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HP to Torque Formula:
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The HP to Torque formula calculates the torque output of an engine based on its horsepower and rotational speed (RPM). This fundamental mechanical engineering equation helps determine the twisting force produced by an engine at a given speed.
The calculator uses the torque formula:
Where:
Explanation: The constant 5252 comes from the relationship between horsepower, torque, and RPM, where 1 horsepower is defined as 550 foot-pounds per second and there are 5252 radians per minute at 1 RPM.
Details: Torque calculation is essential for engine performance analysis, vehicle acceleration prediction, transmission design, and understanding the power characteristics of mechanical systems across different operating speeds.
Tips: Enter horsepower value (must be greater than 0) and RPM value (must be greater than 0). The calculator will compute the torque output in pound-feet (lb-ft) at the specified rotational speed.
Q1: Why is the constant 5252 used in this formula?
A: The constant 5252 comes from unit conversion where 1 HP = 550 ft-lb/s and there are 5252 radians per minute at 1 RPM, making the formula dimensionally consistent.
Q2: What's the difference between horsepower and torque?
A: Torque is the rotational force, while horsepower is the rate at which work is done. Horsepower = (Torque × RPM) / 5252.
Q3: At what RPM does horsepower equal torque?
A: Horsepower and torque values are numerically equal at 5252 RPM, which is why this RPM is often highlighted on dyno charts.
Q4: Can this formula be used for electric motors?
A: Yes, the formula applies to any rotating machinery, including electric motors, internal combustion engines, and turbines.
Q5: How accurate is this calculation for real-world applications?
A: The formula provides theoretical torque values. Actual torque may vary due to mechanical losses, efficiency factors, and measurement conditions.