A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because

Electrical Machines
A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because

there was a break in the armature circuit

field resistance was higher than critical resistance

there was no residual magnetism in the field circuit

field winding was wrongly connected

there was a break in the armature circuit

field resistance was higher than critical resistance

there was no residual magnetism in the field circuit

field winding was wrongly connected

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
In shunt dc motor the direction of rotation of the motor will reversed. When

only armature terminals are reversed.

none of above.

either field terminals are reversed or armature terminals are reversed.

only field terminals are changed.

only armature terminals are reversed.

none of above.

either field terminals are reversed or armature terminals are reversed.

only field terminals are changed.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Armature reaction in a DC machine

makes an angle with the main pole axis which is load dependent.

is in the same direction as the main poles.

is in direct opposition to the main poles.

makes an angle of 90° with the main pole axis.

makes an angle with the main pole axis which is load dependent.

is in the same direction as the main poles.

is in direct opposition to the main poles.

makes an angle of 90° with the main pole axis.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
If Ke is eddy current constant, Kf is form factor, f is supply frequency, Bm maximum flux density in core of transformer, the expression of eddy current loss in transformer, is given by

KefKf2Bm2.

Kef2Kf2Bm.

Kef2KfBm2.

Kef2Kf2Bm2.

KefKf2Bm2.

Kef2Kf2Bm.

Kef2KfBm2.

Kef2Kf2Bm2.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Which of the following alternators contain large number of poles?

Turbo alternators.

Aame in both alternators.

Hydro alternators.

None of these

Turbo alternators.

Aame in both alternators.

Hydro alternators.

None of these

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
The supply voltage to an induction motor is reduced by 10%. By what percentage, approximately, will the maximum torque decrease?

5%

40%

19%

10%

5%

40%

19%

10%

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines

Electrical Machines A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because

Electrical Machines In shunt dc motor the direction of rotation of the motor will reversed. When

Electrical Machines Armature reaction in a DC machine

Electrical Machines If Ke is eddy current constant, Kf is form factor, f is supply frequency, Bm maximum flux density in core of transformer, the expression of eddy current loss in transformer, is given by

Electrical Machines Which of the following alternators contain large number of poles?

Electrical Machines The supply voltage to an induction motor is reduced by 10%. By what percentage, approximately, will the maximum torque decrease?

Electrical Machines
A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because

Electrical Machines
In shunt dc motor the direction of rotation of the motor will reversed. When

Electrical Machines
Armature reaction in a DC machine

Electrical Machines
If Ke is eddy current constant, Kf is form factor, f is supply frequency, Bm maximum flux density in core of transformer, the expression of eddy current loss in transformer, is given by

Electrical Machines
Which of the following alternators contain large number of poles?

Electrical Machines
The supply voltage to an induction motor is reduced by 10%. By what percentage, approximately, will the maximum torque decrease?