A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The external resistance to be added in the armature circuit to limit the armature current to 125% of its rated value is

Electrical Machines
A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The external resistance to be added in the armature circuit to limit the armature current to 125% of its rated value is

31.9 Ω

15.1 Ω

15.9 Ω

31.1 Ω

31.9 Ω

15.1 Ω

15.9 Ω

31.1 Ω

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Electrical Machines
In large sized DC machines the compensating windings are provided to

neutralize voltage induced in coil due to fluctuation of l

None of these

reduce eddy current losses by providing local short circuits.

compensate for the decrease in speed due to increase of load.

neutralize voltage induced in coil due to fluctuation of l

None of these

reduce eddy current losses by providing local short circuits.

compensate for the decrease in speed due to increase of load.

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Electrical Machines
Copper brushes in DC machine are used

where high voltage and low current.

None of these

where low voltage and high currents are involved.

in both of above cases.

where high voltage and low current.

None of these

where low voltage and high currents are involved.

in both of above cases.

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Electrical Machines
In induction motors, there is large decrease in maximum power factor when the dispersion coefficient is ________________.

increased.

kept constant to certain value.

remains same.

decreased.

increased.

kept constant to certain value.

remains same.

decreased.

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Electrical Machines
What is the increase in the torque expressed as percentage of initial torque, if current drawn by the dc series motor is increased from 10A to 11A?

11%

21%

41%

10%

11%

21%

41%

10%

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Electrical Machines
For larger units high torque it is preferred to use

Partial motor.

DC shunt motor.

Slip induction motor.

Universal motor.

Partial motor.

DC shunt motor.

Slip induction motor.

Universal motor.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines

Electrical Machines In large sized DC machines the compensating windings are provided to

Electrical Machines Copper brushes in DC machine are used

Electrical Machines In induction motors, there is large decrease in maximum power factor when the dispersion coefficient is ________________.

Electrical Machines What is the increase in the torque expressed as percentage of initial torque, if current drawn by the dc series motor is increased from 10A to 11A?

Electrical Machines For larger units high torque it is preferred to use

Electrical Machines
In large sized DC machines the compensating windings are provided to

Electrical Machines
Copper brushes in DC machine are used

Electrical Machines
In induction motors, there is large decrease in maximum power factor when the dispersion coefficient is ________________.

Electrical Machines
What is the increase in the torque expressed as percentage of initial torque, if current drawn by the dc series motor is increased from 10A to 11A?

Electrical Machines
For larger units high torque it is preferred to use