Alternator Torque Calculator

Calculate the torque requirements for alternators based on RPM, power output, and efficiency

Input Parameters

Calculation Results

Calculation Formula

Torque (Nm) = (Power × 9549) / (RPM × Efficiency)

Where:
Torque - Rotational force produced by the alternator
Power - Electrical power output in kilowatts
RPM - Revolutions per minute of the alternator
Efficiency - Mechanical to electrical efficiency as percentage

Alternator Torque Calculator Calculator Usage Guide

Learn how to use the Alternator Torque Calculator and its working principles

How to Use This Calculator

  1. Enter the RPM (Revolutions Per Minute) of your alternator. This is typically the engine RPM multiplied by the gear ratio to the alternator.
  2. Input the power output of the alternator in kilowatts (kW).
  3. Specify the efficiency of the alternator as a percentage. A typical efficiency for automotive alternators ranges from 70-90%.
  4. Click the "Calculate" button to compute the torque and power density.

Understanding the Results

The calculator provides two key outputs:

  • Torque (Nm): This measures the rotational force required to operate the alternator at the specified RPM and power output.
  • Power Density (kW/kg): This indicates how efficiently the alternator converts mechanical energy to electrical energy relative to its weight.

Applications

This calculator is useful for:

  • Engineers designing vehicle electrical systems
  • DIY mechanics upgrading vehicle electrical systems
  • Students studying automotive engineering principles

Important Notes

For accurate results, ensure you're using the correct values for your specific alternator. The power density calculation assumes a standard 20kg alternator weight - this value may vary by manufacturer and model.