ELECTRICAL MACHINES QUIZ

On which of the following factor/factors the speed of a DC motor depends upon?

Armature current.

Applied voltage.

All of these.

Field flux.

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In speed control of DC Series motor, speed lower than the rated speed can be obtained by

Any of the above.

Connecting an additional resistance in the field circuit.

Connecting an additional resistance in stator circuit.

Connecting an additional resistance in the armature circuit.

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A 4 pole 50 Hz induction motor is running at 1470 rpm. What is the slip value?

0.4

0.2

0.04

0.02

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In a transformer which of the following losses are zero?

All of these

Copper loss

Iron loss

Rotational loss

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If a DC Series motor is connected across an AC supply it will

not run.

run at lower speed.

run at normal speed.

burn.

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The main purpose of providing tertiary winding in a three phase transformer is

None of these

to carry extra load.

to suppress harmonic and unbalance in voltage.

to interconnect three voltage systems.

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Generator works on the principle of production

both A and B.

None of these

static induced emf.

dynamically induced emf.

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If any two leads from slip rings are interchanged in a 3 - ÃŽÂ¦ induction motor, the motor will

run in a direction opposite to previous one.

get damaged.

not run.

continue running in the same direction as before.

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What is the full form of MNP?

Magnetic neutral pole.

Magnetic neutral plane.

Magnetic field neutral plane.

Magnetic field neutral pole.

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What is the effect of armature reaction ?

None of the options.

Both option B and C.

Armature flux distorts the main field flux.

Armature flux weakens the main field flux.

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