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 no residual magnetism in the field circuit

there was a break in the armature circuit

field winding was wrongly connected

field resistance was higher than critical resistance

there was no residual magnetism in the field circuit

there was a break in the armature circuit

field winding was wrongly connected

field resistance was higher than critical resistance

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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

15.9 Ω

31.9 Ω

15.1 Ω

31.1 Ω

15.9 Ω

31.9 Ω

15.1 Ω

31.1 Ω

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Electrical Machines
Which of the following statement is correct, if short circuit ratio is high?

Good voltage regulation

High voltage regulation

Low short circuit current

None of these

Good voltage regulation

High voltage regulation

Low short circuit current

None of these

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Electrical Machines
Wave winding is employed in DC machine of

high current and low voltage rating.

low current and low voltage rating.

low current and high voltage rating.

high current and low voltage rating.

low current and low voltage rating.

low current and high voltage rating.

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Electrical Machines
A single phase transformer has specifications as 250 KVA, 11000 V/415 V, 50 Hz. What are the values of primary and secondary currents?

primary = 11.4 A, secondary = 301 A

primary = 22.7 A, secondary = 602.4 A

primary = 301 A, secondary = 22.7 A

primary = 602 A, secondary = 22.7 A

primary = 11.4 A, secondary = 301 A

primary = 22.7 A, secondary = 602.4 A

primary = 301 A, secondary = 22.7 A

primary = 602 A, secondary = 22.7 A

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Electrical Machines
No load test of 3-phase induction motor gives which of the following?

both A and B

variable loss

None of these

constant loss

both A and B

variable loss

None of these

constant loss

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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 Which of the following statement is correct, if short circuit ratio is high?

Electrical Machines Wave winding is employed in DC machine of

Electrical Machines A single phase transformer has specifications as 250 KVA, 11000 V/415 V, 50 Hz. What are the values of primary and secondary currents?

Electrical Machines No load test of 3-phase induction motor gives which of the following?

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
Which of the following statement is correct, if short circuit ratio is high?

Electrical Machines
Wave winding is employed in DC machine of

Electrical Machines
A single phase transformer has specifications as 250 KVA, 11000 V/415 V, 50 Hz. What are the values of primary and secondary currents?

Electrical Machines
No load test of 3-phase induction motor gives which of the following?