Question 1

The power factor of a single-phase induction motor is usually

Accepted Answer

A)  lagging
B)  always leading
C)  unity
D)  unity to 0.8 leading A

Question 2

In A.C. series motor compensating winding is employed to

Accepted Answer

A)  reduce the effects of armature reaction
B)  increase the torque
C)  reduce sparking at the brushes
D)  none of the above C

Question 3

The wattage rating for a ceiling fan motor will be in the range

Accepted Answer

A)  200 to 250 W
B)  250 to 500 W
C)  50 to 150 W
D)  10 to 20 W C

Question 4

In case of a shaded pole motor the direction of rotation of the motor is

Accepted Answer

A)  from main pole to shaded pole
B)  from shaded pole to main pole
C)  either of the above depending on voltage
D)  either of the above depending on power factor

Question 5

The wattage of motor for driving domestic sewing machine will be around

Accepted Answer

A)  100 to 150 W
B)  40 to 75 W
C)  10 to 30 W
D)  5 to 10 W

Question 6

In split-phase motor iauxiliary winding is of

Accepted Answer

A)  thick wire placed at the bottom of the slots
B)  thick wire placed at the top of the slots
C)  thin wire placed at the top of the slots
D)  thin wire placed at the bottom of the slots

Question 7

For which of the applications a reluctance motor is preferred ?

Accepted Answer

A)  Electric shavers
B)  Refrigerators
C)  Signalling and timing devices
D)  Lifts and hoists

Question 8

A universal motor can run on

Accepted Answer

A)  A.C. only
B)  D.C. only
C)  either A.C. or D.C.
D)  none of the above

Question 9

Which of the following motors is preferred for tape-recorders ?

Accepted Answer

A)  Shaded pole motor
B)  Hysteresis motor
C)  Two value capacitor motor
D)  Universal motor

Question 10

Which of the following motors will operate at high power factor ?

Accepted Answer

A)  Shaped pole motor
B)  Split phase motor
C)  Capacitor start motor
D)  Capacitor run motor

Question 11

Which of the following motor will give the highest starting torque ?

Accepted Answer

A)  D.C. shunt motor
B)  Schrage motor
C)  Repulsion start and induction run motor
D)  Universal motor

Question 12

A hysteresis motor works on the principle of

Accepted Answer

A)  hysteresis loss
B)  magnetisation of rotor
C)  eddy current loss
D)  electromagnetic induction

Question 13

Which of the following single-phase induction motors is generally used in time phonographs ?

Accepted Answer

A)  Resistance start
B)  Capacitor start capacitor run
C)  Shaded pole
D)  Universal

Question 14

A schrage motor can run on

Accepted Answer

A)  zero slip
B)  negative slip
C)  positive slip
D)  all of the above

Question 15

The repulsion-start induction-run motor is used because of

Accepted Answer

A)  good power factor
B)  high efficiency
C)  minimum cost
D)  high starting torque

Question 16

In a two value capacitor motor, the capacitor used for running purposes is

Accepted Answer

A)  air capacitor
B)  paper spaced oilfilled type
C)  ceramic type
D)  a.c. electrolytic type

Question 17

The motor used on small lathes is usually

Accepted Answer

A)  universal motor
B)  D.C. shunt motor
C)  single-phase capacitor run motor
D)  3-phase synchronous motor

Question 18

A single-phase induction motor is

Accepted Answer

A)  inherently self-starting with high torque
B)  inherently self-starting with low torque
C)  inherently non-self-starting with low torque
D)  inherently non-self-starting with high torque

Question 19

Which of the following motors has highest starting torque ?

Accepted Answer

A)  Repulsion motor
B)  Shaped pole motor
C)  Capacitor-start motor
D)  Split-phase motor

Question 20

Single phase induction motor usually operates on

Accepted Answer

A)  0.6 power factor lagging
B)  0.8 power factor lagging
C)  0.8 power factor leading
D)  unity power factor

Exam 2: Motor Types and Applications