Question 1

A motor of less than full load power rating can be used if the load is

Accepted Answer

A) continuous duty 
B) short time duty 
C) intermittent periodic duty 
D) none of these. 
A) continuous duty 
B) short time duty 
C) intermittent periodic duty 
D) none of these. B

Question 2

In case of contactors, the duty in which the main contacts remain closed for a period bearing a definition relation to the no-load periods, is known as

Accepted Answer

A) Standard duty 
B) Intermittent duty 
C) Temporary duty 
D) Un-interrupted duty. 
A) Standard duty 
B) Intermittent duty 
C) Temporary duty 
D) Un-interrupted duty. B

Question 3

Most commonly used ac motor is

Accepted Answer

A) Synchronous motor 
B) Slip ring induction motor 
C) Squirrel cage induction motor 
D) ac commutator induction motor. 
A) Synchronous motor 
B) Slip ring induction motor 
C) Squirrel cage induction motor 
D) ac commutator induction motor. C

Question 4

Regenerative braking mode can be achieved in which quadrant (V-I curve)?

Accepted Answer

A) Third 
B) Second 
C) Fourth 
D) First 
A) Third 
B) Second 
C) Fourth 
D) First

Question 5

The motor commonly used in computers and digital systems is

Accepted Answer

A) dc shunt motor 
B) Induction motor 
C) Stepper motor 
D) Synchronous motor. 
A) dc shunt motor 
B) Induction motor 
C) Stepper motor 
D) Synchronous motor.

Question 6

Rolling mills exhibit what type of load torque characteristics?

Accepted Answer

A) Constant torque characteristics 
B) Linearly rising torque characteristics 
C) Non-Linearly rising torque characteristics 
D) Non-Linearly decreasing torque characteristics 
A) Constant torque characteristics 
B) Linearly rising torque characteristics 
C) Non-Linearly rising torque characteristics 
D) Non-Linearly decreasing torque characteristics

Question 7

The cooling time constant is usually

Accepted Answer

A) equal to the heating time constant 
B) more than heating time constant 
C) none of these. 
D) all of the above 
A) equal to the heating time constant 
B) more than heating time constant 
C) none of these. 
D) all of the above

Question 8

Reverse motoring mode is available in fourth quadrant.

Accepted Answer

A) True 
B) False 
C) none 
D) all of the above 
A) True 
B) False 
C) none 
D) all of the above

Question 9

The equilibrium speed of a motor load system is obtained

Accepted Answer

A) when motor torque equals the load torque 
B) when motor torque is less than the load torque 
C) when motor torque is more than the load torque 
D) none of the these. 
A) when motor torque equals the load torque 
B) when motor torque is less than the load torque 
C) when motor torque is more than the load torque 
D) none of the these.

Question 10

A class I contactor should be mechanically sound to withstand

Accepted Answer

A) 0.05 million times 
B) 0.25 million times 
C) 1.2 million times 
D) 5.0 million times. 
A) 0.05 million times 
B) 0.25 million times 
C) 1.2 million times 
D) 5.0 million times.

Question 11

Boost converter is used to _________

Accepted Answer

A) Step down the voltage 
B) Step up the voltage 
C) Equalize the voltage 
D) Step up and step down the voltage 
A) Step down the voltage 
B) Step up the voltage 
C) Equalize the voltage 
D) Step up and step down the voltage

Question 12

Effect of friction torque is more pronounced

Accepted Answer

A) when the drive is running on full speed 
B) when the drive is being started 
C) when the drive is being stopped 
D) when the drive at half of its normal speed. 
A) when the drive is running on full speed 
B) when the drive is being started 
C) when the drive is being stopped 
D) when the drive at half of its normal speed.

Question 13

Pole changing method of speed control is used in

Accepted Answer

A) slip ring induction motor 
B) dc shunt motor 
C) dc series motor 
D) squirrel cage induction motor. 
A) slip ring induction motor 
B) dc shunt motor 
C) dc series motor 
D) squirrel cage induction motor.

Question 14

In case of contactors the ratio of the in service period to the entire period, expressed as a percentage is known as

Accepted Answer

A) duty 
B) load factor 
C) class of contact 
D) none of the above. 
A) duty 
B) load factor 
C) class of contact 
D) none of the above.

Question 15

What is the relationship between torque and speed in constant type loads?

