Electrical Machines Mock Test 2

10%

Question 1 of 10

1. In a DC motor, the commutator serves as a ___________

all of the mentioned

mechanical inverter to invert the direct applied voltage to alternating voltage

mechanical rectifier for alternating EMF to direct EMF

none of the mentioned

Question 1 of 10

Question 2 of 10

2. A consideration of the power losses in electrical machines is essential for which of the following reasons?

Voltage drops

All of the mentioned

Temperature rise

Operating cost

Question 2 of 10

Question 3 of 10

3. No load rotational losses in electrical machine consists of _____________

Stator core, friction and windage losses

Friction and windage losses

No load core, friction and windage losses

Rotor core, friction and windage losses

Question 3 of 10

Question 4 of 10

4. The iron losses in a saturated three phase alternator is lesser than the non-saturated three phase alternator.

True

False

Question 4 of 10

Question 5 of 10

5. Synchronous-induction coupled motors are required for ____________

high pull out torque applications

high running torques applications

high starting torque applications

none of the mentioned

Question 5 of 10

Question 6 of 10

6. If one of the phases of the supply breaks down, then the connected three phase induction motor ____________

stops operating after few seconds

continues to run as single phase induction motor

continues to run as a single phase induction motor, provided load does does not increase beyond 57.7%

continues to run as two phase induction motor

Question 6 of 10

Question 7 of 10

7. The usual lamination thickness selected to minimize the eddy current loss in rotor is _____________

0.3 mm to 0.4 mm

0.4 mm to 0.5 mm

0.9 mm to 0.10 mm

0.1 mm to 0.2 mm

Question 7 of 10

Question 8 of 10

8. A duplex lap wound armature is used in six pole dc machine with six brush set. The number of current paths in this machine is?

Question 8 of 10

Question 9 of 10

9. A 3-phase synchronous alternator is connected to the infinite bus is over excited, that corresponds to ______________

capacitor

variable inductor

inductor

any of the mentioned

Question 9 of 10

Question 10 of 10

10. A peaky voltage supply is given to the 3 phase power transformer of the connection power system. These results in _________

reduction in noise

increase in iron losses

reduction in copper losses

reduction in iron losses

Question 10 of 10