Answer / ashok ghadge

Turbine shaft is having its natural own frequency and due
to passing of steam shaft got forced frequency, when these
frequencies match (At critical speed) the sinusidal waves
of vibrations match and vibration amplitude is equal to
addition of respective amplitude of two waves. This gives
large amplitude for vibrations to the shaft. In such
situation shaft may fail.
Adv. Such critical speeds should be imediately overtaken to
safeguard the shaft.

Answer / chaitanya pithawa

turbine shaft also have its own frequency,if the natural
frequency will meet this frequency,at that time resonance
will occur and maximum vibration will occur,this will create
more noise.so at this speed the chances of the breakdown or
failure is maximum.
at this speed maximum output can be get.this is a adv.

Answer / kishore338

the mass axis of shaft is away from the geometrical axis of
the shaft because of gravitational pul on mass of a shaft
that increases the transves forces on the shaft while
rotating and is max at some speed. at this speed vibration
of shqaft is more and is hazzardus for shaft blades as well
as to the bearings

Answer / mayank jansari

At critical speed the sinusidal waves
of vibrations match and vibration amplitude is equal to
addition of respective amplitude of two waves. This gives
large amplitude for vibrations to the shaft. In such
situation shaft may fail.
Advantage-due to critical speeds shaft reaches its higest
efficiency.

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