unit i - diet.edu.indiet.edu.in/questionbanks/iii btech i sem/iii-eee-b-i-sem.pdf · dadi institute...

DADI INSTITUTE OF ENGINEERING & TECHNOLOGY (Approved by A.I.C.T.E., New Delhi & Affiliated to JNTUK, Kakinada)

An ISO 9001:2008, ISO 14001:2004 & OHSAS 18001:2007 Certified Institute.

NH-5, Anakapalle – 531002, Visakhapatnam, A.P.

Phone: 08924-221111 / 221122/9963981111, www.diet.edu.in, E-mail: [email protected]

QUESTION BANK

Course : B.Tech. Branch : EEE Year/Semester : III/I Academic Year : 2017-18

Faculty Name : K.VIJAY KUMAR Subject : Electrical Measurements Control Admitted Batch : 2014 Regulation: R13

UNIT – I

1) a) Explain the essential features of Indicating Instruments.

b) Explain about Spring control and gravity control controlling devices.

c) Explain the significance of Eddy current damping in an indicating Instrument.

2) a) Derive the Torque equation for Moving iron Instruments. b) Explain the various methods of providing damping torque in an indicating

instrument.

3) a) Explain the construction and working of Repulsion type Moving iron Instruments. b) Explain the following terms with respect to Instrument transformers:- i) Actual Ratio ii) Nominal ratio iii) Ratio correction factor iv) Burden of an instrument transformer. 4) a) Explain the construction and working of a Permanent magnet moving coil meter.

b) Compare between Current transformer and Potential transformer.

5) a) a) Derive the actual ratio of a Current transformer from its equivalent circuit and Phasor diagram. b) Derive the equation for deflection of a Dynamometer type of instruments which

can be used for both DC and AC.

UNIT – II 1) a) Explain with a neat circuit of Dynamometer type Wattmeter and derive the

equation for deflection. b) List the various types of errors in dynamometer type Wattmeter’s.

2) a) Explain the working of Induction type single phase Energy meter with a neat diagram. b) A 50 A, 230V meter on full load test makes 61 revolutions in 37 seconds. If the normal disc speed is 520 revolutions per KWH, find the percentage error.

3) a) Explain how a power measurement range can be extended with a wattmeter in conjunction with an instrument transformer. b) A single phase KWh meter makes 500 revolutions per KWh. It is found, on testing, as making 40 revolutions in 58 seconds at 5 KW full load. Find out the percentage





error.

4) a) Derive the actual ratio of a Current transformer from its equivalent circuit and Phasor diagram.

b) Why secondary of current transformer should never be open when the Primary winding is energized.

5) A)Define LPF and UPF wattmeter’s and give their significance. B) What do you mean by Creeping error in Induction Energy meter and how it can

be adjusted? C) What do you understand by Phantom or Fictitious loading in energy meters and why is it necessary?

UNIT – III

1) a) List out the limitations of AC potentiometers.

b) Explain the procedure for standardizing the potentiometer.

c) Explain the significance of a Potentiometer.

d) What are the applications of self balancing Potentiometers?

2) a) How does an AC potentiometer different from a DC Potentiometer. b) Explain how the calibration of Voltmeter and Wattmeter can be done using a DC Potentiometer.

3.a) Explain the working of Crompton Potentiometer with a neat diagram.

b) How the unknown emf is measured using Drysdale – Tinsley A.C. Potentiometer?

4) a)Explain how calibration of Voltmeter and Wattmeter can be done using a DC Potentiometer. b) List the basic requirements of AC potentiometers.

5) a) Explain the working of Gall Co-ordinate type Potentiometer with a neat diagram. b) Explain how the Voltage and power can be measured using a dc Potentiometer.

UNIT – IV 1) a) From the point of measurement, how can resistances be classified.

b) Discuss the common sources of error in AC bridges. How are they eliminated?

c) How are detectors classified? Explain each one of them briefly.

d) State the applications of Wein Bridge.

2) a) Explain any one method for the measurement of high resistance and explain its advantages over other methods.

b) Deduce the general equation or condition for bridge balance in AC Circuits.

3) a) Explain the procedure of measuring a low resistance with the help of Kelvin’s





double bridge. Derive the necessary relation for finding the unknown resistance

under balanced condition of the bridge.

b) Explain the working of Carey – Foster slide wire bridge with neat circuit diagram.

4) a) Explain with a neat diagram for the measurement of Inductance using Hay bridge and also derive the relation for inductance under balanced condition using a neat

phasor diagram.

b) Explain the importance of Wagner’s earthing device.

5) a) Explain how the inductance can be measured by using Maxwell bridge with a neat Diagram.

b) A balanced 5 KHz bridge has the following configuration: Arm AB : R1 = 4000_ in parallel with C1 = 0.063μF BC : R2 = 2500_ in series with C2 = 0.63μF CD : the unknown R and C DA : Pure capacitance C4 = 0.305μF Calculate the unknown R and C. Draw the phasor diagram of the above bridge under balanced condition.

UNIT – V

1) a) How are magnetic materials classified?

b) Explain the AC bridge method for measurement of iron losses in ferromagnetic materials.

2) a) Explain the AC Potentiometer method for measurement of iron losses in ferromagnetic materials.

b) Define the following terms related to magnetic materials: i) Magnetic field strength ii) Curie temperature.

3) a) Explain the operation of Ballistic Galvanometer with a neat diagram. b) c) List the precautions needed to be taken in Magnetic testing.

4) a) Give the merits and demerits of ring and bar specimens that are commonly used in magnetic testing of materials. b) Explain the method for finding out the B-H curve of a magnetic materials using step by step method. 5) a) Explain the determination of Hysteresis loop by method of reversals using a neat diagram. b) Explain how magnetizing and loss components of no load current of a transformer be determined by using an A.C. Potentiometer.





UNIT – VI 1) a) Explain the working of Dual slope Integrating type Digital Voltmeter with a neat

schematic diagram.

b) Explain the basic scheme of Digital multimeter along with its advantages.

2) a) Explain the working of Digital frequency meter with a neat block diagram.

b) Explain the basic block diagram of a Digital voltmeter

3) a) Define resolution and Sensitivity of Digital voltmeter.

b) Explain the working of Linear Ramp type Digital voltmeter with a neat schematic.

4) a) Explain the working of Successive Approximation type Digital Voltmeter with a neat diagram.

b) List out the advantages of Digital Voltmeters.

5) a) List the general specifications of Digital Voltmeters.

B) Explain the working of Digital Tachometer with a neat block diagram.





