Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 2

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 2

Week 2: Assignment 2

     This weld symbol is used when the welding machine is:

 Fixed

 Portable

 Automatic

 None of these

D

1 point

The flare-bevel groove can be represented as:

 

 

 

 

A

1 point

The symbol for seam welding:

 

 

 

 

D

1 point

If the total welding cycle time is 10 min, dwell time is 4 min and arcing time is 5 min, then duty cycle of welding machine as per the American standard is:

 65%

 50%

 75%

 80%

B

1 point

Duty cycle is the ratio of

 welding cycle time to melting time

 Welding cycle time to arcing time

 Arcing time to welding cycle time

 Melting time to welding cycle time

C

1 point

If the current at 100% duty cycle is 250 A, then what should be the required current for 50% duty cycle?

 335.55 A

 353.55 A

 300.65 A

 325.55 A

B

1 point

In Motor-generator set for arc welding which of the generator is readily used:

 Shunt type

 Differentially compound type

 Level compound type

 Series type

B

1 point

Arc discharge accounts for:

 Low current and medium voltage

 Low voltage and high current

 High voltage and very low current

 Low current and low voltage

B

1 point

The range of open circuit voltage (OCV) in case of rectifiers is in the range of:

 50-80 V

 70-90 V

 100-120 V

 30-50 V

A

1 point

In case of welding Aluminum using unequal dwell which of the following is kept generally:

 Electrode positive is more than electrode negative

 Electrode positive is less than electrode negative

 Electrode positive is equal to electrode negative

 None of these

B

1 point

If the open circuit voltage is 60 volt and the short circuit current is 20 amperes. Then determine the voltage required for welding if the current required during welding is 10 amperes:

 60 V

 30 V

 40 V

 20 V

B

1 point

In a linear arc welding process, the heat input per unit length is inversely proportional to

 Welding voltage

 Welding current

 Welding speed

 Duty cycle of the power source

C