Biju Patnaik University of Technology 2008-5th Sem B.Tech (B Tech) instruments and measurements . - Question Paper
BPUT(B Tech) fifth semester instruments and measurements ques. paper.
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Total number of printed pages - 7 B. Tech
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CPEN 5306
Fifth Semester Examination - 2008
INSTRUMENTATION AND MEASUREMENTS
Full Marks-70
Time:3 Hours
Answer Question No. 1 which is compulsory and any five from the rest.
The figures in the right-hand margin indicate marks,
Draw appropriate diagrams whereever necessary.
All the symbols carry their usual meaning
1. Answer the following questions: 2x10
(a) A voltmeter having a range of 300V has an error of + 1% of full scale deflection, If the true voltage is 150V, what would be the range of readings ?
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(b) A voltmeter having a sensitivity of t KO N reads 90V on its 120V scale when connected across an unknown resistor in series with a mi III-ammeter, if the milli-ammeter reads 5mA, calculate the apparent resistance of the unknown resistor, (c) Give the expression for the critically damped motion of a dArsonval galvanometer. (d) Draw the equivalent circuit of a current - transformer. (e) How the reading of a wattmeter is atfeclVL if pressure coil inductance is taken Into consideration ? (f) Show how can you measure power in a three-phase balanced load using just one wattmeter. (g) For what condition the maximum torque is produced in an induction type of energy meter ? |
(h) State the principle of a vibrating reed type of frequency meter. (i) Which bridge(s) is (are) used for the measurement of self inductance ? (]) State two advantages of a digital meter over an analog meter of identical specifications. 2. An, Owens bridge is used to measure the properties of a sample of sheet steel at 2KHz, At balance, arm ab is test specimen; arm be is 100ft, arm cofis 0.1 F and arm da is a resistor of 839II in series with a capacitor of 0.124 pR Calculate from the fundamentals the effective impedance of the specimen under test conditions, 3, A current transformer having a \ turn primary is rated at 500/5A, 50Hz with an output of 15VA. At rated load with non-inductive burden the inphase and qudrature components of the exciting mmf are 3 and 10A respectively. The |
numt*f Of r*ecprttiarv is &0, and
fho rosjstaiKe ad u?ahL3c raactanca of y\r? soondry wining *nf 0 350 and 03CJ rnpegfevey Cateufaw from th* fundamnfjis ife current and pT>a$ angle *rot Dfavif ins egurvatent c*out diagram and phaso* Vagram
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4 A voltage TOO S*v 4 MXX&> t 30*) * 5Q*n (Sa*! + 45f) V is appiod to tf* prasMrrw of a wattmeter and ihrouflh *ho cyrwnj cod & pa&sod a cufftint of BsanuT6cos f&jn1*l?0|A
(a) What will be (horoadtng of thu waJtmetei t
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(b) What percortfagQ ot this power & du 10 fundamental ? 3
5. (a) A galvanometer has ifti following paraim* Jors . B sr 10x10 JWb'm\ N =200 turns, I = 16mm d a 16mm, K-10 *10 *WmAad, J=50xl0 1 kg*m?(Oi5 <10 JMm/rads \ The rijsilance of the coil is 120 U. Calculate
(i) the deflection of the galvanometer m radtan and wi mm wihen a constant current o* 1 n A flows tnrough H. ihe scale being t m away,
(ii) the frequency of (lamped oscillations and
M) the first maximum deflection. 6
lb) Bring om the essenbal dfferences between a d, Areonval type gakanomet&r arid ballistic galvanometer 4
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6 (a) In an electrical resonance deflectional type of frequency meter, there are two parallel circuits each consisting of an inductance and a capacitance in series. One circuit has C, 1 n F ahd is tuned to a frequency f,= 60Hz. The other has C?= 1.5 |iF and is tuned to a frequency of fa. below 50 Hz. The resistance of
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each circuit is R,= H2 = fQOO, What must be the inductance of the second circuit and to what frequency must it be tuned, in order that the current in both the circuits are the same at 50Hz ?6 (b) The meter constant of a 230V, 10A watthour meter is 1800 revolutions/KWh, The meter is tested at half load at rated voltage with unity power factor The meter is found to make 80 revolutions in 138s. Determine the meter error at half load. IWL |
8. Write short notes on any two (a) Piezoelectric transducer (b) Digital frequency meter (c) Creep in energy meters (d) Optical Transducers. |
7, (a) Discuss the working of a Drysdale polar type of potentiometer with ihe help of a neat diagram. 5
(b) Discuss the working of a CRO with the help of an appropriate block schematic.
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CPEN 5306
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CPEN 5306 6 Contd.
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Attachment: |
| Earning: Approval pending. |
