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- Basic Electrical Engineering - BEE
- 2017
- PYQ
**Biju Patnaik University of Technology Rourkela Odisha - BPUT**- Electronics and Instrumentation Engineering
- B.Tech
**18758 Views**- 477 Offline Downloads
- Uploaded 2 years ago

Q3 a) An alternating voltage given by v 100sin 240t volts is applied across a coil of resistance 32 Ω. and inductance 100mH. Determine (a) the circuit impedance, (b) the current flowing, (c) the p.d. across the resistance, and (d) the p.d. across the inductance.(e) power factor of the complete circuit Write down the principle of operation of a DC generator. An 8-pole, waveconnected armature has 600 conductors and is driven at 625rev/min. If the flux per pole is 20mWb, determine the generated e.m.f. (10) a) Find the form factor and peak factor of the following wave form. (10) b) A silicon iron ring of cross-sectional area 5cm2 has a radial air gap of 2mm cut into it. If the mean length of the silicon iron path is 40cm, calculate the magnetomotive force to produce a flux of 0.7mWb. (5) a) What do you mean by transient of a response ? Derive the current growth and current fall equation for the R-L series circuit when DC battery is connected and disconnected respectively. The p.d. at the terminals of a battery is 25V when no load is connected and 24V when a load taking 10A is connected. Determine the internal resistance of the battery. (10) Explain the detail construction and principle of operation of an three phase induction motor ? Draw the torque-slip characteristics of the induction motor. If the voltage and current supplied to a circuit or load by a source are: Vs 230 300 V , I s 5300 A . Determine: A) The power supplied by the source which is dissipated as heat. B) The power stored in reactive components in the circuit (load). C) The power factor angle and power factor (10) a) State and explain Superposition theorem. With the help of Superposition theorem, compute the current I a b in the circuit. All resistances are in ohms. (10) b) What do you mean by half power frequencies ? Derive the half power frequencies for a R-L-C ac series circuit. (5) b) Q4 Q5 b) Q6 a) b) Q7 (5) (5) (5)

Q8 a) For the current i1 3 A, i2 10cos t A, and vc 5sin t V. Find (a) iL and vL (10) (b) vab , vbc and vcd (c) the energy stored in L and C as a function of time. Q9 b) Draw and explain the torque-speed characteristics of a three phase induction motor. (5) a) Write the advantages of three phase supply ? A delta connected balanced three phase load is supplied from a three phase,400V supply. The line current is 20 A and the power taken by the load is 10,000W. Find (i) Impedance in each branch (ii) the line current, power factor and power consumed if the same load is connected in star. (10) b) A coil has resistance of 300ohm and is switched on to a 110V d.c. supply.If the current reaches 62.3%of its final steady value in 0.002 second, determine (i)the time constant of the circuit (ii) the inductance of the circuit (iii)the maximum circuit current (iv) the initial rate of rise of current. (5)

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