Faculty Name : Mrs. Athira Subject : Intellectual Property rights & Patents

Course :B.Tech. Branch : EEE Year:III Semester :I

UNIT-1 : Introduction to Intellectual Property Law

1. a) What is intellectual property? [4M]

b) What are the various types of Intellectual Property rights? [6M]

2. a) What is the role of Intellectual Property Appellate Board? [4M]

b) Give an account of the development of IP law in India. [6M]

3. a) What are the innovation and inventions of Trade related IPR ? [6M]

b) Explain about the infringement regulatory process [4M]

4. a) “Intellectual Property rights have an in-built sunset”- Explain. [4M]

b) Explain briefly about four important intellectual property rights. [8M]

5. a) Write about “World intellectual property Organization” and its contribution to the

growth of the intellectual property law globally.[8M]

b) What is Geographical Indication? [3M]

6. a) What is misuse of IP rights? What are its remedies? [4M]

b) List out various regulatory authorities under the IP laws in India. [4M]

UNIT-2 : COPYRIGHTS

1. a. Explain the principles of Copyrights.[5M]

b. What are the works in which copyright exist? [3M]

2. a. Write an essay on moral rights of an author under the copyright Act.[8M]

b. Write about the copyright ownership Transfer and duration. .[5M]

3. a. How the copyright in a work is licensed? [8M]

b. Explain Right of distribution and performers w.r.t copyrights.[5M]

4. a. What is originality under copyright law? What are the tests laid down for

determining infringement of copyright in a computer program? [8M]

b. What are the exceptions to the copyright infringement? [8M]

5. a. What is the method of assigning copyright in a work? [8M]

b. Explain originality in copyright works. [4M]

6. a. What is „fair use‟ under the copyright law? [4M]

b. Write about the Semiconductor Chip Protection Act[6M]





UNIT-3 :PATENT

1. a) What are the rights of a patent holder? And, Explain the process patent and product

patent. [6M]

b) Explain the procedure for obtaining a patent for an invention. [6M]

2. a) Explain the concept of „ever greening of patents‟. [5M]

b) What are not patentable subject matters? And Explain „provisional

specification‟.[5M]

3. a) Explain the importance of priority date under patent law and what are the rights of a

patentee? What are the limitations to it? [5M]

b) Explain the procedure of obtaining patent for an invention. [8M]

4. a) What is „patent addition‟ under the Patents Act? [4M]

b) On what grounds a patent can be revoked under the Patents Act? [6M]

5. a) What are the components of a complete specification under the Patents Act?[5M]

b) What is the purpose of compulsory license under the patent law? [5M]

6. a) Whether mathematical methods be patented? [5M]

b) Explain about Patent cooperation treaty. [5M]

UNIT-4 :TRADMARK

1. a. What is a trademark?[4M]

b. Explain the function of a Trade Mark or service mark? [6M]

2. a. Explain the conditions for registration of a trade mark and the procedure for

registration of trademark.[8M]

b. When a trademark owner‟s right to his trademark is said to be infringed? [8M]

3. a. Explain the concept of passing off and the infringement of trademark.[8M]

b. Explain the concept of dilution of trademark. 6[M]

4. a. What are the qualities of an ideal trademark?[8M]

b. What is false trade description under trade mark law? [3M]

5. a. Explain the process of Trade Mark maintenance.[6M]

b. Write about the Trade Mark Transfer rights[6M]

6. a. Write about the Trade marks Litigations[6M]

b. Discuss about the Trade Mark Law Globally[6M]

UNIT-5 :TRADE SECRET





1. a Explain the trade secret. What are the rights of a owner of trade secrets?[5M]

b. Explain the process of Trade Secrets[5M]

2. a. What are the physical securities for the Trade Secret[5M]

b. Explain about the Employee Access Limitations in Trade Secret [5M]

3. a. Discuss abou the Employee Confidentiality Agreement under Trade Secret[5M]

b. Write about the Trade Secret Law with example.[5M]

4. a Write about confidentiality agreement between Employer and Employee. [8M]

b. Explain the spring board doctrine under the unfair competition law. [8M]

5. a. Write about employer–employee non-disclosure and non-competitive agreement.

[8M]

b. What is breach of trade secret? Explain the exception to it particularly for the

reverse engineering. [8M]

6. a. When a trade secret agreement is said to be violated and what are the remedies for

it? [8M]

b When information is called confidential information? What precautions a owner

of such information has to take to sustain it as such confidential information?

[8M]

UNIT-6 :CYBER LAW

1. a. What are various cyber crimes and explain about them. [8M]

b. What is the impact of internet on copyright? [8M]

2. a. What is data theft and internet hours theft? [8M]

b. Explain the duties and immunities of an internet service provider under

Information Technology Act.[8M]

3. a Explain the offence of hacking. What are the various provisions of the

Information Technology Act dealing with the offence of hacking? [8M]

b. What is sensitive personal data or information? How the sensitive personal

data[6M]

4. a. Explain the importance of Privacy policy of intermediaries like you tube and face

book. [8M]

b. Explain the offences of cyber terrorism and cyber extortion.[6M]

5. a. Explain „cyberspace‟ and impact of law.[5M]

b. Write about information technology Act-2000 [5M].

6. a Explain the crime of Cyber stalking. [5M]

b. Explain the methods of data security[5M]





DEPARTMENT ELECTRICAL&ELECTRONICS ENGINEERING

QUESTION BANK

Academic Year : 2017-2018 Name of the Faculty : A.N.S.Anusha Designation : Assistant Professor Department : Electronics&Communication Engineering Year/Semester : III/I Subject : Linear and Digital IC Applications

Unit-I

1. (a) Draw Block diagram of Typical Op–Amp With Various Stages and explain in detail.[5M]

(b) The common mode input of a certain differential amplifier, having differential gain of

125 is 4 sin 200_t V. determine the common mode output if CMMR 60dB. [5M]

2. (a) Analyze a dual input and unbalanced output BJT differential amplifier. [5M]

(b) For an op-amp PSRR is 70dB (min), CMRR is 105 and Ad= 105. The output voltage

changes by 20V in 4 sec. Calculate (i) common mode gain (ii) slew rate. [5M]

3. (a) Draw the circuit of BJT differential amplifier and suggest ways to improve CMRR. [5M]

(b) Write about level translator circuit. [5M]

4. (a) Analyze the circuit of a BJT differential amplifier with emitter resistance. [5M]

(b) Explain the operation of the BJT differential amplifier with constant current source. [5M]

5. Sketch a current mirror circuit and explain its operation. Show how a current mirror can be used

as a constant current circuit for a differential amplifier. Explain the circuit operation and discuss

its effect. [10M]

Unit-II

1. (a) Why is it necessary to use an external offset voltage compensating network with practical op

- amp circuits? [5M]

(b) Define slew rate and what causes it. How is the slew rate measured? [5M]

2. (a) What is the function of voltage regulator? Show the standard representation of IC voltage

regulator. [5M]

(b) List and explain the characters tics of three terminal IC regulator. [5M]

3. (a) Write about the advantages and disadvantages of 78xx and 79xx series regulators. [5M]

(b) An Op-Amp has a slew rate of 2V/μ sec. What is the maximum frequency of an output signal

of peak value 5V at which the distortion sets in due to the slew rate limitation? [5M]

4. (a) Listout DC and AC characteristics of opamp. [5M]





(b) Define the terms: PSRR, CMRR, input bias current & input offset voltage. Explain the

difference between slew rate and transient response. [5M]

5. (a)Define the Op-Amp parameters: (i) Input offset voltage, Vio (ii) Input bias current,

Iio with a practical setup explain how these parameters can be measured. [5M]

(b) Write about large signal voltage gain of op-amp. [5M]

Unit-III

1. (a)Design a differentiator to differentiate an input signal that varies in frequency from 10

Hz to about 1 KHz. If a sinewave of 1 V peak at 1000 Hz is applied to this differentiator,

draw the output waveforms. [5M]

(b) Define the terms Upper and Lower Tripping Points of a Schmitt trigger. What is the

significance of the two parameters? Explain the operation of a Schmitt trigger circuit

using Comparator. [5M]

2. (a)Draw a neat circuit diagram of an integrator circuit. Explain its functioning with

the Input-Output wave forms. Derive the output voltage V0 of an integrator circuit. [5M]

(b) With the help of a neat circuit diagram, explain the working of a logarithmic amplifier.Derive

the expression for its output voltage. [5M]

3. (a)What are the three differential amplifier configurations? Compare and contrast these

configurations. [5M]

(b) Explain the principle of operation of a precision full wave rectifier with waveforms.[5M]

4. (a) Design a differentiator circuit that will differentiate input signal with fmax = 100Hz. [5M]

(b) With the circuit diagram explain the working of Instrumentation Amplifier. [5M]

5. Discuss about following. [10M]

(a) Inverting Amplifier.

