Deck 2: Motor Types and Applications

Question 1

In a capacitor start single-phase motor, when capacitor is replaced by a resistance

A)torque will increase
B)the motor will consume less power
C)motor will run in reverse direction
D)motor will continue to run in same direction

Answer 1

motor will continue to run in same direction

Question 2

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

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

Answer 2

lagging

Question 3

A shaded pole motor can be used for

A)toys
B)hair dryers
C)circulators
D)all of the above

Answer 3

all of the above

Question 4

A hysteresis motor works on the principle of

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

Question 5

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

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

Question 6

For which of the applications a reluctance motor is preferred ?

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

Question 7

The motor used on small lathes is usually

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

Question 8

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

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

Question 9

A single-phase induction motor is

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 10

A schrage motor can run on

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

Question 11

A universal motor can run on

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

Question 12

Which of the following single-phase motors is suitable for timing and control purposes ?

A)Reluctance motor
B)Series motor
C)Repulsion motor
D)Universal motor

Question 13

Single phase induction motor usually operates on

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

Question 14

In split-phase motor iauxiliary winding is of

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 15

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

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

Question 16

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

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

Question 17

Which of the following motors can be run on AC. as well as D.C. supply ?

A)Universal motor
B)Repulsion motor
C)Synchronous motor
D)Reluctance motor

Question 18

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

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

Question 19

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

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

Question 20

Which of the following motors has highest starting torque ?

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

Question 21

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

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

Question 22

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

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 23

In case of high speed universal motor which of the following needs more attention ?

A)End play
B)Air gap
C)Insulation in rotor
D)Balancing of rotor

Question 24

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

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

Question 25

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

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