Electric Motor Torque Calculator

Torque Formula:

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

Torque:

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1. What is Electric Motor Torque?

Torque is the rotational force produced by an electric motor. It's a crucial parameter that determines the motor's ability to perform work and overcome load resistance. The torque output varies with speed (RPM) and power input.

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, and vice versa.

3. Importance of Torque Calculation

Details: Knowing a motor's torque is essential for proper motor selection, ensuring it can handle the required mechanical load. It's critical in applications like conveyors, pumps, and machine tools where starting and running torque requirements differ.

4. Using the Calculator

Tips: Enter the motor's rated power in kW and its operating speed in RPM. Both values must be positive numbers. The calculator will compute the torque in Newton-meters (Nm).

5. Frequently Asked Questions (FAQ)

Q1: Why is 9550 used in the formula?
A: 9550 combines several conversion factors: 60 (seconds to minutes), 1000 (watts to kilowatts), and 2π (radians to revolutions), simplified to 60000/(2π) ≈ 9550.

Q2: What's the difference between starting torque and running torque?
A: Starting torque is the torque when the motor begins turning from rest (usually higher), while running torque is during normal operation at rated speed.

Q3: How does voltage affect torque?
A: For AC induction motors, torque is proportional to the square of the voltage. A 10% voltage drop results in about 19% torque reduction.

Q4: What is the torque-speed curve?
A: It's a graph showing how torque varies with speed for a particular motor, typically highest at zero speed (locked-rotor torque) and decreasing as speed increases.

Q5: Can I use this for hydraulic motors?
A: The basic principle is similar, but hydraulic motors have additional factors like displacement and pressure that affect torque calculation.