DOCKS AND HARBOR ENGINEERING QUIZ

No load saturation characteristics are plotted between

short circuit current and armature current

short circuit current and field current

no load voltage and armature current

no load voltage and field current

TRUE ANSWER : ?
YOUR ANSWER : ?

The flux involved in the emf equation of a transformer has

average value.

total value.

rms value.

maximum value.

TRUE ANSWER : ?
YOUR ANSWER : ?

A 4 pole, 3-phase induction motor is running at 4% slip at full load. If the speed of the motor is 720 rpm, the supply frequency is

25 Hz

40 HZ

50 Hz

60 Hz

TRUE ANSWER : ?
YOUR ANSWER : ?

On what factors the speed of dc motor depends?

Field flux.

Armature current Ia.

Applied voltage.

All of these.

TRUE ANSWER : ?
YOUR ANSWER : ?

For a DC machine having P no of pole pairs Z no of conductors having length L of resistivity ρ and cross section S are arranged. what is the armature resistance for lap-winding ?

PZL/4SP²

PZL/ 4Sa

PZL/4Sa²

PZL/4S

TRUE ANSWER : ?
YOUR ANSWER : ?

The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that

both Eb and Td are zero

both Eb and Td are unchanged

Eb is unchanged, but Td is zero

Eb is zero, but Td is unchanged

TRUE ANSWER : ?
YOUR ANSWER : ?

In case the conditions for maximum power for DC motor are established, the efficiency of the motor will be

Less than 50 %

Around 90 %

Any where between 75 % and 90 %.

Around 100 %.

TRUE ANSWER : ?
YOUR ANSWER : ?

Ideal value of voltage regulation of a device is?

a finite negative value

0

a positive finite value

∞

TRUE ANSWER : ?
YOUR ANSWER : ?

Swinburne test is conducted under which of the following condition?

any of the above

full load

half load

no load

TRUE ANSWER : ?
YOUR ANSWER : ?

Armature coil is short circuited by brushes when it lies

along neutral axis.

in any of above positions.

along field axis.

in none of above positions.

TRUE ANSWER : ?
YOUR ANSWER : ?

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