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RPM Formula:
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The RPM (Revolutions Per Minute) formula calculates rotational speed from power and torque. This fundamental mechanical engineering equation is widely used in automotive, industrial, and mechanical applications to determine engine or motor speed.
The calculator uses the RPM formula:
Where:
Explanation: The constant 5252 comes from the relationship between horsepower, torque, and RPM, where 1 horsepower equals 550 foot-pounds per second and there are 60 seconds in a minute.
Details: RPM calculation is essential for engine performance analysis, gear ratio selection, motor sizing, and understanding the power-torque relationship in rotational systems.
Tips: Enter power in horsepower, torque in pound-feet. Both values must be positive numbers. The calculator will compute the corresponding RPM.
Q1: Why is the constant 5252 used in the formula?
A: The constant 5252 comes from unit conversion: 1 hp = 550 ft-lb/s × 60 s/min ÷ 2π radians = 5252. It ensures proper unit relationships between horsepower, torque, and RPM.
Q2: What are typical RPM ranges for engines?
A: Car engines typically operate between 1000-7000 RPM, diesel engines 800-3500 RPM, and electric motors can range from 1000-20000 RPM depending on type.
Q3: Can this formula be used for metric units?
A: For metric units (kW and Nm), use RPM = (Power × 9549) ÷ Torque, where 9549 is the metric conversion constant.
Q4: What is the relationship between power and torque?
A: Power is the rate of doing work, while torque is rotational force. Power = (Torque × RPM) ÷ 5252 in imperial units.
Q5: When is RPM calculation most important?
A: RPM calculation is crucial for engine tuning, transmission design, performance optimization, and ensuring mechanical components operate within safe speed limits.