(b) Non inverting Amplifier.

(c) Summing Amplifier.

Unit-IV

1. (a)Draw and explain the operation of Mono stable multivibrator using 555 timer. Derive

the expression for time delay. [5M]

(b) Draw and explain the dc voltage versus phase difference characteristic of balanced modulator

phase detector of a PLL indicating all important regions. [5M]

2. (a) Design an astable multivibrator with 50 % duty cycle using 555 timer. [5M]

(b) Derive the expression for Time period of an astable multivibrator using 555 timer. [5M]

3. (a) Draw the block diagram of a 566 PLL IC and explain its working. [5M]

(b) Define the terms: i) free-running frequency f0 , (ii) lock range, (iii) capture range,

and (iv) pull-in time, pertaining to PLL. [5M]

4. (a)Explain the operation of VCO-565. [5M]

(b) Discuss about any two applications of 555 timer monostable multivibrator. [5M]

5. Explain the trigiring waveform generator using 555 timer. [10M]





Unit-V

1. (a) With the aid of a circuit diagram, explain the principle of operation of second-order

low pass active filter. [5M]

(b) Draw a band – pass filter circuit with its frequency response curve. Explain its

working. [5M]

2. (a)Explain the operation of an All-pass filter. Explain why it is known as phase shift

circuit. [5M]

(b) Design a band-pass active filter of second order with a mid-band voltage gain AR

VR=50. Center frequency fR 0R=200 Hz and Bandwidth=20 Hz. [5M]

3. (a) Explain the term ‘frequency scaling’ with suitable example. [5M]

(b) ) Draw the Ist order butter worth low pass and high pass filters and derive any ones frequency

response [5M]

4. (a) Design a second order low-pass Butterworth filter with a cut-off frequency of 12KHz and

unity gain at low frequency. Also determine the voltage transfer function magnitude in dB at

15Hz for the filter. [5M]

(b) Given a bandpass filter with resonant frequency fr of 1000 Hz and a bandwidth of 3000Hz;

Find its (i) quality factor, (ii) lower cutoff frequency and higher cutoff frequency. [5M]

5. (a)Design and explain the operation of first order wide band pass filter with its

characteristics? [5M]

(b) Explain the function of Wide band reject filter. [2M]

(c) Draw the frequency response characteristics of a notch filter. [3M]

Unit-VI

1. (a) Draw the circuit diagram of dual slope integration A to D converter and state its advantages.

Explain its operation with waveforms. What parameters decide its

conversion speed and accuracy? [5M]

(b) Discuss the operation of Ramp type ADC [5M]

2. (a) Write a short note on performance specifications of a digital to analog converter. [5M]

(b) Draw the circuit of weighted resistor DAC and derive expression for output analog

voltage Vo. [5M]

3. (a) Explain the operation of a multiplying DAC and mention its applications. [5M]

(b) Give the schematic circuit diagram of successive approximation type A/D converter

and explain the operation of this system. [5M]

4. (a)Sketch the circuit of a R-2R DAC, explain its operation, and calculate the analog output for

any given digital input. Explain the performance of R-2R DAC comparing with that of the

weighted-resistor DAC. [5M]

(b) Explain the operation of D/A converter with binary weighted resistors. [5M]





5. (a)What is the conversion time of a 10 bit successive approximation ADC if its input

clock is 5 MHz? [5M]

(b) Define the terms ‘Accuracy’, ‘Percentage Resolution’ and ‘settling time’ of an Analog to

Digital converter. [5M]

DADI INSTITUTE OF ENGINEERING & TECHNOLOGY (Approved by A.I.C.T.E., New Delhi & Affiliated to JNTU, Kakinada)

II B.TECH - I SEM Question Bank

Subject Name : MEFA Branch: EEE-A Faculty: Mr. A.KIRANKUMAR

Page 1 of 7

UNIT-1

1. Define Managerial Economics. Explain its Nature And Scope. 2. Discuss the importance of Managerial Economics in decision making. 3. What is Managerial Economics? Explain its focus areas. 4. Point out the importance of Managerial Economics in decision making. 5. Explain the role of a Managerial Economist in a Business Firm. 6. Define ‘Demand’ and explain the factors that influence the demand of a product. 7. Explain the various factors that influence the demand for computer. 8. What is meant by ‘Elasticity of Demand’? How do you measure it? 9. What is cross Elasticity of Demand? Explain

OR

Explain the concept of Cross Elasticity of Demand. Illustrate your answer with Examples.

10. Why does the Law of Diminishing Returns operate? Explain with the help of assumed data and also represent in a diagram.

11. What are the needs for Demand Forecasting? Explain the various steps involved in demand forecasting. 12. What are the possible approaches to forecasting demand for new products? Illustrate all the methods of

Demand Forecasting.

UNIT-II 1. Define Production Function. Discuss in detail the different types of production functions. 2. Define ‘Cost’. How are costs classified? Explain any five important cost concepts useful for managerial

decisions. 3. Discuss the role and importance of cost analysis in managerial decisions. 4. a) State and explain Break-Even analysis and explain its importance.

b) What are its limitations? Use suitable diagrams.

5. You are required to calculate. i) Margin of Safety ii) Total sales iii) Variable cost from the following figures; Fixed costs Rs. 12, 000; Profit Rs. 1, 000; Break-Even Sales Rs.60, 000

6. a) The information about Raj and Co., are given below. i) Profit-Volume Ratio (P/V Ratio) is 20% ii) Fixed costs Rs. 36000 iii) Selling price per Unit Rs. 150

b) Calculate:

a. BEP (in Rs.) b) BEP (in Units) c) Variable Cost per Unit d) Selling Price per Unit 7. A company reported the following results for two periods.

Period Sales Profit

I Rs.20,00,000 Rs.2,00,000

II Rs.25,00,000 Rs.3,00,000

Ascertain the BEP, P/V Ratio, Fixed cost and Margin of Safety.

8. Sales are Rs. 1, 10,000 Yielding a profit of Rs. 4,000 in period-I; Sales are Rs. 1, 50,000 with a profit of Rs. 12,000 in period-II. Determine BEP and Fixed Cost.

