl supply y frequency of the stator. (b) A 6-pole induction motor is fed by a 3-phase 50Hz supply and running with a full load slip of 3%. Find the full load speed of the induction motor and also the frequency of the rotor emf. 8. (a) Expl Explain ain the prin princip ciple le and operati operation on of movi moving ng iron repu repulsi lsion on type inst instrume ruments nts.. (b) A meter movement with full-scale deflection current of 80 µ   A and internal resistance of  50Ω is required to measure a maximum curren currentt of 25mA. Determ Determine ine the shunt resist resistance ance needed. 

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