Question 1

A wound rotor induction motor is preferred over squirrel cage induction motor when the major consideration involved is

Accepted Answer

Wound rotor induction motors are preferred over squirrel cage motors when there is a need for high starting torque, low starting current, and speed control over a limited range. They allow for external resistance to be added to the rotor circuit, enabling these characteristics.

Question 2

When smooth and precise speed control over a wide range is desired, the motor preferred is

Accepted Answer

DC motors are preferred for applications requiring smooth and precise speed control over a wide range because their speed can be easily controlled by varying the supply voltage or through field winding variations.

Question 3

When quick speed reversal is a consideration, the motor preferred is

Accepted Answer

DC motors are preferred for applications requiring quick speed reversal due to their ability to change direction quickly and efficiently by simply reversing the current flow through the motor. This characteristic makes them ideal for tasks that require rapid changes in direction.

Question 4

Stator voltage control for speed control of induction motors is suitable for

Accepted Answer

Stator voltage control is suitable for fan and pump drives because these applications typically involve variable torque requirements that decrease with speed, making them well-suited for the characteristics of stator voltage control methods. This method is not efficient or suitable for applications requiring constant torque or high starting torque, such as cranes or constant load drives, nor is it used for running an induction motor as a generator.

Question 5

The selection of control gear for a particular application is based on the consideration of

Accepted Answer

The selection of control gear for a particular application considers all these factors: duty, starting torque, and limitations on starting current, to ensure optimal performance and compatibility with the application's requirements.

Question 6

As compared to squirrel cage induction motor, a wound rotor induction motor is preferred when the major consideration is

Accepted Answer

A wound rotor induction motor is preferred for applications requiring high starting torque because it allows for external resistance to be added to the rotor circuit, improving torque and controlling starting current.

Question 7

A synchronous motor is found to be more economical when the load is above

Accepted Answer

The answer of A synchronous motor is found to be...

Question 8

The advantage of a synchronous motor in addition to its constant speed is

Accepted Answer

Synchronous motors can operate at a high power factor, which is an advantage in terms of reducing power losses and improving the efficiency of the power system.

Question 9

In motor circuit static frequency changers are used for

Accepted Answer

Static frequency changers are primarily used for speed regulation in motor circuits by altering the frequency of the power supply, which directly affects the speed of AC motors.

Question 10

In case of traveling cranes, the motor preferred for boom hoist is

Accepted Answer

The answer of In case of traveling cranes, the motor...

Question 11

The characteristics of drive for. crane hoisting and lowering is

Accepted Answer

A crane hoisting and lowering drive requires smooth movement, precise control, and fast speed control to ensure safe and efficient operation.

Question 12

The capacity of a crane is expressed in terms of

Accepted Answer

The capacity of a crane is typically expressed in terms of tonnes, indicating the maximum weight the crane can safely lift.

Question 13

The traveling speed of cranes varies from

Accepted Answer

The typical traveling speed of cranes, especially overhead or gantry cranes used in industrial environments, ranges from 1 to 2.5 meters per second. This speed allows for safe and controlled movement of heavy loads.

Question 14

In overhead traveling cranes

Accepted Answer

Short time rated motors are preferred for overhead traveling cranes because they are designed for operations that require high power for short durations, which is typical for crane operations.

Question 15

15 minute rated motors are suitable for

Accepted Answer

15 minute rated motors are typically used for light duty applications, such as light duty cranes, where the motor is not required to run continuously and can cool down between operations.

Question 16

Light duty cranes are generally used in

Accepted Answer

Light duty cranes are versatile and can be used in various settings, including automobile workshops, pumping stations, and power houses, for tasks that require lifting lighter loads.

Question 17

Heavy duty cranes are used in

Accepted Answer

Heavy duty cranes are versatile and used in various industries, including heavy engineering workshops, steel plants, and ore handling plants, to lift and move heavy materials efficiently.

Question 18

1/2 hour rated motors are used for

Accepted Answer

The answer of 1/2 hour rated motors are used for
...

Question 19

Which of the following drive can be used for derricks and winches ?

Accepted Answer

The answer of Which of the following drive can be...

Question 20

The number of sets used in pole changing type squirrel cage motors for derricks and winches, is

Accepted Answer

The answer of The number of sets used in pole...

Quiz 9: Motors and Drives for Industrial Applications