9. The P/V Ratio of Matrix Books Ltd is 40% and the Margin of safety is 30%. You are required to work out the BEP and Net Profit, if the Sales Volume is Rs.14,000




Page 2 of 7

10. A Company prepares a budget to produce 3, 00,000 Units, with fixed costs as Rs. 15, 00,000 and average variable cost of Rs.10 per unit. The selling price is to Yield 20% profit on Cost. You are required to calculate

a) P/V Ratio b) BEP in Rs and in Units.

11. You are given the following information about two companies in 2000

You are required to Calculate (For Both Companies)

1) BEP (in Rs.) 2) P/V Ratio 3) Margin of safety

UNIT-III

1. a) Define Market and explain how markets are classified? b) What are the important features in Market structure?

2. a) What is perfect competition? What are its features? b) How is market price determined under conditions of Perfect Market Competition?

3. a) Explain in detail, the important features of perfect competition b) How can a competitor attain equation position under conditions of perfect competition?

4. a) Explain the features of Monopoly. b) How can a Monopolist attain equilibrium position under conditions of monopoly?

5. What are the features of Monopolistic Competition? How can a firm attain equilibrium position? 6. Compare and contrast between Perfect competition and Monopoly. 7. Explain in detail about Maris and Williamson’s models. 8. a) What are the causes for the emergence of Monopoly?

b) How is the equilibrium position attained by a monopolist under varying cost conditions? Explain briefly on

Limit Pricing, Market Skimming,?

9. Write in detail about Internet Pricing- Flat rate pricing, Usage Sensitive, Transaction based pricing, Priority pricing.

UNIT-IV 1. a) What are the different types of Business organizations?

b) What are the features of Sole trading form of Organization?

2. a) What are the characteristics of a Business Unit? b) What are the characteristic features of a sole trader form of organization?

3. a) What are the salient features of Partnership firm b) Explain Different kinds of partners.

c) What are the advantages and limitations of partnership firm?

4. a) What do you mean by Joint Stock Company? What are the salient features? b) Describe the advantages and disadvantages of Joint Stock Companies?

5. a) Analyses the Formation of Joint Stock Company? b) What are the different types of companies?

6. Distinguish between the Joint Stock Company and Partnership.

Particulars Company A Company B

Sales Rs.50,00,000 Rs.50,00,000

Fixed Expenses Rs.12,00,000 Rs.17,00,000

Variable Expenses Rs.35,00,000 Rs.30,00,000




Page 3 of 7

7. What are the objectives behind starting public sector enterprises in the country? To what extent have they fulfilled these objectives?

8. Analyse the problems of the public sector enterprises and suggest remedial measures for their improvement.

UNIT-V

1. Give a brief account on the important records of Accounting under Double Entry System and discuss briefly the scope of each?

2. Explain the purpose of preparing the following accounts/statements and also elaborate the various items that appear in each of them.

a) Trading Account b) Profit & Loss Account c) Balance Sheet

3. Explain the following adjustments and illustrate suitably with assumed data. a) Closing stock b) Outstanding expenses c) Prepaid Income d) Bad debts

4. (a) Define the concepts ‘Accounting’, Financial Accounting and Accounting System’. (b) Explain the main objectives of Accounting and its important functions.

5. What do you understand by Double Entry Book Keeping? What are its advantages? 6. What is Trial Balance? Why it is prepared?

Illustration I

Journalize the following transactions and post them into Ledgers

Jan 1. Commenced business with a capital of Rs. 10000

,, 2. Bought Furniture for cash Rs. 3000

,, 3. Bought goods for cash from ‘B’ Rs. 500

,, 4. Sold goods for cash to A Rs. 1000

,, 5. Purchased goods from C on credit Rs.2000

,, 6. Goods sold to D on credit Rs. 1500

,, 8. Bought machinery for Rs. 3000 paying Cash

,, 12. Paid trade expenses Rs. 50

,, 18. Paid for Advertising to Apple Advertising Ltd. Rs. 1000

,, 19. Cash deposited into bank Rs. 500

,, 20. Received interest Rs. 500

,, 24. Paid insurance premium Rs. 200

,, 30. Paid rent Rs. 500

,, 30. Paid salary to P Rs.100




Page 4 of 7

Illustration-III

During January 2003 Narayan transacted the following business.

Date Transactions Amount

2003

Jan.1

,, 2

,, 3

,, 4

,, 5

,, 6

,, 7

,, 8

,, 9

,, 10

,, 11

,, 12

Commenced business with cash

Purchased goods on credit from Shyam

Received goods from Murthy as advance for goods ordered by him

Paid Wages

Goods returned to shyam

Goods sold to Kamal

Goods returned by Kamal

Paid into Bank

Goods sold for Cash

Bought goods for cash

Paid salaries

Withdrew cash for personal use

40000

30000

3000

500

200

10000

500

500

750

1000.

700

1000

Journalize the above transactions and prepare cash Account

Illustration V:

From the following list of balances prepare a Trial Balance as on 30-6-2003

Rs. Rs.

i Opening Stock 1800 xiii Plant 750

ii Wages 1000 xiv Machinery tools 180

iii Sales 12000 xv Lighting 230

iv Bank loan 440 xvi Creditors 800

v Coal coke 300 xvii Capital 4000

vi Purchases 7500 xviii Misc. receipts 60

vii Repairs 200 xix Office salaries 250

viii Carriage 150 xx Office furniture 60

ix Income tax 150 xxi Patents 100

x Debtors 2000 xxii Goodwill 1500

xi Leasehold premises 600 xxiii Cash at bank 510

xii Cash in hand 20




Page 5 of 7

Illustration VI Prepare a Trial Balance from the following Data for the year 2003.

Rs. Rs.

Freehold property 10800 Discount received 150

Capital 40000 Returns inwards 1590

Returns outwards 2520 Office expenses 5100

Sales 80410 Bad debts 1310

Purchases 67350 Carriage outwards(sales exp) 1590

Depreciation on furniture 1200 Carriage inwards 1450

Insurance 3300 Salaries 4950

Opening stock 14360 Book debts 11070

Creditors for expenses 400 Cash at bank 2610

Creditors 4700

Illustration: VII The following is the Trial Balance of Abhiram, was prepared on 31st March 2006. Prepare Trading and Profit& Loss

Account and Balance Sheet.

Debit Rs. Credit Rs.

Capital ------ 22000

Opening stock 10000 ------

Debtors and Creditors 8000 12000

Machinery 20000 -------

Cash at Bank 2000 -------

Bank overdraft ------ 14000

Sales returns and Purchases returns 4000 8000

Trade expenses 12000 -------

Purchases and Sales 26000 44000

Wages 10000 -------

Salaries 12000 -------

Bills payable ------- 10600

Bank deposits 6600 -------

TOTAL 110600 110600

Closing Stock was valued at Rs.60, 000

1. Explain the meaning of the ‘Analysis of Financial Statements’. Discuss briefly the different type of analysis. 2. How are ratios classified for the purpose of financial analysis? With assumed data, illustrate any two types of

ratios under each category 3. As a financial analyst, what precautions would you take while interpreting ratios meaningfully? 4. What are the limitations of Ratio Analysis? Does ratio analysis really measure the financial performance of a

company?




Page 6 of 7

UNIT-VI 1. What are the components of Working capital? Explain each of them.

