Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!


Usefulnes of a process

Sponsored Links

Efficiency is the measure of "usefulness" of an operation, process or machine - and can be expressed on the generic form

μ = Wo / Wi    (1)


μ = efficiency

Wo = output from the operation - can be work, power, produced products ... 

Wi = input to the operation - can work, power, input products ...

Efficiency can be expressed as a percentage or as a per-unit decimal fraction of 1.

Example - Efficiency of an Electric Motor

The input power to an electric motor is 2000 W. The output power to the shaft is 1800 W. The efficiency of the motor can be calculated as

μ = (1800 W) / (2000 W)

  = 0.9

  = 90%

Example - Efficiency of a Wind Mill

The teoretical energy potential for a wind mill is 300 kWh at given conditions. The power produced is 70 kWh. The efficiency of the wind mill can be calculated as

μ = (70 kWh) / (300 kWh)

  = 0.23

  = 23%

Sponsored Links

Related Topics

Related Documents

Tag Search

  • en: efficiency
Sponsored Links

Search the Engineering ToolBox

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!

Translate this page to
About the Engineering ToolBox!


This page can be cited as

  • Engineering ToolBox, (2011). Efficiency. [online] Available at: [Accessed Day Mo. Year].

Modify access date.

Customize Ads in the ToolBox

Make ads more useful in Google Ad Settings .

. .


3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Scientific Online Calculator

Scientific Calculator

10 12

Sponsored Links