A. To avoid initial rush of current
B. To avoid change in kW rating with temperature
C. Both (A) and (B)
D. Either (A) or (B)
A. zero
B. 0.707 lagging
C. unity
D. 0.707 leading
It is desirable to operate the arc furnaces at power factor of_____________? Read More »
Heating and Welding A. it is filled below core level
B. it is filled above core level
C. it is fully empty
D. none of the above
Ajax Wyatt furnace is started when____________? Read More »
Heating and Welding A. T1
B. T2
C. T3
D. T*
Radiations from a black body are proportional to____________? Read More »
Heating and Welding A. Variation of resistance
B. Variation of voltage
C. Periodical switching on and off of the supply
D. All of the above methods
Which of the following methods is used to control temperature in resistance furnaces ? Read More »
Heating and Welding A. to stabilize the arc
B. to imprpve, power factor
C. to reduce severity of the surge
D. none of the above
In arc furnace the function of choke is______________? Read More »
Heating and Welding A. induction heating of steel
B. dielectric heating
C. induction heating of brass
D. resistance heating
Hysteresis loss and eddy current loss are used in____________? Read More »
Heating and Welding A. bad, good
B. bad, bad
C. good, bad
D. good, good
A. induced current flow through the charge
B. hysteresis loss taking place below curie temperature
C. due to hysteresis loss as well as eddy current loss takingplace in the charge
D. none of the above factors
A. series
B. parallel
C. series-parallel connections
D. star-delta connections
E. all of the above ways
