Related Questions

________ has the best damping properties.
A Diamond
B High speed steel
C Mild steel
D Cast iron
In the field controlled motor the entire damping comes from
A Armature resistance
B Back emf
C Motor friction and load
D Field resistance
If the poles lie in second quadrant, damping ratio is
A 1
B less than 1
C zero
D more than 1
If poles lie in first quadrant, damping ratio is
A 1
B More than 1
C less than 1
D Zero
Critical damping is a function of
A Mass and stiffness
B Mass and damping coefficient
C Mass and natural frequency
D Damping coefficient and natural frequency
If $$\frac{\omega }{{\omega {\text{n}}}}$$ is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
A 0°
B 90°
C 180°
D 360°
If $$\frac{\omega }{{\omega {\text{n}}}}$$ is very low for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
A 0°
B 90°
C 180°
D 360°
The disc of an instrument using eddy current damping should be of
A conducting and magnetic material
B non-conducting and magnetic material
C conducting and non-magnetic material
D none of the above
Which of the following properties a damping oil must possess ?
A Must be a good insulator
B Should be non-evaporating
C Should not have corrosive action upon the metal of the vane
D The viscosity of the oil should not change with the temperature
E All of the above
In order to increase the damping of a badly underdamped system which of following compensators may be used ?
A Phase-lead
B Phase-lag
C Both (A) and (B)
D Either (A) and (B)
E None of the above

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