1
GATE ME 1989
Subjective
+5
-0
An arc welding $$DC$$ power source has a linear power source characteristic with open circuit voltage $${V_O} = \,\,80$$ volts and short circuit current $${{\rm I}_S} = 1000amps.$$ The voltage-length characteristic of the arc is given by $$V=20+4L$$ volts where $$L$$ is the arc length in $$mm,$$ calculate the optimum length of arc for obtaining maximum arc power at welding. What voltage and current setting should be done on the power source for maximum arc power.
2
GATE ME 1989
MCQ (Single Correct Answer)
+1
-0.3
Crater wear always starts at some distance from the tool tip because at that point
A
cutting fluid does not penetrate
B
chip tool interface temp is maximum
C
normal stress on rake face is maximum
D
tool strength is minimu8m
3
GATE ME 1989
MCQ (Single Correct Answer)
+1
-0.3
The size of $$BLUE$$ in metal cutting increases with
A
very high speed
B
large uncut chip thickness
C
use of cutting fluid
D
increase in positive rake angle
4
GATE ME 1989
MCQ (Single Correct Answer)
+2
-0.6
In turning operation the feed rate could be doubled to increase the metal removal rate To keep the same level of surface finish, the nose radius of the tool has to be
A
Doubled
B
Halved
C
Multiplied by $$4$$ time
D
Kept unchanged.
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