By the use of which of the following, high frequency power supply for induction furnaces can be obtained?

Induction furnaces are employed for which of the following?

A

Heat treatment of castings

B

Heating of insulators

C

Melting aluminium

D

None of the above

A power supply which has voltage regulation of ___________ is unregulated power supply

A

0%

B

5%

C

10%

D

8%

Maximum heat transfer in high temperature furnaces is by

A

Conduction

B

Convection

C

Radiation

D

Either A, B or C; depends on the type of furnace

Direct arc furnaces have which of the following power factors?

A

Unity

B

Low, lagging

C

Low, leading

D

Any of the above

It is desirable to operate the arc furnaces at power factor of

A

Zero

B

0.707 lagging

C

Unity

D

0.707 leading

A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is

A

Slop speed operation

B

High starting torque

C

Low windage losses

D

All of the above

Fuel economy in furnaces can be achieved by

A

Using oxygen enriched combustion air

B

Preheating the combustion air

C

Reducing the heat loss through furnace openings & doors

D

All of the above

Thermal efficiency of furnaces can be improved by

A

Waste heat recovery from flue gas

B

Minimising heat losses from furnace walls

C

Maintaining proper draught

D

All of the above

The average mark obtained by 15 students was 10 and the average mark obtained by 10 students was 15. What was the average mark obtained by all students?

A

10

B

8

C

12

D

15

The average mark obtained by 10 students was 6 and the average mark obtained by 6 other students was 10. What was the average mark obtained by all 16 students?

A

10

B

8

C

7.5

D

8.5

By the use of which of the following, high frequency power supply for induction furnaces can be obtained?

Related Questions