Motor Torque Calculation Formula

Motor Torque Equation:

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

Torque (T):

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1. What is the Motor Torque Formula?

The motor torque formula calculates the rotational force produced by an electric motor based on its power output and rotational speed. It's essential for selecting the right motor for mechanical applications.

2. How Does the Calculator Work?

The calculator uses the motor 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 formula shows that torque is inversely proportional to speed when power is constant. Higher speed means lower torque, and vice versa.

3. Importance of Torque Calculation

Details: Proper torque calculation ensures motors are correctly sized for their applications, preventing underpowered performance or wasteful oversizing. It's crucial for mechanical design, power transmission systems, and industrial machinery.

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

Q2: What are typical torque values for industrial motors?
A: Small motors might produce 1-10 Nm, while large industrial motors can produce thousands of Nm. The exact value depends on power and speed.

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

Q4: Can I use this for hydraulic or pneumatic motors?
A: Yes, the formula works for any rotational prime mover when you know the input power and output speed.

Q5: What if my power is in horsepower (HP)?
A: First convert HP to kW (1 HP ≈ 0.746 kW) or use the alternative formula: T = (P × 5252)/N where P is in HP.