Horsepower and Torque Formula

Horsepower Formula:

\[ HP = \frac{T \times RPM}{5252} \]

Horsepower (HP):

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1. What is the Horsepower and Torque Formula?

Definition: This formula calculates horsepower based on torque and engine speed (RPM).

Purpose: It helps automotive engineers, mechanics, and enthusiasts understand the relationship between torque and horsepower in engines.

2. How Does the Formula Work?

The formula is:

\[ HP = \frac{T \times RPM}{5252} \]

Where:

\( HP \) — Horsepower
\( T \) — Torque (pound-feet)
\( RPM \) — Revolutions per minute
5252 — Conversion constant (derived from the relationship between rotational speed and power)

Explanation: Horsepower is a measure of power that combines torque and rotational speed. The constant 5252 comes from the conversion between foot-pounds per minute and horsepower.

3. Importance of the Formula

Details: Understanding this relationship helps in engine tuning, performance analysis, and comparing different engines.

4. Using the Calculator

Tips: Enter the torque value in pound-feet and the engine speed in RPM. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is 5252 the magic number?
A: It's the RPM at which torque and horsepower values are equal (when using lb-ft for torque). This comes from the definition of horsepower (33,000 ft-lb/min) divided by 2π radians per revolution.

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

Q3: Can I use this for electric motors?
A: Yes, the formula applies to any rotating machinery, including electric motors.

Q4: What if I have metric units?
A: Convert Nm to lb-ft (1 Nm = 0.7376 lb-ft) before using the formula.

Q5: Why do horsepower and torque curves cross at 5252 RPM?
A: Because at this RPM, the numerical values of horsepower and torque (in lb-ft) are equal due to the constant in the formula.