Maharashtra State Board of Technical Education 2008 Diploma Electrical and Electronics Electrical Measurement - Question Paper

Sample ques. Paper – I
Course Name :- Electrical Engineering Group
Course code :- EE/EP
Semester :- Third
Subject :- Electrical Measurement
Duration :- three hours Marks: 80

Instructions :

1) All ques. are compulsory

2) Illustrate your answers with neat sketches wherever necessary.

3) Figures to the right indicate full marks.

4) presume suitable data, if necessary.

5) Preferably, write the answers in sequential order.


Q.1 Attempt any 8 of the subsequent [Marks:16]

a) Distinguish ranging from absolute and secondary instrument.

b) List the methods of providing controlling toque in indicating instruments.

c) State working principle of dynamometer kind wattmeter.

d) A single phase wattmeter rated for 500 V, 10 A is having full scale deflection of 1250 watt; what is the multiplying factor of the wattmeter?

e) List the errors in an induction kind energy meter.

f) State the meaning of creeping? How it is prevented in energy meter.

g) What kind of indication is given in phase sequence indicator.

h) State the working principele of single phase power factor meter.

i) Which method is used to determine the insulation resistance.

j) State the limits of earth resistance as laid down by statutory rules.

Q.2 Attempt any 3 of the subsequent [Marks:12]

a) State the properties for a good control torque system ? Which material is used for control spring? elaborate its needed properties?

b) Draw a neat sketch and tag the parts of PMMC kind ammeter.

c) Draw a block diagram of digital wattmeter.

d) A moving coil instrument provide a full scale deflection with 10 mA and has a resistance of 50 ohm. compute the resistance necessary to be put in series/ parallel with the instrument in order that is may be used as - (i) 0 - five A ammeter, (ii) 0 - 200 V voltmeter.

Q.3 Attempt any 3 of the subsequent [Marks:12]

a) State the 2 advantages and disadvantages of moving coil and moving iron instruments.

b) A PMMC meter of 0 - 250 V range is connected across single phase 230 V, 50 Hz supply. What will be studying on the meter? Justify your ans.

c) Draw a net sketch and tag the parts of dynamometer kind wattmeter.

d) A studying of 2 wattmeter connected to measure total power in a 3 phase 3 wire circuit are 10 Kw and one Kw; the later studying being found after reversal of pressure coil connections. compute the total power and power factor of the load.

Q.4 Attempt any 4 of the subsequent [Marks:16]

a) A subsequent data refer to a moving coil voltmeter, resistance = 10000 ohm, dimensionof coil = three cm x three cm, number of turns of coil = 100, flux density in air gap = 0.08 Wb/m², spring constant = three x 10^-6 Nm per degree. obtain the deflection produced by 200 V.

b) How the connection errors are compensated in dynamometer kind wattmeter.

c) Draw neat sketch, tag the parts of 3 element kind 3 phase 4 wire energy meter.

d) provide specifications of single phase induction kind energy meter as provided on its name plate. Can induction kind energy meter be used for measurement of energy in DC circuit. Justify your ans.

e) State the instrument used for measurement of low, medium, high resistance and earth resistance.

f) Draw neat sketch and tag the various parts of synchroscope.

Q.5 Attempt any 3 of the subsequent [Marks:12]

a) define the circuit and working of a Q meter.

b) define the principle of the wheatstone bridge and derive the formula for balance condition.

c) discuss the connection and working of phase sequence indicator.

d) State the uses of CT's and PT's.

Q.6 Attempt any 3 of the subsequent [Marks:12]

a) List the volumes measured by digital multimeter.

b) A single phase energy meter has a constant of 6000 Rev/kWh. A test was carried out with resistive load for 1 minute during which the meter made 21 Rev. The voltage was 110 V and current 2A; compute percentage fault.

c) A Kelving double bridge having ratio arm P=Q=p=q=1000 ohm. The emf of battery is 100 V and resistance of five ohm is included in battery circuit. The galvanometer has a resistance of 500 ohm and the resistance of the link connecting the unknown resistance to the standard resistance my be neglected, the bridge is balanced when
standard resistance S=0.001 ohm. Determine the value of unknown resistance.

d) Draw a block diagram of electronic energy meter.

Earning:   Approval pending.