Torque Calculator for Motor Shaft

Torque Formula:

\[ Torque (Nm) = \frac{Power (kW) \times 9550}{RPM} \]

Torque:

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1. What is Motor Shaft Torque?

Torque is a rotational force that causes an object to rotate about an axis. In motors, it represents the twisting force that the motor shaft can deliver at a given speed. It's a crucial parameter for motor selection and mechanical design.

2. How Does the Calculator Work?

The calculator uses the torque formula:

\[ Torque (Nm) = \frac{Power (kW) \times 9550}{RPM} \]

Where:

\( Power \) — Motor power in kilowatts (kW)
\( RPM \) — Rotational speed in revolutions per minute
9550 — Conversion factor combining unit conversions and constants

Explanation: The formula shows that torque is inversely proportional to speed when power is constant. Higher RPM means lower torque for the same power output.

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 motor power in kW and rotational speed in RPM. Both values must be positive numbers (power > 0, RPM ≥ 1).

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 9550 used in the formula?
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 type. Small motors might produce fractions of Nm, while large industrial motors can produce thousands of Nm.

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 or accelerate heavy masses.

Q4: What if my power is in horsepower (HP)?
A: First convert HP to kW (1 HP ≈ 0.746 kW) before using this calculator, or use the formula: Torque (Nm) = (HP × 5252)/RPM.

Q5: Does this formula work for all motor types?
A: Yes, it applies to all rotating machinery, but actual torque may vary with motor efficiency, especially at different speeds for variable speed drives.