1. What is Belt Pulley Ratio?

The belt pulley ratio is the relationship between the diameters of the driver pulley (D1) and the driven pulley (D2). It determines the speed and torque transfer between the two pulleys in a belt drive system.

2. How Does the Calculator Work?

The calculator uses the simple ratio formula:

Where:

• \( D1 \) — Diameter of driver pulley (mm)
• \( D2 \) — Diameter of driven pulley (mm)

Explanation: The ratio directly compares the sizes of the two pulleys. A ratio greater than 1 means the driven pulley will rotate slower than the driver pulley, while a ratio less than 1 means it will rotate faster.

3. Importance of Pulley Ratio Calculation

Details: Calculating the pulley ratio is essential for designing belt drive systems to achieve desired speed and torque characteristics in machinery and automotive applications.

4. Using the Calculator

Tips: Enter both pulley diameters in millimeters. Both values must be positive numbers. The calculator will compute the ratio (dimensionless value).

5. Frequently Asked Questions (FAQ)

Q1: How does pulley ratio affect speed?
A: The speed ratio is inversely proportional to the pulley ratio. If the ratio is 2:1, the driven pulley will rotate at half the speed of the driver pulley.

Q2: What is a typical pulley ratio range?
A: Common ratios range from 1:3 to 3:1, but specific applications may require ratios outside this range.

Q3: Should I measure pulley diameter at the belt or groove?
A: For V-belts, measure the pitch diameter (at the belt's neutral axis). For flat belts, measure the outer diameter.

Q4: Does belt thickness affect the ratio?
A: Generally no, as both pulleys are affected equally by belt thickness in standard calculations.

Q5: Can I use this for timing belts?
A: Yes, but for timing belts you should use the number of teeth on each pulley for more precise ratio calculation.