How To Calculate Electric Motor Torque

Electric Motor Torque Formula:

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

Torque (T):

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1. What is Electric Motor Torque?

Electric motor torque is the rotational force produced by an electric motor. It represents the motor's ability to perform work and is a crucial parameter in motor selection and application design.

2. How Does the Calculator Work?

The calculator uses the torque formula:

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

Where:

\( T \) — Torque (lb-ft)
\( P \) — Power (HP)
\( RPM \) — Rotational speed (revolutions per minute)
\( 5252 \) — Conversion constant

Explanation: The constant 5252 comes from the conversion between horsepower and foot-pounds per minute, where 1 HP = 33,000 ft-lb/min and 5252 = 33,000 ÷ (2π).

3. Importance of Torque Calculation

Details: Accurate torque calculation is essential for proper motor sizing, ensuring the motor can handle the required load without stalling or overheating, and for designing mechanical systems that rely on specific torque values.

4. Using the Calculator

Tips: Enter power in horsepower (HP) and rotational speed in RPM (revolutions per minute). Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 5252 used in the formula?
A: The constant 5252 comes from the conversion between horsepower and foot-pounds per minute, where 1 HP = 33,000 ft-lb/min and 5252 = 33,000 ÷ (2π).

Q2: What is the difference between starting torque and running torque?
A: Starting torque is the torque produced when the motor begins rotating from standstill, while running torque is the torque produced during normal operation at specified RPM.

Q3: How does torque relate to motor power?
A: Torque and power are directly related through rotational speed. For the same power, higher RPM means lower torque, and vice versa.

Q4: What factors affect electric motor torque?
A: Motor design, voltage supply, current, magnetic field strength, and motor efficiency all affect the torque output of an electric motor.

Q5: When is high torque important in motor selection?
A: High torque is crucial for applications requiring high starting loads, such as conveyor systems, crushers, compressors, and heavy machinery that need to overcome inertia.