1. What is the Pulley Speed Calculation Formula?

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

Purpose: It helps mechanics, engineers, and DIY enthusiasts design and troubleshoot belt-driven systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RPM2 \) — Output speed (revolutions per minute)
• \( RPM1 \) — Input speed (revolutions per minute)
• \( D1 \) — Diameter of drive pulley (inches)
• \( D2 \) — Diameter of driven pulley (inches)

Explanation: The speed ratio is inversely proportional to the pulley diameter ratio. A larger driven pulley will rotate slower than the drive pulley.

3. Importance of Pulley Speed Calculation

Details: Proper pulley speed calculation ensures optimal machine performance, prevents belt slippage, and helps achieve desired output speeds.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Does belt thickness affect the calculation?
A: For most applications, no. The calculation uses pitch diameters which account for belt thickness.

Q2: What if I have multiple pulleys in the system?
A: Calculate each stage sequentially, using the output RPM from one stage as the input for the next.

Q3: How accurate is this calculation?
A: It's theoretically accurate for ideal conditions. Real-world factors like belt slip may cause minor variations.

Q4: Can I use this for metric measurements?
A: Yes, as long as both diameters use the same units (e.g., both in mm or both in cm).

Q5: What's the relationship between pulley size and speed?
A: Larger pulleys rotate slower than smaller ones when connected by the same belt.