1. What is the Torque Equation from HP and RPM?

Definition: This calculator computes torque in pound-feet (lb-ft) using horsepower (HP) and revolutions per minute (RPM).

Purpose: Essential for mechanical engineers, automotive technicians, and anyone working with rotational systems to understand engine or motor performance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( T \) — Torque (lb-ft)
• \( HP \) — Horsepower
• \( RPM \) — Revolutions per minute
• 5252 — Conversion constant (derived from the relationship between HP, torque, and RPM)

Explanation: The formula shows that torque is directly proportional to horsepower and inversely proportional to RPM. The constant 5252 comes from the fact that 1 HP equals 550 ft-lb/s and there are 60 seconds in a minute.

3. Importance of Torque Calculation

Details: Torque measures rotational force and is crucial for understanding engine performance, gear ratios, and vehicle acceleration characteristics.

4. Using the Calculator

Tips: Enter the horsepower and RPM values. Both must be greater than zero. The result shows torque in pound-feet (lb-ft).

5. Frequently Asked Questions (FAQ)

Q1: Why is 5252 a special number in this equation?
A: At 5252 RPM, horsepower and torque values are always equal (when using lb-ft units) due to the conversion between rotational and linear work.

Q2: What's the difference between torque and horsepower?
A: Torque measures rotational force, while horsepower measures the rate at which work is done (torque × RPM).

Q3: Can I use this for electric motors?
A: Yes, the formula applies to any rotational power system, including electric motors, engines, and turbines.

Q4: What if my RPM is zero?
A: The equation becomes undefined at zero RPM. Torque at stall (0 RPM) must be measured directly.

Q5: How do I convert lb-ft to Nm?
A: Multiply lb-ft by 1.35582 to get Newton-meters (Nm).