1. What is the Horsepower Formula?

The horsepower formula (HP = (T × RPM) / 5252) calculates power output from torque and rotational speed. This equation is fundamental in automotive and mechanical engineering to compare engine performance characteristics.

2. How Does the Calculator Work?

The calculator uses the horsepower formula:

Where:

• \( HP \) — Horsepower (hp)
• \( T \) — Torque (lb-ft)
• \( RPM \) — Rotations per minute
• 5252 — Conversion constant

Explanation: The constant 5252 comes from the relationship between rotational work and power, where 1 horsepower equals 550 foot-pounds per second.

3. Relationship Between HP and Torque

Details: Torque represents rotational force, while horsepower represents the rate at which work is done. The formula shows that for a given torque, horsepower increases with RPM. At 5252 RPM, horsepower and torque values are always equal due to the conversion constant.

4. Using the Calculator

Tips: Enter torque in pound-feet (lb-ft) and RPM values. Both values must be positive numbers. The calculator will compute the corresponding horsepower.

5. Frequently Asked Questions (FAQ)

Q1: Why is 5252 the magic number in the formula?
A: 5252 comes from the conversion between different units of measurement: 1 horsepower = 550 foot-pounds per second, and there are 2π radians in one revolution with 60 seconds in a minute.

Q2: Which is more important, horsepower or torque?
A: Both are important but measure different things. Torque determines acceleration force, while horsepower determines how quickly work can be done (top speed and sustained performance).

Q3: Can I use this formula for electric motors?
A: Yes, the formula works for any rotating machinery, including electric motors, though the torque characteristics may differ from internal combustion engines.

Q4: Why do horsepower and torque curves cross at 5252 RPM?
A: This is mathematically inherent in the formula. When RPM = 5252, HP = T × 5252 / 5252 = T, so the values are equal at that specific RPM.

Q5: How accurate is this calculation for real-world applications?
A: The formula provides theoretical mechanical horsepower. Actual delivered power may be less due to various efficiency losses in the drivetrain system.