ELECTRICAL MACHINES QUIZ

In a DC machine

current and emf at the terminals are alternating.

current and emf in armature are unidirectional

current and emf in armature are alternating.

emf in armature conductors and at the terminals is alternating.

TRUE ANSWER : ?
YOUR ANSWER : ?

In a transformer maximum flux density is not constant, the eddy current loss varies as

V

f

V²

f²

TRUE ANSWER : ?
YOUR ANSWER : ?

A 6 pole lap connected DC generator with 480 conductors has armature resistance of 0.06 Ω. If the conductors are reconnected to from a wave winding other things remaining unchanged, the value of armature resistance will be

0.54 Ω.

0.01 Ω.

0.54 Ω.

0.06 Ω.

TRUE ANSWER : ?
YOUR ANSWER : ?

In which of the following generators negative voltage regulation can occur?

both B and C

shunt generator

over compound generator

series generators

TRUE ANSWER : ?
YOUR ANSWER : ?

In which transformer, the tertiary winding is used?

Star - delta

Star - star

Delta - star

Delta - delta

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YOUR ANSWER : ?

Capacitor fitted with ceiling / table fans is of the value of

2 - 3 µF.

5 - 10 F.

1 - 2 µF.

0.1 µF.

TRUE ANSWER : ?
YOUR ANSWER : ?

Two windings provided on the stator of 1-phase induction motor, one main winding and the other auxiliary winding are connected

through inductive coupling

either of these depending on the design of the motor

in parallel

in series

TRUE ANSWER : ?
YOUR ANSWER : ?

To eliminate the 5th harmonic in the induced voltages their respective pitch factor angle should be

18°

72°

30°

36°

TRUE ANSWER : ?
YOUR ANSWER : ?

If in DC Shunt Motor the flux is reduced suddenly to zero, then

the speed of motor will be reduced.

the armature current will reduce.

the motor will come to stop.

the motor will attain dangerously high speed.

TRUE ANSWER : ?
YOUR ANSWER : ?

The supply voltage to an induction motor is reduced by 10%. By what percentage, approximately, will the maximum torque decrease?

19%

5%

40%

10%

TRUE ANSWER : ?
YOUR ANSWER : ?

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