The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be

Electrical Machines
The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be

59.2%.

48.0%.

57.1%.

88.8%.

59.2%.

48.0%.

57.1%.

88.8%.

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Electrical Machines
On what factors the speed of dc motor depends?

Applied voltage.

Armature current Ia.

All of these.

Field flux.

Applied voltage.

Armature current Ia.

All of these.

Field flux.

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Electrical Machines
On switching a DC motor to DC supply mains, it is found to rotate in the direction opposite to that for which it is designed. The DC motor is

Differentical compound.

Series shunt.

Cummulative compound.

have an equal number of electrons and protons.

Differentical compound.

Series shunt.

Cummulative compound.

have an equal number of electrons and protons.

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Electrical Machines
Armature reaction in dc motor results

increase in speed.

decrease in speed.

short circuit.

open circuit.

increase in speed.

decrease in speed.

short circuit.

open circuit.

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Electrical Machines
Magnetic field of a DC generator is produced by what?

Both B and C.

None of the options.

Electromagnets.

Permanent magnets.

Both B and C.

None of the options.

Electromagnets.

Permanent magnets.

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Electrical Machines
Hunting in a synchronous motor takes place

when load varies.

when power factor is unity.

when supply voltage fluctuates.

motor is under loaded.

when load varies.

when power factor is unity.

when supply voltage fluctuates.

motor is under loaded.

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Electrical Machines

Electrical Machines The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be

Electrical Machines On what factors the speed of dc motor depends?

Electrical Machines On switching a DC motor to DC supply mains, it is found to rotate in the direction opposite to that for which it is designed. The DC motor is

Electrical Machines Armature reaction in dc motor results

Electrical Machines Magnetic field of a DC generator is produced by what?

Electrical Machines Hunting in a synchronous motor takes place

Electrical Machines
The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be

Electrical Machines
On what factors the speed of dc motor depends?

Electrical Machines
On switching a DC motor to DC supply mains, it is found to rotate in the direction opposite to that for which it is designed. The DC motor is

Electrical Machines
Armature reaction in dc motor results

Electrical Machines
Magnetic field of a DC generator is produced by what?

Electrical Machines
Hunting in a synchronous motor takes place