The Engineering ToolBox Web Google

Power and Horsepower in Electrical Motors

Electrical power is rated in Horsepower or Watts

Sponsored Links

Electrical power is in general rated in Watts or Horsepower. A horsepower is a unit of power equal to 746 watts or 33,000 lb.ft per minute (or 550 lb.ft per second).

A watt is a unit of measure equal to the power produced by a current of 1 amp across the potential difference of 1 volt. A watt is 1/746 of 1 horsepower.

Even if the watt is the base unit of electrical power, its common to rate motor power in either horsepower or watts.

Power in Watts

Electric power of a motor can be expressed as:

Pw = ηm U I         (1)

where

Pw = power (W, watt)

ηm = motor efficiency

U = voltage (V)

I = current (A, amps)

Power in Horsepower

Horse power of a motor can be expressed as:

Php = Pw / 746         (2)

or

Php = ηm U I / 746         (2b)

where

Php = horsepower (hp)

Example - The Horsepower of an Electrical Motor

The horse power of an 230 V electrical motor with 85% efficiency pulling 10 amps can be calculated as:

Php = 0.85 (230 V) (10 amps) / 746

    = 2.62 hp

Standard Horsepower Ratings

Standard horsepower ratings of electrical motors - 1 to 4000 hp are indicated below:

Sponsored Links

Related Topics

  • Electrical Amps and electrical wiring, AWG - wire gauge, electrical formulas, motors and units

Related Documents

Sponsored Links



Engineering ToolBox - SketchUp Edition - Online 3D modeling!

Engineering ToolBox - SketchUp Edition - enabled for use with the amazing, fun and free Google SketchUp.


Search the ToolBox

Google
Web The Engineering ToolBox

© The Engineering ToolBox 2005

9 12 8

handheld Engineering ToolBox - optimized for mobile devices! 3D Engineering ToolBox - draw and model technical applications!


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

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