Question { 3433 }

what is critical speed?

Answer

critical speed is the
theoretical angular
velocity that excites the
natural frequency of a
rotating object, such as a
shaft, propeller,
leadscrew, or gear.

Question { RRB, 3133 }

Purpose of condenser in refrigeration system?

Answer

condenser is a heat-
exchange device in a
refrigeration system;
consists of a vessel or
arrangement of pipes or
tubing in which refrigerant
vapor is liquefied
(condensed) by the removal
of heat.

Question { L&T, 49404 }

wt is the difference between clutch and brake?

Answer

Typical uses are to provide
adjustable tension for
unwinding webs (paper,
wire, film, etc.), and also
to provide an adjustable
torque load to a motor
under test (typically
stepper or gear motors).
Typical uses are to provide
adjustable tension for
rewinding webs, and
precision torque limiting
(tightening fasteners &
bottle caps)

Question { 3516 }

wt is powder coating ?wt r the guages used to check powder
coating ?

Answer

DeFelsko manufactures
instruments that measure
the thickness of powder
coatings on a variety of
substrates before or
after cure.

Question { Bosch, 9675 }

what is the minimum gear
ratio?

Answer

it should be 1:1.

Question { MPSC, 4401 }

what is the significance of
partial derivatives.

Answer

A partial derivative
basically tells you how a
function changes if I
change just one of many
variables it may depend on,
while keeping all other
variables constant.

On the other hand, a total
derivative tells you the
"TOTAL" information about
the function. It describes
how a function changes if
all (or some) variables are
changed together.

When a function depends
only on one variable then
ALL = one variable. In this
case, a partial derivative
is the same as the total
derivative

Question { 4944 }

What is meant by stages in
turbine....what is there
purpose....????

Answer

urbine blades are arranged
in multiple stages in
series, called compounding,
which greatly improves
efficiency at low speeds. A
reaction stage is a row of
fixed nozzles followed by a
row of moving nozzles.
Multiple reaction stages
divide the pressure drop
between the steam inlet and
exhaust into numerous small
drops, resulting in a
pressure-compounded
turbine. Impulse stages may
be either pressure-
compounded, velocity-
compounded, or pressure-
velocity compounded. A
pressure-compounded impulse
stage is a row of fixed
nozzles followed by a row
of moving blades, with
multiple stages for
compounding. This is also
known as a Rateau turbine,
after its inventor. A
velocity-compounded impulse
stage (invented by Curtis
and also called a "Curtis
wheel") is a row of fixed
nozzles followed by two or
more rows of moving blades
alternating with rows of
fixed blades. This divides
the velocity drop across
the stage into several
smaller drops. A series of
velocity-compounded impulse
stages is called a pressure-
velocity compounded turbine.

Question { 12035 }

Advantage of hollow shaft over the solid shaft

Answer

it provides less torsonal
stresses

Question { 5927 }

minimum ohm for lighting
minimum ohm for Earthing

Answer

25 ohms