Answer / bappaditya ghosal

critical speed of a shunt wound generator is that speed for
which the given shunt field resistance will represent
critical field resistance.

Answer / rahul

What will happen if turbine will run long time on critical
speed??

Answer / partha das

when the dynamic frequency of oscillation in coiniside with
the natural frequency of oscillation is called critical
speed.

Answer / vibhu

Can any tell me what is 1st, 2nd & 3rd critical speed of turbo-generator?

Answer / zikireya

Each shaft material has its own natural frequency, when
shaft 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. This is called Critical speed.

Answer / ravibala

stationary parts frequency and rotary parts frequency
matching point is critical speed

Answer / gaurav

Critical speed is the speed at which rotor's natural
frequency
(rotor speed) matches with its resonent frequency
(exicitation). Running of turbine on this speed would cause
bending or breakage of the shaft.

Answer / dilip mishra

CRITICAL SPEED OF A ROTATING SHAFT IS THE SPEED AT WHICH THE SHAFT STARTS TO VIBRATE VIOLENTLY IN THE TRANSVERSE DIRECTION. IT IS VERY DANGEROUS TO CONTINUE TO RUN THE SHAFT AT ITS CRITICAL SPEED. THE AMPLITUDE OF VIBRATION WILL BUILD UP TO SUCH A LEVEL THAT THE SYSTEM GET BREAK /MAY GO TO PICES.CRITICAL SPEED IS ALSO QUITE OFTEN GIVEN THE NAME WHIRLING SPEED OR WHIPPING SPEED.AT THIS CONDITION THE NATURAL FREQUENCY IS EQUAL TO SYSTEM FREQUENCY.

Answer / haris rajput

The speed of engine is the crankshaft speed which causes the crankshaft to vibrate at its natural frequency of torsional vibration. it is the speed which induces resonance. the consequence of resonance is to cause the crankshaft to vibrate in torsional mode with large amplitudes :)

Answer / acharya

apart from Frequency, speed of rotatng disc also limited
by the fact that tip speed cannot cross sonic speed, larger
discs/propelers, critical speed is determined by tip speed
also.

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