Accepted Answer

A) Torque is independent of speed 
B) Torque linearly increases with increase in speed 
C) Torque non-linearly increases with an increase in speed 
D) Torque non-linearly decreases with an increase in speed 
A) Torque is independent of speed 
B) Torque linearly increases with increase in speed 
C) Torque non-linearly increases with an increase in speed 
D) Torque non-linearly decreases with an increase in speed

Question 16

Which of the following pair is used for frequency converters ?

Accepted Answer

A) Squirrel cage induction motor and synchronous motor 
B) Wound rotor induction motor and synchronous motor 
C) Wound rotor induction motor and squirrel cage induction motor 
A) Squirrel cage induction motor and synchronous motor 
B) Wound rotor induction motor and synchronous motor 
C) Wound rotor induction motor and squirrel cage induction motor

Question 17

Type-A chopper is used for obtaining which type of mode?

Accepted Answer

A) Motoring mode 
B) Regenerative braking mode 
C) Reverse motoring mode 
D) Reverse regenerative braking mode 
A) Motoring mode 
B) Regenerative braking mode 
C) Reverse motoring mode 
D) Reverse regenerative braking mode

Question 18

Belted wound rotor induction motors are preferred for

Accepted Answer

A) machine tools 
B) gyratory crushers 
C) belt conveyor 
D) water pumps. 
A) machine tools 
B) gyratory crushers 
C) belt conveyor 
D) water pumps.

Question 19

Which one is an example of variable loss?

Accepted Answer

A) Windage loss 
B) Hysteresis loss 
C) Armature copper loss 
D) Friction loss 
A) Windage loss 
B) Hysteresis loss 
C) Armature copper loss 
D) Friction loss

Question 20

To save the energy during braking

Accepted Answer

A) dynamic braking is used 
B) plugging is used 
C) regenerative braking is used 
D) mechanical braking is used. 
A) dynamic braking is used 
B) plugging is used 
C) regenerative braking is used 
D) mechanical braking is used.

A motor of less than full load power rating can be used if the load is

In case of contactors, the duty in which the main contacts remain closed for a period bearing a definition relation to the no-load periods, is known as

Most commonly used ac motor is

Regenerative braking mode can be achieved in which quadrant (V-I curve)?

The motor commonly used in computers and digital systems is

Rolling mills exhibit what type of load torque characteristics?

The cooling time constant is usually

Reverse motoring mode is available in fourth quadrant.

The equilibrium speed of a motor load system is obtained

A class I contactor should be mechanically sound to withstand

Boost converter is used to _________

Effect of friction torque is more pronounced

Pole changing method of speed control is used in

In case of contactors the ratio of the in service period to the entire period, expressed as a percentage is known as

What is the relationship between torque and speed in constant type loads?

Which of the following pair is used for frequency converters ?

Type-A chopper is used for obtaining which type of mode?

Belted wound rotor induction motors are preferred for

Which one is an example of variable loss?

To save the energy during braking

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Motor for Various Applications

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Exam 7: Contactors, Motors, and Load Torques

A motor of less than full load power rating can be used if the load is

In case of contactors, the duty in which the main contacts remain closed for a period bearing a definition relation to the no-load periods, is known as

Most commonly used ac motor is

Regenerative braking mode can be achieved in which quadrant (V-I curve)?

The motor commonly used in computers and digital systems is

Rolling mills exhibit what type of load torque characteristics?

The cooling time constant is usually

Reverse motoring mode is available in fourth quadrant.

The equilibrium speed of a motor load system is obtained

A class I contactor should be mechanically sound to withstand

Boost converter is used to _________

Effect of friction torque is more pronounced

Pole changing method of speed control is used in

In case of contactors the ratio of the in service period to the entire period, expressed as a percentage is known as

What is the relationship between torque and speed in constant type loads?

Which of the following pair is used for frequency converters ?

Type-A chopper is used for obtaining which type of mode?

Belted wound rotor induction motors are preferred for

Which one is an example of variable loss?

To save the energy during braking

Electric Motors: Selection, Types, and Applications

Motor Selection and Applications in Various Industries

Motor for Various Applications

Motor and Drive System

Motor and Crane Technology: Understanding the Different Types and Applications

Electric Motors and Drives: Exploring Speed, Control, and Efficiency

Electrical Drives and Components

Motors and Drives for Industrial Applications

Motor and Power Systems

Locomotives and Train Systems

Traction Systems and Locomotive Performance

Filters