A. to stabilize the arc
B. to imprpve, power factor
C. to reduce severity of the surge
D. none of the above
Related Mcqs:
- In direct arc furnace, which of the following has high value ?
A. Current
B. Voltage
C. Power factor
D. All of the above - The electrode of a direct arc furnace is made of____________?
A. tungsten
B. graphite
C. silver
D. copper - By which of the following methods the temperature inside arc nace can be varied ?
A. By disconnecting some of the heating elements
B. By varying the operating voltage
C. By varying the current through heating elements
D. By any of the above method - Due to which of the following reasons it is desirable to have short arc length ?
A. To achieve better heating
B. To increase the life of roof refractory
C. To have better stirring action
D. To reduce problem of oxidation
E. All of the above - 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 - The material of the heating element for a furnace should have___________?
A. lower melting point
B. higher temperature coefficient
C. high specific resistance
D. all of the above - In a resistance furnace the atmosphere is_____________?
A. oxidizing
B. deoxidising
C. reducing
D. neutral - Which of the following will happen if the thickness of refractory wall of furnace is increased ?
A. Heat loss through furnace wall will increase
B. Temperature inside the furnace will fall
C. Temperature on the outer surface of furnace walls will drop
D. Energy consumption will increase - The temperature inside a furnace is usually measured by which of the following ?
A. Optical pyrometer
B. Mercury thermometer
C. Alcohol thermometer
D. Any of the above
