Latest Mechanical Engineering Interview Questions Part – 29
What is the difference between Critical speed & Whirling speed?
In Solid mechanics, in the field of rotor dynamics, the critical speed is the theoretical angular velocity which excites the natural frequency of a rotating object, such as a shaft, propeller or gear. As the speed of rotation approaches the objects natural frequency, the object begins to resonate which dramatically increases system vibration. The resulting resonance occurs regardless of orientation.
Whirling Speed is due to the unbalanced forces acting on a rotating shaft.
What is the significance of Torque(in N-m) given in the engine specification ?
It give the moment about any point or simple rotation.
What is the abbreviation of Welding rod 7018?
70=tensile strength 70000psi
1= welding position
In ultrasonic machining the tool is made of
High speed steel
Brass & Copper
What are the uses of Graphite electrode in various field.
Graphite electrode is used in EDM and in Battery cells. It is also used in electric arc furnaces to melt the steel .
When a 40 watt lamp is connected in series with a 100 Watts lamp across a 220 V supply which one glows brighter
100 watt lamp
40 watt lamp
Both will glow with equal brightness
It cannot be predicted
40 watt lamp
Difference between TIG & MIG welding
Tungsten inert gas welding-non consumable electrode
MIG-Metal inert gas welding-uses consumable electrode
Specific speed of turbine?
The specific speed is defined as the the speed of the geometric turbine which can produce unit power at unit head
Material of Aircraft turbine blade?
Ni, Cr, Al, Traces of C
Do you know epicyclic gear box? What are the practical application of epicyclic gear box?
Epicyclic gear box consists of sun gear planetary gears and an annular called ring gear. Different speed ratios are obtained by locking any one gear. If you lock any two gear, direct gear will be obtained mostly used in overdrives. Wrist watch is a practical application of epicyclic gear box
What do you mean by super critical above 500MW in Thermal power plant?
In super critical boiler means all the steam to converted in to superheated steam at outlet of boiler no need to sent
to super heater once again.