Question 1

Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have more no load current?

Accepted Answer

A)  a
B)  b
C)  both a and b
D)  neither a nor b A

Question 2

Which gas defect is caused by hydrogen in molten metal?

Accepted Answer

A)  blow holes
B)  air inclusions
C)  open blows
D)  pin hole porosity D

Question 3

How much time (in a minute) is usually required for the passing of CO2 through the mould?

Accepted Answer

A)  one
B)  two
C)  five
D)  seven A

Question 4

During melting process flux is added to react with impurities to form?

Accepted Answer

A)  cavity
B)  slag
C)  cold shut
D)  blow holes

Question 5

Which of the following defect is not a gas defect?

Accepted Answer

A)  blow holes
B)  air inclusions
C)  run out
D)  pin hole porosity

Question 6

CO2 moulding process is an ideal process, where speed and flexibility is the prime requirement.

Accepted Answer

A) True 
 B)False

Question 7

Defects caused by the chilling of the casting are known as?

Accepted Answer

A)  hot spots
B)  hot tears
C)  shrinkage cavity
D)  swell

Question 8

Cuts, washes, swell, drop etc. are the examples of which of the following casting defects?

Accepted Answer

A)  gas defect
B)  pouring material defect
C)  moulding material defect
D)  metallurgical defect

Question 9

The direction of rmf when a three phase supply is given to stator of three phase induction motor is?

Accepted Answer

A)  zero
B)  ns
C)  2ns
D)  -ns

Question 10

Moisture from the mould can be removed by using of dryer or heater in CO2 moulding.

Accepted Answer

A) True 
 B)False

Question 11

Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have poorer power factor?

Accepted Answer

A)  a
B)  b
C)  both a and b
D)  neither a nor b

Question 12

Which of the following additives are added to the sand in CO2 moulding for the improvement in collapsibility of the sand?

Accepted Answer

A)  copper oxide
B)  wood flour
C)  aluminium oxide
D)  oil

Question 13

It is very safe to use CO2 in CO2 moulding, so it eliminates the use of any shielding apparatus.

Accepted Answer

A) True 
 B)False

Question 14

A three phase induction motor is sometimes calles a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is equal to stator frequency?

Accepted Answer

A)  it will not operate
B)  it will operate as induction motor only
C)  it will operate as induction generator
D)  it will operate in braking mode

Question 15

The lower fluidity of molten material causes_______________

Accepted Answer

A)  misrun
B)  cold shut
C)  misrun & cold shut
D)  fusion

Question 16

When the molten metal leaks out of mould which defect occurs?

Accepted Answer

A)  run out
B)  misrun
C)  fusion
D)  drop

Question 17

The speed of rotation is almost double in semi centrifugal casting as compared to the true centrifugal casting.

Accepted Answer

A) True 
 B)False

Question 18

Defect which occurs due to the solidification of casting is known as?

Accepted Answer

A)  swell
B)  misrun
C)  metal penetration
D)  shrinkage cavity

Question 19

How much percentage of sodium silicate (Na2SiO3) is added to the sand mixture in CO2 moulding?

Accepted Answer

A)  0 to 2 %
B)  2 to 6 %
C)  6 to 10 %
D)  10 to 14 %

Question 20

In centrifugal casting, a movable pouring basin is employed for the pouring of molten metal.

Accepted Answer

A) True 
 B)False

Exam 3: Casting Processes and Three Phase Induction Motors

Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have more no load current?

Which gas defect is caused by hydrogen in molten metal?

How much time (in a minute) is usually required for the passing of CO₂ through the mould?

During melting process flux is added to react with impurities to form?

Which of the following defect is not a gas defect?

CO₂ moulding process is an ideal process, where speed and flexibility is the prime requirement.

Defects caused by the chilling of the casting are known as?

Cuts, washes, swell, drop etc. are the examples of which of the following casting defects?

The direction of rmf when a three phase supply is given to stator of three phase induction motor is?

Moisture from the mould can be removed by using of dryer or heater in CO₂ moulding.

Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have poorer power factor?

Which of the following additives are added to the sand in CO₂ moulding for the improvement in collapsibility of the sand?

It is very safe to use CO₂ in CO₂ moulding, so it eliminates the use of any shielding apparatus.

A three phase induction motor is sometimes calles a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is equal to stator frequency?

The lower fluidity of molten material causes_______________

When the molten metal leaks out of mould which defect occurs?

The speed of rotation is almost double in semi centrifugal casting as compared to the true centrifugal casting.

Defect which occurs due to the solidification of casting is known as?

How much percentage of sodium silicate (Na2SiO3) is added to the sand mixture in CO₂ moulding?

In centrifugal casting, a movable pouring basin is employed for the pouring of molten metal.