1. What is a Motor Pulley Speed Calculator?

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

Purpose: It helps mechanics, engineers, and DIY enthusiasts properly size pulleys for belt-driven systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Speed}_2 \) — Output speed (rpm)
• \( \text{Speed}_1 \) — Input speed (rpm)
• \( D_1 \) — Drive pulley diameter (inches)
• \( D_2 \) — Driven pulley diameter (inches)

Explanation: The output speed is inversely proportional to the ratio of pulley diameters.

3. Importance of Pulley Speed Calculation

Details: Proper speed calculation ensures equipment operates at optimal RPM, prevents belt slippage, and maintains system efficiency.

4. Using the Calculator

Tips: Enter the motor speed (rpm), drive pulley diameter (inches), and driven pulley diameter (inches). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What if I know the desired output speed?
A: Rearrange the formula to solve for the needed pulley diameter: \( D_2 = D_1 \times (\text{Speed}_1 / \text{Speed}_2) \).

Q2: Does belt thickness affect the calculation?
A: For precision, measure pulley diameter at the belt's pitch line (middle of the belt), not the outer edge.

Q3: What about multiple pulley systems?
A: For multiple stages, calculate each step sequentially, using the output of one stage as the input for the next.

Q4: How does this relate to torque?
A: As speed decreases, torque increases proportionally (and vice versa), maintaining constant power.

Q5: What's a typical motor speed?
A: Common electric motors run at 1725 or 3450 rpm, but always check your motor's nameplate.