JNTU
JNTU B.Tech II ELECTRICAL ENGINEERING Previous Question Paper (May - 2019 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks.
PART- A
State Ohm’s law and write the limitations of the ohm’s law.
Answer
Ohm's law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, provided the temperature and physical conditions remain constant, expressed as V = IR. Its limitations are that it does not apply to non-linear devices like diodes, transistors, or vacuum tubes, and it is not applicable to non-metallic conductors like silicon carbide or electrolytes where the relationship between voltage and current is non-linear.
Define Self and mutual inductances.
Answer
Self-inductance is the property of a coil by which it opposes any change in the current flowing through it by inducing an electromotive force (EMF) in itself. Mutual inductance is the property by which a change in current in one coil induces an EMF in an adjacent coil due to the linkage of magnetic flux.
Find the rms value of the a-c voltage v(t) = 200 sin 314t.
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A balanced star connected load is supplied from a balanced 3phase 400V system. The current in each phase is 30 Amps and is 30 degrees behind the phase voltage. Find the total power taken by the load.
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Write principle of operation of DC generator.
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Write the significance of Back EMF in DC motors.
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The emf per turn for a single phase, 2310/220 V, 50 Hz transformer is approximately 13 volts. Calculate the number of primary and secondary turns.
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Write the differences between squirrel cage induction motor and slip ring induction motor.
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Why voltage regulation of an alternator is negative for leading power factor.
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What is the advantages and limitations of synchronous impedance method.
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PART-B
A resistor of 10 ohm is connected in series with two resistors of 15 ohm arranged in parallel. What resistance must be shunted across the parallel combination so that the total current taken shall be 1.5A with 20V applied.
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Find out the equivalent Resistance between AB terminals for the following circuit shown in figure 1 and all Resistance values are in ohms.
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Briefly classify different types of instruments.
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Explain principle and operation of moving iron voltmeter with diagram.
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Derive average and RMS values from the fundamental of Alternating current.
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Determine the overall current and power factor of the following circuit shown in figure 2.
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A series RLC circuit with R=100 Ω, L = 0.5H, C=40×10^-6 F has an applied voltage of 110∠0 with variable frequency. Calculate the resonance frequency, current at resonance.
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Three identical coils each of resistance 30 Ohms and inductance 127.3mH are connected in delta to a 440 V, 50 Hz, three-phase supply. Determine: (i) The phase current. (ii) The line current.
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Classify DC generators and derive EMF equation for DC Generators.
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Draw and Explain Load characteristics of DC shunt generators.
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Explain swinburn’s test when the machine act as DC motor.
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Explain Different types of speed control on DC shunt motors.
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Explain principle of operation of single phase transformer.
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Explain how can OC and SC test on 1-ϕ Transformer be conducted?
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Explain Principle and operation of three phase induction motors.
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Draw and explain torque-slip characteristics 3-ϕ of induction motors.
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With a neat sketch, explain the working of an alternator.
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Explain regulation of alternator by synchronous impedance method.
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