Horsepower hour

Published: December 22, 2006, 3:19 pm

Topics:

Energy (main) Units (main)

Definition

Horsepower-hour is a unit of energy or work equal to the work done by one horsepower in one hour. Horsepower is the unit of power in the English system of measurement. The SI unit of energy is the joule.

One joule = 3.73·10^-7horsepower-hour.

History

The term horsepower was coined by James Watt (1736-1819), the Scottish inventor and mechanical engineer renowned for his improvements of the steam engine. A horse, harnessed to an appropriate machine, can lift 550 pounds at the rate of 1 foot per second.

Conversions

1 horsepower-hour = 1.97·10⁶ foot-pound
1 horsepower-hour = 6.42·10² kilocalorie (thermal)
1 horsepower-hour = 2.55·10^s Btu (thermal)
1 horsepower-hour = 2.68·10⁶ joules
1 horsepower-hour = 0.746 kilowatt-hours
1 horsepower-hour = 2.68¹³ ergs
1 horsepower-hour = 1.67·10²⁵ electron-volts
1 horsepower-hour = 2.68·10¹³ dyne-centimeters

Further reading

• SI base units and SI derived units, the Physics Laboratory, National Institute of Standards and Technology
• Energy conversion tool at unitconversion.org

Citation

Cleveland, C. (2006). Horsepower hour. Retrieved from http://editors.eol.org/eoearth/wiki/horsepower_hour