2. a) What is the important of capital?

b) What factors determine the working capital requirements of company?

3. a) What is the importance of Capital budgeting?

b) How do the discounting models differ from non-discounting models?

4. Explain in detail about traditional and modern techniques of Capital Budgeting.

5. Examine the following three proposals and evaluate them based on

a) PBP Method

b) ARR Method. (ARR on original Investment)

Initial Investment is Rs.10, 00,000/- each for all the three projects.

6. Determine the Pay Back Period for the information given below

a) The project cost is Rs. 20,000

b) The life of the project is 5 years

c) The cash flows for the 5 years are Rs.10,000, Rs.12,000; Rs.13,000; Rs.11,000; and Rs. 10,000

respectively and

d) Tax rate is 20%

Year

Cash inflows (Rs.)

Project-A Project-B Project-B

1. 5,00,000 6,00,000 2,00,000

2. 5,00,000 2,00,000 2,00,000

3. 2,00,000 2,00,000 6,00,000

4. ------- 3,00,000 4,00,000




Page 7 of 7

7. Calculate the Net present value (NPV) of the two projects X and Y. Suggest which of the two projects should

be accepted assuming a discount rate of 10%

Item Project-A Project-B

Initial Investment Rs. 80,000 Rs. 1,20,000

Life Period 5 Years 5 Years

Scrap Value Rs.4,000 Rs.8,000

(Annual Cash Inflows) (CFAT) (CFAT)

Year: 1 Rs.24,000 Rs.70,000

,, 2 Rs.36,000 Rs.50,000

,, 3 Rs.14,000 Rs.24,000

,, 4 Rs.10,000 Rs.8,000

,, 5 Rs.8,000 Rs.8,000

8. A Company has at hand two proposals for consideration. The cost of the proposals in both the cases is Rs. 5, 00,000 each. A discount factor of 12% may be used to evaluate the proposals. Cash inflows after taxes are as under.

Year Proposals X(Rs.) Proposals Y(Rs.)

1 1,50,000 50,000

2 2,00,000 1,50,000

3 2,50,000 2,00,000

4 1,50,000 3,00,000

5 1,00,000 2,00,000

Which one will you recommend under NPV method

III B.TECH - I SEM Question-Bank Subject: POWER ELECTRONICS-Branch: EEEA & EEEB-Faculty: Ms. M. BABITA

UNIT I 1. a) Explain about snubber circuit and derive the condition for Rs? [8M] b) What is a MOSFET? Explain its V-I characteristics briefly. Also write its advantages over other switches. [8M] 2. a) Discuss about switching characteristics of an SCR during turn on and off. [8M]

b) Explain the diode bridge rectifier with R load and capacitive filter with neat circuit diagram and necessary

waveforms. [8M]

3. a) Explain various turn-on methods of an SCR. [8M]

b)A thyristor operating from a peak supply voltage of 400V has the following specifications: Repetitive

peak current, Ip = 200A, (di/dt)max= 50A/µs, (dv/dt)max = 200V/µs. Choosing a factor of safety 2 for Ip,

(di/dt)max and (dv/dt)max, design a suitable snubber circuit. The minimum value of load resistance is 10? [8M]

4. a) Explain the static V-I characteristics of a thyristors and different modes of operation. [8M]

b) Explain the diode bridge rectifier with R load and the output voltage waveform. [8M]

5. a) Briefly explain the V-I characteristics of an IGBT. [8M]

b) For a single phase half wave rectifier feeding a resistive load R, find the values of rectifier efficiency, form

factor, voltage ripple factor, transformer utilization factor and crest factor when α 00 . [8M]

6. a) Explain the transfer and output characteristics of MOSFETs. [8M]

b) Explain the basic operation of a SCR. [8M]

UNIT II a) Explain the operation of single phase half wave converter with RL load. Draw the output voltage waveform and derive the expression for average load voltage. [8M]

b) A single phase full-wave ac voltage controller feeds a load of R=20with an input voltage of 230V, 50Hz.

Firing angle for both the thyristors is 450. Calculate (i) rms value of output voltage. (iii) Average and rms

current of thyristors. [8M]

2. a) Explain RC firing circuit with suitable waveforms. [8M]

b) A 230V, 50Hz, one-pulse SCR controlled converter is triggered at a firing angle of 400 and the load current

extinguishes at an angle of 2100. Find the average output voltage and the average load current for R=5and L=2mH.

[8M]

3 a) What is UJT firing circuit and explain it with suitable waveforms? [8M]

b) A single phase half controlled bridge converter is supplied a 230V, 50Hz. Determine the average load

voltage for firing angle of 600. If load current of 30A is continuous and constant, what is the value of load

resistance? [8M]

4. a) Explain the operation of single phase AC voltage controller with R load. Draw the necessary waveforms. [8M]

b) A 230V, 1kW electric heater is fed through a single phase AC voltage controller from 230V, 50Hz Source. Find

the load power for a firing angle delay of 700. Derive the expression used. [8M]

5. a) Discuss the principle of phase control in single-phase full-wave ac voltage controller. Derive the expression for

the rms value of its output voltage. [8M]

b) A single phase full wave ac voltage controller controls load power. The input is 230V, 50 Hz. The load circuit

consists of R= 3and ωL = 4 .Determine (i) The control range of firing angle (ii) Maximum value of RMS load current (iii) Maximum power (iv) Power factor [8M]

6. a) 1- φ ,230V, 50HZ source connected to an anti parallel connected thyristor circuit;

controlling power to the following loads, when α = 900. Calculate output voltage, output current and load

power factor for (a) R=10 OHMS; L=0 H (b) R=10 OHMS; L=60mH. [8M]

UNIT III 1. a) Derive the expression for output voltage of single-phase full converter by considering source inductance.

[8M]

b) Single phase fully controlled converter is connected to a load comprised of 2ohms

resistance and 0.3H inductance. The supply voltage is 230V at 50Hz. Estimate the average load voltage,

average load current and input power factor for a firing angle of 200. Assume continuous and ripple free load

current. [8M] 2. a) Describe the working of single phase half controlled converter for = 30

o with relevant waveforms

and derive expression for average output voltage. [8M]

b) A 1- full converter bridge is connected to RLE load. The source voltage is 230V, 50Hz. The average load

current of 10A is constant over the working range. For R=0.4 and L=2mH, compute. i) Firing angle delay for

E=120V and ii) Firing angle delay for E= -120V. Indicate which source is delivered power to load in above cases.

[8M]

3.` a) Describe the working of single-phase fully controlled bridge converter in the Rectifying

mode and inversion mode. And derive the expressions for average output voltage

and rms output voltage. [8M]

b) Single phase fully controlled bridge is used for obtaining a regulated converter dc output voltage. The rms

value of ac input voltage is 220V and firing angle is maintained at 300, so that the load current is 4A.

