PGCIL JE Quiz 5

1➤ In DC generator, the electricity produced in armature is

1 pointACDCarmature is not present in DC generator.None

2➤ Commutators in DC machines have a role of which converts

1 pointhigh voltage DC to low voltage DCBoth AC to DC and DC to AC.AC to DC.Pulsating AC

3➤ Eg (generated emf) and Eb (back emf) both are

1 pointchangesdifferent.sameNone

4➤ Which machine is used for battery charging?

1 pointCompounded DC generator.DC series generator.DC shunt generator.All of These

5➤ Armature reaction in DC generators will result in

1 pointincrease in slip.open circuitshort circuitreduction in generated emf

6➤ In a DC machine, which of these parameters remain the same whether it runs as a DC motor or a DC generator?

1 pointMechanical powerArmature currentInduced emfCan not be determined

7➤ For high current and low current rating which winding is employed to DC machine?

1 pointWave windingLap windingBothNone

8➤ If direct axis reactance Xd and quadrature axis reactance Xq are equal, then reluctance power is

1 pointzeromaximumminimumInfinite

9➤ Addition of 0.3 % to 4.5 % silicon to iron

1 pointreduces the saturation magnetizationincreases the hysteresis loss increases the electrical resistivity of ironNone

10➤ A laminated iron core has reduced eddy current losses because

1 pointmore wire can be used with less dc resistance in coilthe lamination are insulated from each otherthe magnetic flux is concentratedthe lamination are stacked vertically

11➤ The torque speed characteristics of a AC servomotor is approximately

1 pointlinearisedparabolahyperbolaCircular

12➤ DC machine is a

1 pointconduction machine convection machineBothNone

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