1. What is a Critical Speed Calculator?

Definition: This calculator determines the critical speed of a rotating shaft, which is the speed at which the shaft becomes dynamically unstable.

Purpose: It helps mechanical engineers and designers ensure shafts operate below their critical speed to prevent resonance and failure.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( N_c \) — Critical speed (rpm)
• \( g \) — Acceleration due to gravity (9.81 m/s²)
• \( \delta \) — Static deflection of the shaft (meters)

Explanation: The formula relates the natural frequency of the shaft to its static deflection under gravity.

3. Importance of Critical Speed Calculation

Details: Operating above critical speed can cause catastrophic failure due to resonance. This calculation helps prevent such scenarios.

4. Using the Calculator

Tips: Enter gravity (default 9.81 m/s²) and the shaft's static deflection in meters. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What happens if a shaft operates at critical speed?
A: The shaft will experience resonance, leading to excessive vibrations and potential failure.

Q2: How is static deflection determined?
A: It's calculated based on shaft material, dimensions, and loading conditions using beam deflection formulas.

Q3: Should operating speed be above or below critical speed?
A: Typically below, though some designs safely operate above (supercritical shafts) with proper damping.

Q4: Does this consider multiple critical speeds?
A: No, this calculates only the first critical speed. Complex shafts have multiple critical speeds.

Q5: How accurate is this calculation?
A: It provides a basic estimate. More precise analysis requires detailed FEA or rotor dynamics software.