1. What is a Drive Pulley Speed Calculator?

Definition: This calculator determines the output RPM of a driven pulley based on the input RPM and the diameters of both pulleys.

Purpose: It helps mechanical engineers, technicians, and DIYers design and troubleshoot belt-driven systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RPM2 \) — Output RPM of driven pulley
• \( RPM1 \) — Input RPM of drive pulley
• \( D1 \) — Diameter of drive pulley (inches)
• \( D2 \) — Diameter of driven pulley (inches)

Explanation: The speed ratio between pulleys is inversely proportional to their diameter ratio.

3. Importance of Pulley Speed Calculation

Details: Proper speed calculation ensures optimal machine performance, prevents belt slippage, and helps select appropriate pulley sizes.

4. Using the Calculator

Tips: Enter the drive pulley RPM, drive pulley diameter, and driven pulley diameter. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What if my pulleys are the same size?
A: If D1 = D2, then RPM2 = RPM1 (no speed change).

Q2: How does belt thickness affect the calculation?
A: For precision, use the pitch diameter (center of belt thickness) rather than outer diameter.

Q3: Can I use this for multiple pulley systems?
A: For multiple stages, calculate each pair sequentially.

Q4: What about belt slippage?
A: This assumes 100% efficiency. Actual RPM may be 1-3% lower due to slippage.

Q5: Does this work for chain drives?
A: Yes, but use sprocket tooth counts instead of diameters for chain drives.