Answer / guest

Turbine shaft material has its own natural frequency, when
turbine rotates on such a speed that frequency of shaft
become close to its natural frequency, machine causes noise
& high vibrations because of resonance due to matching of
frequency. Running of Steam "TURBINE" on this speed is
avoided & this is called Critical speed. A turbine may have
more then one critical speed, which may depend upon number
of couplings.

it is denoted by w(omega).

Answer / guest

Turbine shaft material has its own natural frequency, when
turbine rotates on such a speed that frequency of shaft
become close to its natural frequency, machine causes noise
& high vibrations because of resonance due to matching of
frequency. Running of Steam "TURBINE" on this speed is
avoided & this is called Critical speed. A turbine may have
more then one critical speed, which may depend upon number
of couplings.

it is denoted by w(omega).

Answer / a.saravanan

it is the phase of speed at which the natural frequency of the turbine shaft matches with the frequency at the speed. during this period more vibration and noise will come. to avoid this,(in fact we can not avoid) acceleration will be increased so that less time to cross the critical speed. thanking you.

Answer / kuldeep thakur

Turbine shaft material has its own natural frequency, when
turbine rotates on such a speed that frequency of shaft
become close to its natural frequency, machine causes noise
& high vibrations because of resonance due to matching of
frequency. Running of Steam "TURBINE" on this speed is
avoided & this is called Critical speed. A turbine may have
more then one critical speed, which may depend upon number
of couplings.............

Answer / sunil

when the normal rpm of turbine coinside with the natural frequency of tranverse vibration of the shaft.at this the vibration tends to infinity and causes of deflection of shaft.

Answer / sornakumar

The angular speed of rotating machinery at which excessive vibration is produced; at this speed the periodic disturbing force coincides with a mechanical resonance of the shaft and/or of the machinery or its supports.this effect in turbine is called critical speed of turbine

Answer / p.v.k.phanindra

Critical speed of a turbine is defined as the speed at which vibrations will occur. Critical speed of a turbine is more than one that can be depend upon no of couplings

Answer / raja

actually the critical speed of turbine should not based
entirely on resonance effect....the critical speed is based
on the uniform speed of the generator .....and we ensured
this should not equal to natural frequeny

Answer / salah

The Critical Speed is The Speed at Which the Center of mass
Not Equal to The Center of Rotation

Answer / naresh puli

In witch speed turbine vibration is most
Violently,it is due to many causes such as
Imbalance or harmonic vibration set up by entire mechine

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