What is horsepower?

  • (noun): A unit of power equal to 746 watts.
    Synonyms: HP, H.P.


Horsepower (hp) is the name of several units of measurement of power, the rate at which work is done. The most common conversion factor, especially for electrical power, is 1 hp = 746 watts. The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses. It was later expanded to include the output power of other types of piston engines, as well as turbines, electric motors and other machinery. The definition of the unit varied between geographical regions. Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on January 1, 2010, the use of horsepower in the EU is only permitted as supplementary unit.

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Some articles on horsepower:

Luna (tugboat) - Specifications
... Displacement light ship 315 tons Engine horsepower 760 horsepower (570 kW) Motor horsepower 600 horsepower (450 kW) Top speed running free 13 knots (24 km/h 15 mph) Fuel capacity 4,000 US ...
Supermarine Sea King - Variants
... Powered by 160 horsepower (120 kW) Beardmore or 240 horsepower (180 kW) Siddeley Puma engine ... Powered by 300 horsepower (220 kW) Hispano engine ...
Twin City Tractors - Twin City 12-20 - Maximum Drawbar Horsepower Tests
... Gear...low Drawbar horsepower...18.43 Pull weight (pounds)...3,476 Speed (miles per hour ...
Saleen S281 - Variants - S-281
... utilized a naturally aspirated stock 4.6L 2V SOHC V8 engine rated at 220 horsepower (164 kW) ... When the New Edge Mustang first appeared in 1999, the horsepower rating increased to 285 (213 kW) due to various engine improvements ... cylinder in the engine – now rated at 335 horsepower (250 kW) ...