Answer / phani

the speed at which the system frequency and the rotor
frequency are equal

Answer / srinu

Critical speed means where natural frequency is equal to
system frequency.

Answer / saurabh kumar

critical speed is the speed at which rotor natural frequency
(rotor speed) matches with its excitation frequency.
Running of turbine on this speed is avoided

Answer / nirmal vyas

When the rotational speed is equal to the numerical value
of the natural vibration then that speed is called critical
speed.

Answer / s. kalihari

critical spped of turbine means resonanced speed of
rotating speed of turbine & natural speed of turbine.
turbine have its own natural speed according to its weight
length & width type of its bearing. so it is different for
diff machine. when turbine is rolling then its speed is
matched with that speed then there is high vibration & high
noise. so we avoid to cross that spped very fastly.

Answer / karthick

the speed at which the shaft rotates about its mean
position i.e., equilibrium position then it is known as
critical speed.it can be determined from mass and stiffness
of the shaft

Answer / natig

In solid mechanics, in the field of rotordynamics, 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's natural frequency, the object
begins to resonate which dramatically increases systemic
vibration. The resulting resonance occurs regardless of
orientation.
When the rotational speed is equal to the numerical value
of the natural vibration then that speed is called critical
speed.
For a rotating shaft there is a speed at which, for any
small initial deflection, the centripetral force is equal
to the elastic restoring force. At this point the
deflection increases greatly and the shaft is said
to "whirl". Below and above this speed this effect is very
much reduced. This critical (whirling speed) is dependent
on the shaft dimensions, the shaft material and the shaft
loads. The critical speed is the same as the frequency of
traverse vibrations.

Answer / kamlesh patel

It is the speed of any substance at which natural frequency
concide with its frequency therefore high vibration at this
stage deflection comes to infinite.critical speed mainly
depend on mass and stiffness of the material.stiffness is
the intensive property of the material any particles may
have more than one critical speed.

Answer / prabu

the speed at which resonace occurs are is known as the
critical speed

Answer / fred moscicki

How about: Critical speed is when restoring force
(determined by shaft bend strength) = unbalance force
(force created by spinning mass wanting to spin in a
position where it rotates around its centroid)

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