Electric Motor Torque Calculator

Torque Equation:

\[ T = \frac{P \times 9550}{N} \]

Torque (T):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Torque Equation?

The torque equation calculates the rotational force produced by an electric motor based on its power output and rotational speed. It's fundamental for motor selection and mechanical system design.

2. How Does the Calculator Work?

The calculator uses the torque equation:

\[ T = \frac{P \times 9550}{N} \]

Where:

\( T \) — Torque in Newton-meters (Nm)
\( P \) — Power in kilowatts (kW)
\( N \) — Rotational speed in revolutions per minute (RPM)
9550 — Conversion factor combining unit conversions and constants

Explanation: The equation shows that torque is inversely proportional to speed when power is constant - as speed increases, torque decreases, and vice versa.

3. Importance of Torque Calculation

Details: Accurate torque calculation is essential for selecting appropriate motors, designing mechanical systems, ensuring proper power transmission, and preventing mechanical failures.

4. Using the Calculator

Tips: Enter power in kW and speed in RPM. Both values must be positive numbers. The calculator will compute the torque in Nm.

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 9550 used in the equation?
A: It combines the conversion factors between kW to W (1000), minutes to seconds (60), and radians to revolutions (2π) into one constant (60000/2π ≈ 9550).

Q2: What are typical torque values for electric motors?
A: Torque varies greatly by motor size and application - from fractional Nm for small motors to thousands of Nm for large industrial motors.

Q3: How does torque relate to motor performance?
A: Torque determines the motor's ability to overcome load resistance. Higher torque means better ability to start under load and handle variable loads.

Q4: Can this be used for AC and DC motors?
A: Yes, the equation applies to all electric motors when you know the power and speed. However, actual torque may vary with motor type under different operating conditions.

Q5: How does torque change with speed in real motors?
A: While this equation shows ideal conditions, real motors have torque-speed curves where torque may vary non-linearly with speed, especially at startup.