Electrical Engineering Mcqs Practice Test

Question 1

In three-phase induction motors sometimes copper bars are placed deep in the rotor to___________?

Accepted Answer

A. improve starting torque

Question 2

Which is of the following data is required to draw the circle diagram for an induction motor ?

Accepted Answer

D. Block rotor test, no-load test and stator resistance test

Question 3

In case of 3-phase induction motors, plugging means__________?

Accepted Answer

D. interchanging two supply phases for quick stopping

Question 4

In a three-phase induction motor_______________?

Accepted Answer

D. iron losses in stator will be more than that in rotor

Question 5

Short-circuit test on an induction motor cannot be used to determine___________?

Accepted Answer

A. windage losses

Question 6

The starting torque of a 3-phase squirrel cage induction motor is____________?

Accepted Answer

B. 1.5 times the full load torque

Question 7

A 3-phase slip ring motor has____________?

Accepted Answer

B. wound rotor

Question 8

5 H.P., 50-Hz, 3-phase, 440 V, induction motors are available for the following r.p.m. Which motor will be the costliest ?

Accepted Answer

A. 730 r.p.m.

Question 9

A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen ? It will____________?

Accepted Answer

D. get heated and subsequently get damaged

Question 10

Which type of bearing is provided in small induction motors to support the rotor shaft ?

Accepted Answer

A. Ball bearings

Question 11

The speed characteristics of an induction motor closely resemble the speedload characteristics of which of the following machines?

Accepted Answer

B. D.C. shunt motor

Question 12

It is advisable to avoid line starting of induction motor and use starter because____________?

Accepted Answer

C. motor takes five to seven times its full load current

Question 13

If a 3-phase supply is given to the stator and rotor is short circuited rotor will move___________?

Accepted Answer

B. in the same direction as the direction of the field

Question 14

As load on an induction motor goes on increasing______________?

Accepted Answer

D. its power factor goes on increasing up to full load and then it falls again

Question 15

Slip ring motor is recommended where____________?

Accepted Answer

D. all above features are required

Question 16

In an induction motor the relationship between stator slots and rotor slots is that_____________?

Accepted Answer

C. stator slots are not exact multiple of rotor slots

Question 17

Low voltage at motor terminals is due to____________?

Accepted Answer

C. any one of the above

Question 18

A 3-phase induction motor delta connected is carrying too heavy load and one of its fuses blows out. Then the motor______________?

Accepted Answer

C. will stop and carry heavy current causing permanent damage to its winding

Question 19

A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor_______________?

Accepted Answer

A. will continue running burning its one phase

Question 20

Size of a high speed motor as compared to low speed motor for the same H.P. will be__________?

Accepted Answer

B. smaller