Deck 4: Motor and Drive System

Question 1

In jaw crushers a motor has to often start against....... load

A)Heavy
B)Medium
C)Normal
D)Low

Answer 1

Heavy

Question 2

........has least range of speed control

A)Slip ring induction motor
B)Synchronous motor
C)DC shunt motor
D)Schrage motor

Answer 2

Synchronous motor

Question 3

In series motor which of the following methods can be used for changing the flux per pole?

A)Tapped field control
B)Diverter field control
C)Series-parallel control
D)Any of the above

Answer 3

Any of the above

Question 4

Which of the following alternatives will be cheaper ?

A)A 100 HP ac three phase motor
B)Four motors of 25 HP each
C)Five motors of 20 HP each
D)10 motors of 10 HP each

Question 5

By the use of which of the following DC can be obtained from AC?

A)Silicon diodes
B)Mercury arc rectifier
C)Motor generator set
D)Any of the above

Question 6

Besides a constant speed a synchronous rotor possesses which of the following advantages ?

A)Lower cost
B)Better efficiency
C)High power factor
D)All of the above

Question 7

Which of the following types of motor and enclosure is safest

A)Totally enclosed
B)Totally enclosed fan cooled
C)Open time
D)Semi closed

Question 8

Which feature while selecting a motor for centrifugal pump will be of least significance?

A)Starting characteristics
B)Operating speed
C)Horse power
D)Speed control

Question 9

Which part of a motor needs maximum attention for maintenance?

A)Frame
B)Bearing
C)Stator winding
D)Rotor winding

Question 10

While selecting an electric motor for a floor Mill, which electrical characteristics will be of least significance ?

A)Running characteristics
B)Starting characteristics
C)Efficiency
D)Breaking

Question 11

Which off the following motors is used for elevators?

A)Induction motor
B)Synchronous motor
C)Capacitor start single phase motor
D)Any of the above

Question 12

...........is preferred for synthetic fibre mails

A)Synchronous motor
B)Reluctance motor
C)Series motor
D)Shunt motor

Question 13

For derries and winches which of the following drives can be used ?

A)Pole changing squirrel cage motors
B)DC motors with word Leonard control
C)AC slip rings motors with a variable resistance
D)Any of the above

Question 14

In........ method of starting three phase induction motors the starting voltage is not reduced

A)Auto transformer
B)Star Delta
C)Slip ring
D)Any of the above

Question 15

For which off the following applications DC motors are still preferred?

A)High operation
B)Variable speed drive
C)High starting torque
D)Reversibility

Question 16

Rotor of the motor is usually supported on........... bearings

A)Ball or roller
B)Needle
C)Thrust
D)Bush

Question 17

.............method of starting a three phase induction motor needs six terminals

A)Resistance starting
B)Auto transformer
C)None of the above
D)Star delta

Question 18

In a paper mill where constant speed is required

A)Synchronous motors are preferred
B)AC motors are preferred
C)Individual drive is preferred
D)Group drive is preferred

Question 19

........is not a part of ball bearing

A)Inner race
B)Outer race
C)Cage
D)Bush

Question 20

A pony motor is used for the starting which of the following motors ?

A)Squirrel cage induction motor
B)Schrage motor
C)Synchronous motor
D)None of the above

Question 21

........ has relatively wider range of speed control

A)Synchronous motor
B)Slip ring induction motor
C)Squirrel case induction motor
D)DC shunt motor

Question 22

Heat control switches are used in

A)Transformers
B)Cooling ranges
C)Three phase induction motors
D)Single face

Question 23

An elevator Drive is required to operate in

A)One quadrant only
B)Two quadrants
C)Three quadrants
D)Four quadrants

Question 24

Belt conveyors offer ..........starting torque

A)High
B)Low
C)Medium
D)Zero

Question 25

While selecting a motor for air-conditioner the feature of utmost importance is

A)Type of enclosure
B)Type of bearing
C)Noise
D)Power transmission arrangement