(a) Calculate the d.c. output voltage and active and reactive power input. (b) Assuming load resistance remains same and if free-wheeling diode is used at the output, calculate dc output voltage. The firing angle is maintained at 30

0. [8M]

4 a) Derive the expressions for the following performance factors of single-phase fully

Controlled bridge converter. (i)Input power factor (ii) Voltage ripple factor (iii) Active power input (iv) Reactive

power input [8M]

b) The 1-semi converter circuit is connected to a 120V, 60 Hz supply. Determine the

harmonic factor, distortion factor and input power factor if delay angle is = /2. [8M]

5. Discuss the effect of source-inductance on the performance of a single phase fully controlled converter,

indicating clearly the conduction of various thyristors during one cycle. Derive an expression for its output voltage

in terms of Vm, α and µ. [16M]

6. a) A Single Phase semi converter with freewheeling diode across the load is operated from a 120-V,60-Hz

supply. The load current with an average value of Ia is continuous with negligible ripple content. If the firing

angle is Π/3, Calculate (a) the harmonic factor of input current (ii) displacement factor (iii) the input power factor

[10M]

b) A single phase fully controlled bridge converter is supplied at 230V, 50Hz, with source inductance of

2mH. When the converter is operating at a firing angle of 450 with ripple free load current of 10A, determine also

the load voltage. Neglect resistance voltage drop. [6M]

UNIT IV

1. Describe the working of three phase half controlled converter with R load for =30o

with relevant waveforms and derive the expression for average output voltage. [16M]

2. a) Briefly explain the operation of single-phase dual converter. [6M] b) A 3- fully controlled bridge converter is supplying DC-load of 400V, 60A from a 3 phase, 50Hz, 660V (line) supply. If the thyristors have a voltage drop of 1.2V when conducting, then neglecting overlap, compute. Firing angle of thyristor, RMS value of thyristor currents and Mean power loss in thyristors. [10M] 3Explain the operation of three phase fully controlled bridge converter with RL load. [16M] 4Draw the voltage and current waveforms for = 45

0. List the firing sequence of SCRs. [16M]

5.a) Sketch output wave form for a 3-phase semi converter for a firing angle delay of 75

0. Indicate the

conduction of various elements and discuss whether freewheeling diode comes in to place on the assumption of continuous load current. Hence obtain an expression for an average output voltage. [8M]

b) A 3-Phase full convertor is connected to a RLE load. The source voltage is 3-phase, 230V, 50 Hz and the load current is 10A. For R=0.5 and L=2H, determine (a) firing angle for E = 134V and (b) firing angle advance for E = -134V. [8M] 6a) Explain the operation of a three phase dual converter in the non circulating current mode with the help of relevant waveforms. Derive the expression for the average output voltage. [10M] b) A three phase fully controlled bridge converter is fed from a 3-phase 400 V, 50Hz mains. For firing angle of 60

0, output current is 25 A and output voltage is 250 V. Calculate the load resistance, source inductance and angle

of overlap. [6M]

UNIT V 1. a)Discuss the working of a single phase bridge type cycloconverter with RL loads and for discontinuous

waveform operation with neat circuit diagram and output rms voltage and current wave form for fo = (1/3) fs. [8M]

b)Explain the operation of Buck-Boost chopper with relevant waveforms and derive expression for average output voltage. [8M] 2. a) Discuss the working of a single phase bridge type cycloconverter with RL loads and for continuous waveform operation with neat circuit diagram and output rms voltage and current wave form for fo = (1/4) fs. [9M] b) Explain the operation of Boost chopper with relevant waveforms and derive the expression for average output voltage. [7M] 3. For a single phase mid-point Cyclo-converter, explain the operation of the circuit when fed to R-load with the help of neat circuit diagram and relevant output waveforms for = 30

0 and = 120

0 for f0 = 1/4 fs. [16M]

4 a) Describe the operation of a Boost converter and derive its output voltage equation. [8M]

b) For the ideal type A-chopper circuit, following conditions are given, Edc = 220V, chopping frequency, = 500 Hz,

duty cycle =0.3 and R = 1 ohm, L= 3 mH and Eb = 23V. Compute the following quantities (i) Average output current

(ii) maximum and minimum values of steady state output current [8M] 5. a) What is a DC-OC converter? Describe the working of Boost converter with relevant wave forms. Derive the expression for output voltage. [8M]

b) A dc battery is to be charged from a constant dc source of 220 V. The dc battery is to be charged from its

internal emf of 90 V to 122 V. The battery has internal resistance of 1 .With a constant charging current of 10A

compute the range of duty cycle. [8M] 6. a) Discuss the working of a single phase bridge type cyclo converter with RL load for continuous conduction operation with relevant output waveforms and circuit diagram for f0 = (1/4) fs. [8M] b) Explain the principle of operation of a Back- Boost converter. [8M]

UNIT VI 1. a) With a neat circuit diagram, explain the principle of operation of a single phase half bridge inverter. [6M] b) A single PWM full bridge inverter feeds an RL load with R = 10 ohms and L =10 mH. If the source voltage is 120V, find out the total harmonic distortion in the output voltage and in load current. The width of each pulse is 1200 and output frequency is 50Hz. [10M] 2. Explain the operation of three-phase bridge inverter for 180o mode of operation with aid of relevant phase and line voltage waveforms. [16M] 3. What are different applications of inverters? Explain the operation of 3ph bridge inverter for 120

o mode of

operation with aid of relevant phase and line voltage waveforms. [16M] 4a) With a neat circuit diagram, explain the principle of operation of a single phase full bridge inverter. [6M] b) A single phase full bridge inverter uses a uniform PWM with two pulses per half cycle for voltage control. Plot the distortion factor, fundamental component, and lower order harmonics against modulation. [10M]

5. a) What is the different pulse width modulation techniques used for inverters? [8M]

b) Explain unipolar switching scheme operation for a PWR inverter? [8M] 6 a) Explain the working of a single-phase half bridge inverter. Discuss how the output power in single-phase full bridge inverter becomes four times the power handled by a single phase half-bridge inverter. [8M]

b) Describe briefly and compare the various methods employed for the control of output voltage of inverters.

[8M]

DADI INSTITUTE OF ENGINEERING & TECHNOLOGY

(Approved by A.I.C.T.E., New Delhi & Affiliated to JNTUK, Kakinada)




SUB: Power Systems – II Name of the Faculty: R.V.S. Lakshmi Kumari

Sections: III EEE A & B Year: 3rd

Year SEM:1st

UNIT – 1

1. a) Find GMD, GMR for each circuit, inductance for each circuit and total inductance per meter for two

circuits that run parallel to each other. One circuit consists of three 0.25 cm radius conductors. The second

circuit consists of two 0.5 cm radius conductors as shown in the figure below:

b) Define Geometric mean distance in a transmission line?

2. a) Derive the expression for inductance of a three phase double circuit line.

b) Three conductors of three phase line are arranged at corners of triangle of sides 2m, 3.2m and 4m. The

diameter of the conductor is 2.5cm. Calculate the inductance and capacitance of a three phase three wire

system.

3. a) Derive the expression for the capacitance of a transposed unsymmetrical 3 phase system?

b) Derive the expression for the capacitance of a conductor in a double circuit hexagonal spaced three

phase system?

4. a) Derive the expression for the capacitance of a three phase line?

b) Calculate the loop inductance of a single phase line with two parallel conductors spaced 3.7m apart.

The diameter of each conductor is 1.5m?

