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

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

less than 6 V

6 V

more than 6 V

zero

less than 6 V

6 V

more than 6 V

zero

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Electrical Machines
In dc machines, the space distribution of air-gap flux density wave at no load is

flat-topped

co- sinusoidal

rectangular

sinusoidal

flat-topped

co- sinusoidal

rectangular

sinusoidal

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Electrical Machines
A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is

36.36% increase

18.18% increase

36.36% decrease

36.36% increase

18.18% increase

36.36% decrease

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Electrical Machines
In 3 - ÃŽÂ¦ induction motor some times copper bars are placed deep in the rotor to

reduce copper loss.

improve efficiency.

improve starting torque.

improve power factor.

reduce copper loss.

improve efficiency.

improve starting torque.

improve power factor.

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Electrical Machines
With the increase in speed of a DC motor

both back emf as well as line current fall.

both back emf as well as line current increase.

back emf increases but line current falls.

back emf falls and line current increases.

both back emf as well as line current fall.

both back emf as well as line current increase.

back emf increases but line current falls.

back emf falls and line current increases.

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Electrical Machines
When the armature current of 5 Amp is flowing through the dc motor the torque produced is 47 Nm. Keeping the speed constant if the armature current is increased to 7 amp, calculate the new torque. Assume losses to be constant.

74 Nm.

27.73 Nm .

65.8 Nm.

38.5 Nm.

74 Nm.

27.73 Nm .

65.8 Nm.

38.5 Nm.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines

Electrical Machines In dc machines, the space distribution of air-gap flux density wave at no load is

Electrical Machines A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is

Electrical Machines In 3 - ÃŽÂ¦ induction motor some times copper bars are placed deep in the rotor to

Electrical Machines With the increase in speed of a DC motor

Electrical Machines When the armature current of 5 Amp is flowing through the dc motor the torque produced is 47 Nm. Keeping the speed constant if the armature current is increased to 7 amp, calculate the new torque. Assume losses to be constant.

Electrical Machines
In dc machines, the space distribution of air-gap flux density wave at no load is

Electrical Machines
A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is

Electrical Machines
In 3 - ÃŽÂ¦ induction motor some times copper bars are placed deep in the rotor to

Electrical Machines
With the increase in speed of a DC motor

Electrical Machines
When the armature current of 5 Amp is flowing through the dc motor the torque produced is 47 Nm. Keeping the speed constant if the armature current is increased to 7 amp, calculate the new torque. Assume losses to be constant.