Machine+P.S MCQ part 2

1➤ Which of the following losses is least significant while calculating the efficiency of a DC machine?

Mechanical lossField copper lossIron lossArmature copper loss

2➤ The earth resistance of any earthing wiring should NOT be more than ______.

0.5 ohms 5 ohms500 ohms50 ohms

3➤ Which of the following is related to functioning of isolator?.

Disconnection under short circuit conditionsDisconnection under surge over voltageDisconnection in case of rapid fluctuations in load Disconnection under no load condition for safety isolation and maintenance

4➤ (Demand factor) × (Connected load) = ______.

Average load Load factor Maximum demandPlant use factor

5➤ Which of the following is an intermediate power plant?

Hydro-electric power plantFuel cell plantGas turbine power plantSolar power plant

6➤ For which of the following is the turns ration equal to 1?

Distribution transformerInstrument transformerStep down transformerIsolation transformer

7➤ power factor of pure capacitive circuit /power factor of pure resistive circuit = ________.

0-1Infinity 1

8➤ If the roughness of the conductor surface is increased, then the corona inception voltage:.

becomes infiniteremains unchangedis decreasedis increased

9➤ For a lap wounded DC machine, nubmber of poles /number of brushes = ________.

4321

10➤ For a short pitched synchronous machine, (distribution factor) × (pitch factor) is:

always zeroalways less than 1 always greater than 1always equal to 1

11➤ State whether the following statements are true or FALSE. 1. Salient pole rotor alternators have non-uniform airgap. 2. Salient pole rotor alternators are mechanically robust.

Both 1 and 2 are true.Both 1 and 2 are false1 is false but 2 is true. 1 is true but 2 is false

12➤ If the height of the transmission tower is decreased, the capacitance of the line to earth will:

increasedecreaseremain the samedecrease exponentially

13➤ VAWT related to wind turbine denotes:

Volt Ampere Wind TurbineVariable Axis Wind TurbineVariable Area Wind TurbineVertical Axis Wind Turbine

14➤ The method of finding the centre of gravity of a square is same as that of a:

rectangletrianglesemi-circlehemi-sphere

15➤ Fire point and flash point are the terms related to which of the following power plants?

Solar power PlantHydro power plantNuclear power plantDiesel power plant

16➤ Which of the following is NOT an application of high resistivity material?

Overhead transmission lineHeaterStarterOven

17➤ The resistance of an earthing electrode should be:

very low100kinfinite1k

18➤ In a power system, 3-phase, 4 wire system is normally used for:

secondary transmissionprimary transmissionsecondary distributionprimary distribution

19➤ The capacitor in a capacitor start induction motor is placed in:

series with running windingseries with starting windingseries with both running and starting windingseries with either running or starting winding

20➤ Inverse definite minimum time lag relay is also called ___________

directional overcurrent relaydifferential relayover current relay.pilot relay

21➤ A ceiling fan uses

capacitor start motor universal motorcapacitor start and capacitor run motorsplit-phase motor

22➤ High frequency transformers sometimes make use of ferrite cores because it has

High hysteresislow permeabilityHigh resistanceHigh specific gravity

23➤ Squirrel cage bars placed in the rotor pole faces of an alternator help reduce hunting

Above and below synchronous speeds bothNone of the other three Below synchronous speed onlyAbove synchronous speed only

24➤ A synchronous machine is called as doubly excited machine because

It needs twice the normal exciting currentBoth its rotor and stator are exciteIt has two sets of rotor poles It can be over excited

25➤ During open circuit test of a transformers

Primary is supplied rated kVAPrimary is supplied current at reduced voltagePrimary is supplied full load current Primary is supplied rated voltage

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