5. a) What are bundled conductors? Discuss the advantages of bundled conductors, when used for overhead

lines.

b) A 3-phase, 50 Hz, 66 kV overhead transmission line has its conductors arranged at the corners of an

equilateral triangle of 3m sides and the diameter of each conductor is 1.5 cm. Determine the inductance

and capacitance per phase, if the length of line is 100 km. And also calculate the charging current.

UNIT – 2

1. a) Analyze a short transmission line with the help of phasor diagram?

b) A 220kv 50Hz 3 phase transmission line is 56km long. The resistance per phase is 0.14 ohms/km, the

inductance per phase is 1.32mH/km and the shunt capacitance is negligible. Use the short line model to

mailto:[email protected]

find the voltage and power at the sending end, voltage regulation and efficiency when the line is

supplying a 3 phase load of 400MVA, 220KV at 0.7 power factor lagging?

2. A three phase short transmission line has resistance and reactance per phase as 4.5ohms and 6.7 ohms

respectively. The sending end and receiving end voltages are 11kv and 100 KV respectively, for some

receiving end load at 0.8 power factor lagging calculate the output power, sending end power factor and the

efficiency of the line?

3. A three phase 50Hz transmission line, 100km long delivers 25MW at 100KV at 0.75 power factor lagging.

The resistance and reactance of the lines per phase per kilometer are 0.32 ohms and 0.57 ohms

respectively while the admittance is 2.5*10-6 mho/ km/ph. calculate the efficiency of the transmission by

using nominal π method?

4. a) Analyze a medium transmission line with nominal π method and draw the phasor diagram?

b) Analyze a medium transmission line with nominal T method and draw the phasor diagram?

5. A 3-phase, 3km long line delivers 3000 kW at a power factor of 0.8 lagging to a load. If the voltage at

the supply end is 11 kV, determine the voltage at the load end, percentage regulation, sending end power

factor and the efficiency of transmission. The resistance and reactance per km of each conductor are 0.4 ohm

and 0.3 ohm respectively.

UNIT – 3

1. a) Analyze the long transmission line by rigorous solution?

b) Derive the A, B, C, D constants when two transmission lines are connected in cascade?

2. a) Explain about the equivalent ‘T’ model of a long transmission line?

b) Explain about the equivalent ‘π ’model of a long transmission line?

3. A 3 phase 50Hz, 180km long transmission line has three conductors each of 0.6cm radius, spaced at the

corners of an equilateral triangle of side 4m. the resistance of each conductor is 0.2 ohm/km and the line

delivers 20MVA at 110kv at 0.85 lagging power factor, then find the A,B,C,D constants , sending end

voltage and current , efficiency, regulation of the line?

4. A three-phase, 50 Hz, 150 km long transmission line has three conductors each of 0.7 cm radius spaced at

the corners of triangle of sides 2 m, 3.5m and 4.5m. The resistance of each conductor is 0.4 ohms per km

and the line delivers 50 MVA at 132 kV and at a lagging p.f. of 0.85. Determine ABCD constants as long

line (both real and complex angle methods).

5. With reference to long transmission line, give physical interpretation of the terms of characteristic

impedance and propagation constant? What is meant by surge impedance?

UNIT – 4

1. a) Derive the reflection and refraction coefficients of a line terminated with a resistance? b) Discuss the concept of travelling waves on a transmission line?

2. a) Explain the transient behavior of a line when it is open circuited at the receiving end? b) A rectangular wave travels along a 500km line terminated with a resistance of 1000 ohms. The line has a resistance of 0.32 ohm/km and surge impedance of 400 ohm. If the voltage at the termination point after two successive reflections is 200kv. Find the amplitude of the incoming surge?

3. When the transmission line is terminated through a resistance, how do you find out the expressions of reflection and refraction coefficient?

4. A 500 kV, 2 μsec, duration rectangular surge passes through a line having surge impedance of 350

ohms and approaches a station at which the concentrated earth capacitance is 3 × 103 PF. Calculate the maximum value of surge transmitted to the second line.

5. The ends of two long transmission lines, A and C are connected by a cable B, 1km long. The

surge impedances of A, B, C are 400, 50 and 500 ohms respectively. A rectangular voltage wave of 25 kV magnitude and of infinite length is initiated in A and travels to C, determine the first and second voltages impressed on C.

UNIT – 5

1. a) What is meant by Ferranti effect and prove it in a transmission line? b) Explain about the effect of radio interference due to corona on the transmission lines? 2. a) Explain about the effect of charging current on the regulation of a transmission line? b) Discuss about the shunt capacitive compensation with phasor diagram?

3. a) What are skin and proximity effects on transmission lines? b) Find the critical disruptive voltage and the critical voltages for local and general corona on a 3- phase overhead transmission line, consisting of 3-stranded copper conductors spaced 2.5 m apart at the corners of an equilateral triangle. Air temperature and pressure are 210C and 73.6 cm of Hg respectively. Take conductor diameter 10.4 mm, irregularity factor 0.85, local and general surface factors 0.7 and 0.8 respectively. 4. Explain the phenomenon of corona. How can the corona loss be minimized in transmission lines? 5. a) What are the factors affecting corona? b) What is skin effect? On what factors does it depend?

UNIT – 6

1. a) Derive the expression for sag of a transmission line between two supports of equal heights? b) Discuss how the ice formation and wind are affecting the weight of the conductor? 2. a) Explain briefly about the string efficiency improvement methods?

b) Define String efficiency of suspension insulator string.

3. a) What is sag template? Explain the construction of pin type insulator. b) Derive the expression for string efficiency of a string of 3- insulators. 4. An overhead line has the following data: span length 185m, difference in levels of supports 5m,

conductor diameter 1.82cm, weight per unit length of conductor 2.5kg/m, wind pressure 49kg/m2 of projected area. Maximum tensile stress of the conductor 4250kg/cm2. Factor of safety 5. Calculate the allowable sag in meters at the lower support.

5. A three phase over head line is being supported by three discs suspension insulators, the potential

across the first and second insulators are 12 and 18 kV respectively. Calculate (i) the line voltage, (ii) the ratio of capacitance between pin and earth to self-capacitance of each unit, (iii) the string efficiency.

Electrical Machines-III

QUESTION BANK

Branch:EEE

Faculty name: P.Jagruthi

Year/sem/sec: III / I/ A

Designation:Asst. professor ( EEE)

UNIT-I

Single Phase Motors

1. a) Write the advantages of AC series motor. [3M]

b) Explain the working principle of a single phase induction motor. [7M]

2. a). Why single phase induction motor does not develop a starting torque? [5M]

b) Explain the need for a winding in a split phase induction motor. [5M]

3.a) Explain in detail about double field revolving theory. [5M]

b) Explain the working of a capacitor start single-phase induction motor. [5M]

4. Derive equation for forward slip and backward slip of a single phase induction motor.[5+5]M

5.a) Explain the constructional features of a single phase induction machine. [4M]

b) What are the drawbacks of A.C. Series motor? Explain. [4M]

6.a) Can AC series motor be started on no-load? Explain. [3M]

b) What are different types of single phase motors and what are their applications? [3M]

c) What are applications of AC series motors?[4M]

UNIT-II

Synchronous Generator Construction and Operation

1.a) Define Pitch factor of a synchronous machine. [6M]

a) Describe various types of A.C. generators indicating their applications. [4M]

