Machine+power system quiz

1➤ In a three-phase cage induction motor when a full voltage is applied to the stator winding, the rotor fails to start because the number of stator and rotor slots are either equal or have an integral ratio. Determine the phenomenon mentioned in the above context.

Cascade arrangementResistance controlCoggingCrawling

2➤ Which of the following options give the CORRECT abbreviation of FACTS?

Full wave alternating circuit transmission systemFlexible alternating circuit transmission systemFull wave alternating current transmission system Flexible alternating current transmission system

3➤ Name the motor which carries a single-phase exciting winding which is similar to the main winding of a single-phase induction motor that carries a distributed DC type winding

Compound motorRepulsion motorDC series motor DC shunt Motor

4➤ In this method by injecting voltage at slip frequency in the rotor circuit, the speed of an induction motor can be changed. Determine the method mentioned in the context.

Speed controlSecondary foreign voltage controlVoltage controlRotor resistance control

5➤ Which of the following is NOT included in routine tests of a circuit breaker?

Depreciation of circuit breakerMeasurement of resistance of the main circuits Operational tests One minute power frequency voltage dry withstand test

6➤ Which type of test is NOT included in DC motor maintenance and repair?

Bearings and lubricationBrush and commutator maintenanceReviewing the service historyLoad test of motor

7➤ Which of the following is NOT a track electrification system?

Two-phase AC systemDC systemThree-phase AC systemSingle-phase AC system

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

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

9➤ For unloaded transmission line, if the receiving end voltage is higher than the sending end voltage, then this condition is called:.

the Raman effectthe Ferranti effectthe switching effectthe Seebeck effect

10➤ The direction of rotation of a DC motor is given by:

Lenz’s lawFaraday’s lawFleming’s left-hand rule Fleming’s right-hand rule

11➤ Merz price system is used for the protection of:

transformers onlytransformers and alternatorstransformers and transmission linesalternators only

12➤ In an alternator at zero power factor lagging, the armature reaction:

is wholly demagnetisingis cross magnetisingis wholly magnetising does not affect

13➤ The maximum value of voltage unbalance which has been agreed between Indian Railways and supply authorities is.

2% voltage unbalance continuously4% voltage unbalance continuously7% voltage unbalance continuously5% voltage unbalance continuously

14➤ The number of turns on the primary of a current transformer is:

less than or more than secondaryequal to secondarymore than secondaryless than secondary

15➤ Which type of relay works by remotely closing but CANNOT remotely reclose the breaker?

Series trip electrostatic relaySeries trip magnetic relayShunt trip magnetic relay Capacitor start relay

16➤ The Sun-radiated solar energy on the surface of Earth on a normal sunny day is approximately:

100 W/m21500 W/m21 kW/m21320 W/m2

17➤ Which of the following steps is not included in preventive maintenance of electrical machine? .

EvaluationMeasurementTestingPlanning

18➤ Which method is NOT used for starting the synchronous motor?

Outer rolled machineSmall DC machinePony motor Damper winding

19➤ no-load current of the transformer is approximately ________ of the rated primary current.

3 to 5 % 50 %99 %90 %

20➤ Linear induction motor is used in

textile mills magnetic attractionmechanical workshoptraction

21➤ Which of the following parts is NOT connected in a DC machine?

Carbon brushesCommutatorDamper windingsArmature

22➤ Which of the following statements does NOT describe tidal energy?.

It is obtained due to alternating sea levelsIt is the kinetic energy from the natural rise and fall of tidesIt is a form of renewable energyIt is the energy derived from heating the ocean surface waters

23➤ Which of the following is an INCORRECT advantage of gas turbine power plants over diesel power plants?.

Gas turbine power plants display higher mechanical efficiency.The work developed per kg of air is largeGas turbine power plants have a comparatively longer lifeGas turbine power plants have lower installation and maintenance cost

24➤ A 300 V of separately excited dc generator is run at rated speed without excitation, terminal voltage on no load condition will be:

Half voltage 150 V300 V ZeroVery low 2 to 3 V

25➤ The electrical connections can be ensured between the commutator as well as exterior load circuit with the help of:

poles shoe ShaftPolesBrushes

26➤ Which type of test is NOT included for circuit breaker?

Work out test Dielectric testMaking capacity testMechanical test

27➤ Why are armature windings made on the rotor of a DC machine?

For electromechanical conversionFor commutationTo make rotation easy For production of voltage

28➤ Which of the following is NOT one of the advantages of a single three-phase transformer bank over a three single-phase transformer bank?

It occupies less space for same rating.It weighs lessThe core is of larger size which makes it robustThe cost is less

29➤ Which of the following is NOT necessary to be checked while maintaining stay wire?

Creeper on the stay wireGuy wire tightnessInclined length of stay wireCorrosion of guy rod and stay wire

30➤ In a three-phase induction motor, the number of rotor slots are:.

less than that of statormore than that of statorequal to that of statorequal to zero

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