Horsepower

Article

May 28, 2022

Horsepower (KM) - a power unit in the MKS system, outside the SI system. 1 HP 75 kgfm / s 735.49875 W 0.9863 HP A unit created in the 19th century in Germany, modeled on the steam horse (HP) used in Anglo-Saxon countries to compare the power of steam engines with a horse. A 3 HP steam engine can deliver approximately the power of 1 working horse. The factor of 3/1 comes from the fact that the 3 HP engine could replace 3 horses working all day in shifts every 8 hours and this description of the engine power was to facilitate calculations by investors who wanted to replace horses with a steam engine. Thus, 3 HP is the gross power given by 1 horse without losses. The German abbreviation PS (Pferdestärke) is also used. Replaced by watt after the introduction of the SI system. Still often used to determine the power of internal combustion engines. When a power is given in both units, the second value is placed in parentheses. You can also meet the safety (or health and safety) markings, it is Brake Horse Power - engine power, not taking into account the power losses resulting from the transmission of the drive, obtained on the dynamometer. There are also whp (or WHP), Wheel Horse Power - effective power transmitted to the wheels; this value is usually lower than the nominal engine power, because it takes into account the resistance caused by further gears (e.g. gearbox), drive system. Commonly, horsepower is understood as British steam horse (HP), which can lead to differences in the calculation of power (both units are translated as horsepower in English, or alternatively: HP (I) - steam horse, from Imperial and HP (M ) - horse power, from Metric). In the past, there was also an ihp (indicated horse power) unit, meaning the theoretical power of a steam engine resulting from the pressure in the cylinders, not taking into account the resistance to motion of the engine itself and other gears.

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