2.a) Explain the principle of operation of a synchronous machine. [5M]

b) A 16 pole alternator has 144 slots. If the coil pitch is kept 5 slots, then calculate

its pitch factor.[5M]

3. (a) Derive the e.m.f equation of an alternator and explain how the induced e.m.f in the armature

winding is affected by (i) pitch factor and (iii) distribution factor.[6M]

b) What factors affect the size of alternator? [4M]

4.a) What is distribution factor? [3M]

b) Discuss the effect of armature reaction in an alternator. [8M]

5.a) Determine the frequency of a 8 pole alternator rotating at 375 R.P.M. If the no. of poles is doubled,

then what will be its new frequency? [7M]

b) What is armature reaction? [3M]

6.a) Explain the load characteristics of an alternator. [5M]

b) Determine the frequency of a 12 pole alternator rotating at 600 R.P.M. If the no. of poles is tripled,

then what will be its new frequency?[5M]

UNIT-III

Voltage Regulation of synchronous Generator

1. a) Define voltage regulation. [3M]

b) A 550V, 55kVA, 1-Phase alternator has an effective resistance of 0.2Ω. A field

current of 10 A produces an armature current of 200 A on short-circuit and an

electromotive force of 450 V on open circuit. Calculate the full load regulation

with 0.8 power factor lagging.[7M]

2. a). Explain the ampere-turn method for the determination of voltage regulation of an alternator [5M]

b) Explain two reaction analysis of salient pole machines with phasor diagram. [5M]

3.a) What is potier reactance? [3M]

b. The following data were obtained for the OCC of a 10 MVA, 13 kV, 3-phase, 50 Hz, (7M)

star-connected synchronous generator:

An excitation of 100 A causes the full-load current to flow during the short-circuit

test. The excitation required to give the rated current at zero p.f. and rated voltage is 290V.

(i) Calculate the adjusted synchronous reactance of the machine

(ii) Calculate the leakage reactance of the machine assuming the resistance to be

negligible

(iii) Determine the excitation required when the machine supplies full-load at 0.8 p.f.

lagging by using the leakage reactance and drawing the mmf phasor diagram. What is the voltage

regulation of the machine?

4.a) Explain two reaction analysis of salient pole machines with phasor diagram. [5M]

b) Determine the voltage regulation of a 2000V, 1-phase alternator giving a current of 100A at unity

power factor. From the synchronous impedance method test results,full load current is 100A and is

produced by a short circuit by a field excitation of 2.5A and an electromotive force of 500V is produced

on open circuit by the same excitation. The armature resistance is 0.8 Ohm. [5M]

5.a) Explain the merits and demerits of e.m.f and m.m.f methods. Explain the

assumptions made in each case.[5M]

b) A 3phase star connected alternator is rated at 1600 kVA, 13500 V. The armature

effective resistance and synchronous reactance are 1.5 Ohm and 30 Ohm

respectively per phase. Calculate the percentage regulation for a load of 1280 kW at power factor of 0.8

leading.[5M]

6.a). Explain synchronous impedance method to determine voltage regulation of an alternator. [5M]

b) A 1500 KVA, 6600V 3 phase star connected alternator with a resistance of 0.4 ohm and reactance of 6

ohm per phase, delivers full load current at power factor 0.8 lagging, and normal rated voltage. Estimate

the terminal voltage for the same

excitation and load current at 0.8 power factor leading. [5M]

UNIT-IV

Parallel Operation of Synchronous Generators

1.a) What are the advantages of load sharing? [4M]

b) Explain the role of synchronous generators operation when connected to an

infinite bus.[6M]

2. a) What is the effect of changing input for alternators operating in parallel? [5M]

b) Deduce an expression for the synchronizing torque on no load of a 3-phase

synchronous machine in terms of the line voltage V, the short circuit line current

Isc, the electrical angle of displacement Ө and the speed n in rev per sec.[5M]

3.Explain different synchronization methods used for synchronizing alternators [5M]

b) Two alternators working in parallel supply a lighting load of 300 kW and a motor load aggregating to

5000 kW at a power factor of 0.71. One machine is loaded to 5000 kW at 0.8 power factor lagging. What

is the load and power factor of the other machine? [5M]

4.a) Define autosynchronization. [4M]

b) What is synchronizing power and explain its role in load sharing during parallel

operation?[6M]

5. a) What is the need for parallel operation of alternators?[4M] b) Explain the division of load between two parallel alternators.[6M]

6.a) Derive the expression for load sharing between dissimilar alternators. [5M]

b) Two synchronous generators are connected to bus-bars having a constant voltage of

10000 00V. Generator A has an induced e.m.f. of 13000 22.6

0 V and a

reactance of 2 ohm; generator B has an e.m.f of 12500 36.90 V and a reactance of 3 ohms. Find the

current, KW and KVAr supplied by each generator.[5M]

UNIT-V

Synchronous Motor Operation

1.a) What is the difference between a synchronous motor and an induction motor?

Explain.[5M]

b) What is pull out torque of a synchronous motor? [5M]

2. Describe the effect of varying excitation upon armature current and power factor of Synchronous motor when the input power to motor is maintained constant. [5+5]M

3. Explain the construction and working of a synchronous -induction motor. [4+6]M

4. a) Explain the various starting methods of synchronous motor. [6+4]M

b)A 2000 V, 3-phase star-connected synchronous motor has an effective resistance and synchronous

reactance per phase of 0.2 ohms and 2.2 ohms respectively. The input is 800 kW at normal voltage and

induced line e.m.f is 2500 V. Calculate line current and power factor

5.a) What could be the reasons for failure in starting a synchronous motor? Suggest

different remedies.[5M]

b) What is hunting? Why is it essential to suppress hunting? Explain. [5M]

6. Draw and explain the phasor diagram of 3-phase synchronous motor when (i) it is over excited (ii) it is under excited. [10]

UNIT-VI

Synchronous Motor Performance and Starting

1.a) List different methods for starting of synchronous motors. [5M]

b) Show that locus of power of a synchronous machine is circle? Give the co-ordinates of power circle.[5M]

2. (a) What is a synchronous condenser? Explain its operation with the help of phasor diagram. What are

its applications? [5M]

(b) What are the factors that cause hunting? What are the effects

hunting? Explain the methods used to eliminate the hunting in synchronous motor.[5M]

3. a) Explain the working of a synchronous -induction motor. [5M]

b) What is hunting and how it can be suppressed? [5M]

4.a) Explain the phenomenon of hunting. [4M]

a) What is a synchronous condenser? Explain its operation. [6M]

5. a) Write short notes on synchronous induction motor. [4M]

b) The input to an 11000V , 3 phase star connected synchronous motor is 60A. The

effective resistance and synchronous reactance per phase are respectively 1Ωand

30Ω Find the power supplied to the motor, and the induced electromotive force for a power factor of 0.8

i) lagging ii) leading [6M]

6.a)How does a synchronous induction motor run initially? Explain? [4M]

a) With the help of a neat vector diagram, explain the operation of synchronous motor as synchronous

condenser.[6M]

unit i - diet.edu.indiet.edu.in/questionbanks/iii btech i sem/iii-eee-b-i-sem.pdf · dadi institute...

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