Critical Speed of the Shaft

  • Thread starter Ballena Joseph
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In summary, for the critical speed of the shaft, it is important to include the weight of all members mounted on the shaft, such as gears and pulleys, in the calculation of forces acting on it. This is necessary for accurately determining the critical speed, particularly in regards to resonances. The formula for calculating critical speed also requires the inclusion of all mounted weights in the summations.
  • #1
Ballena Joseph
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For the critical speed of the shaft, should I include the weight of the members mounted on the shaft (gears, pulleys, etc.) with the forces acting on it?
 
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  • #2
Ballena Joseph said:
For the critical speed of the shaft, should I include the weight of the members mounted on the shaft (gears, pulleys, etc.) with the forces acting on it?

I wish you would be more explicit in your questions and give the context of what you are asking about.

Do you mean the critical speed as in resonances? Ihttps://en.wikipedia.org/wiki/Critical_speed

If so, then yes. Everything mounted on the shaft changes the natural frequency.
 
  • #3
anorlunda said:
I wish you would be more explicit in your questions and give the context of what you are asking about.

Do you mean the critical speed as in resonances? Ihttps://en.wikipedia.org/wiki/Critical_speed

If so, then yes. Everything mounted on the shaft changes the natural frequency.
Critical speed of the shaft with given deflection and weight. From the formula: nc = (30/π)(ΣWy/ΣWy2)½
 
  • #4
You most definitely need to include all the weights mounted on the shaft inthe summations. When the shaft whirls, they must move with it.
 
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1. What is the critical speed of a shaft?

The critical speed of a shaft is the rotational speed at which the shaft experiences resonance, causing it to vibrate and potentially fail.

2. Why is the critical speed of a shaft important?

The critical speed of a shaft is important because it helps determine the safe operating speed of a rotating system. If the shaft operates above its critical speed, it can lead to mechanical failure and potential safety hazards.

3. How is the critical speed of a shaft calculated?

The critical speed of a shaft is calculated using the formula: N = (C x g) / √(L x D), where N is the critical speed in revolutions per minute (rpm), C is a constant based on the shaft material, g is the acceleration due to gravity, L is the length of the shaft, and D is the shaft diameter.

4. What factors can affect the critical speed of a shaft?

The critical speed of a shaft can be affected by various factors such as the material and geometry of the shaft, the supports and bearings, and the speed at which the shaft is rotating.

5. How can the critical speed of a shaft be controlled?

The critical speed of a shaft can be controlled by adjusting the material and geometry of the shaft, using proper supports and bearings, and limiting the speed at which the shaft is rotating to stay below the critical speed.

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