Skip to main content

Part -4 Most commonly asked Mechanical Interview Questions

Most commonly asked Mechanical Interview Questions with answer

1.          What is Difference between stamina and strength?

Ans.    Strength is capability over a short length of time and Stamina is the ability to keep going continuously.

2.          What is Hydro-static System?

Ans.    Hydrostatics is the study of fluid bodies that are
  • At rest
  • Moving sucient slowly so there is no relative motion between adjacent parts of the body
For hydrostatic situations
  • There are no shear stresses
  • There are only pressure forces that act perpendicular to any surface.
It’s a closed loop hydraulic systems. It comprises of motor and pump. Here pump supplies energy to motor and motor gives return energy to pump supply.

3.          What is Cotter joint?

Ans.     A cotter joint is used to connect rigidly two co-axial rods or bars which are subjected to axial tensile or compressive forces. Here shaft is locked in place by a smaller pin that passes through the side of the lug and partly or completely through the shaft itself. This locking pin is named as cotter.

4.          How is the excess discharge pressure prevented?

Ans.     Discharge pressure prevented by a pressurized spike cushion. Here the system employs a pressurized cushion of air and a two o-ring piston, which permanently separates this air cushion from the water system. When the valve closes and the water flow is suddenly stopped, the pressure spike pushes the piston up the arrester chamber against the pressurized cushion of air. The air cushion in the arrester reacts instantly, absorbing the pressure spike that causes water hammer.

5.          What is the difference between Strainer and Filter?

Ans.     Strainer for coarse size, Filter is more accurate than Strainer.

6.          What is the position of Piston Ring?

Ans.     In 180 degree angle the Top ring, Second ring and Oil ring are fixed. Position the ring approximately 1 inch gap below the neck.

7.          Why Deaerator are placed at Height, In Thermal Power Plant?

Ans.    To build a Very high pressure and the temperature for a boiler feed water pump and it discharge high pressure water to the boiler.
And to provide the required Net Positive Suction Head (NPSH) for the BFW pump and to serve as a storage tank to ensure a continuous supply of feed water during rapid changes in BFP.

8.          What is meant by One Tonn Air-Conditioner?

Ans.     1 ton refrigeration means 210 kJ/min extracts heat from the system.

9.          State 1st Law of Thermodynamics?

Ans.    Heat and mechanical work are mutually convertible. Energy can neither be created nor be destroyed but it can be transferred from one form to another.

10.          If you heat a steel pipe with the hole at centre, does heat affects the hole diameter?


Ans.     It gets bigger.

See related more FAQs  <<<< Click Here >>>>



Popular posts from this blog

Vickers Hardness Test

Vickers Hardness Test:- The Vickers hardness test method consists of indenting the test material with a diamond indenter, in the form of a right pyramid with a square base and an angle of 136 degrees between opposite faces subjected to a load of I to I 00 kgf. The full load is normally applied for I 0 to 15 seconds. The two diagonals of the indentation left in the surface of the material after removal of the load are measured using a microscope and their average calculated. The area of the sloping surface of the indentation is calculated. The Vickers hardness is the quotient obtained by dividing the kgf load by the square mm area of indentation. F= Load in kgf d = Arithmetic mean of the two diagonals, di and d2 in mm HV = Vickers hardness When the mean diagonal of the indentation has been determined the Vickers hardness may be calculated from the formula, but is more convenient to use conversion tables. The Vickers hardness should be reported like 800 HV/10, which means a Vickers...

Rockwell Hardness Test

Rockwell Hardness Test The Rockwell hardness test method consists of indenting the test material with a diamond cone or hardened steel ball indenter. The indenter is forced into the test material under a preliminary minor load FO usually I 0 kgf. When equilibrium has been reached, an indicating device, which follows the movements of the indenter and so responds to changes in depth of penetration of the indenter is set to a datum position. While the preliminary minor load is still applied an additional major load is applied with resulting increase in penetration . When equilibrium has again been reach, the additional major load is removed but the preliminary minor load is still maintained. Removal of the additional major load allows a partial recovery, so reducing the depth of penetration. The permanent increase in depth of penetration, resulting from the application and removal of the additional major load is used to calculate the Rockwell hardness number.        ...