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

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

there was no residual magnetism in the field circuit

there was a break in the armature circuit

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Electrical Machines
Under which of the following conditions hunting of synchronous motor is likely to occur ?

Small and constant load.

Periodic variation of load.

Over-loading for long period.

Over-excitation.

Small and constant load.

Periodic variation of load.

Over-loading for long period.

Over-excitation.

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Electrical Machines
A 3 - ÃŽÂ¦, 6 pole, 50 Hz IM has a rotor speed of 987 rpm find rotor frequency?

0.70 Hz.

0.65 Hz.

0.75 Hz.

60 Hz.

0.70 Hz.

0.65 Hz.

0.75 Hz.

60 Hz.

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Electrical Machines
A separately-excited DC generator, running at rated speed, has 6 volts across its armature terminals with no field current. When field winding is excited with one ampere, the voltage builds up to 250 V at no load. In case field current is reduced to zero, with the speed remaining unaltered, the armature terminal voltage would be

more than 6 V

less than 6 V

zero

6 V

more than 6 V

less than 6 V

zero

6 V

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Electrical Machines
If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is

√(Pi/Pc)

Pi/Pc

Pc/Pi

(Pi/Pc)2

√(Pi/Pc)

Pi/Pc

Pc/Pi

(Pi/Pc)2

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Electrical Machines
A lap wound DC machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage of

400 V.

100 V.

200 V.

800 V.

400 V.

100 V.

200 V.

800 V.

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 Under which of the following conditions hunting of synchronous motor is likely to occur ?

Electrical Machines A 3 - ÃŽÂ¦, 6 pole, 50 Hz IM has a rotor speed of 987 rpm find rotor frequency?

Electrical Machines If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is

Electrical Machines A lap wound DC machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage of

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
Under which of the following conditions hunting of synchronous motor is likely to occur ?

Electrical Machines
A 3 - ÃŽÂ¦, 6 pole, 50 Hz IM has a rotor speed of 987 rpm find rotor frequency?

Electrical Machines
If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is

Electrical Machines
A lap wound DC machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage of