Steam horse

Metric steam horse graphic concept

The horsepower (CV) is a unit of measurement of power that is defined as the power required to lift a weight of 75 kgf (735.5 newtons) at 1 m (3, 3 ft) tall in 1 second.

Origin

When the decimal metric system originated in France was established, a value similar to the English horsepower was sought for the unit of mechanical power, but using decimal units. Thus was born the steam horse, cheval-vapeur in French or cavallo vapore in Italian. In its definition (as seen at the beginning of this article), units of the metric system are used. It is only 1.37% less than the horsepower of the Anglo-Saxon system of units.

This unit is widely used in Europe, although horsepower is preferred in other countries.

Equivalences

The relationship between both units and the respective relationships with the watt, power unit of the International System of Units, are as indicated:

Between CV and W (SI)

The relation between the horsepower (CV) and the watt (W), unit of the International System, is:
1 HP = 735.49875 W ≈ 735 W

Between CV and HP

The relationships that exist between both units are:
1 HP = 0.986 320 070 619 67 HP ≈ 0.986 HP
1 HP = 1,013 869 665 423 850 CV ≈ 1,014 CV

Uses

Since the CV does not belong to the International System of Units, it currently has an uneven and frequently imprecise use, since it is confused with the English HP. Thus, it is still customary to refer to the power of automobile engines, boats, etc. in "horses"; but without clarifying what kind of horsepower, either steam (CV) or power (HP). In countries where the International System is the only legal one, the kW is used as a unit of power, although it is accompanied by its equivalence in some type of "horses", for example: in Spain and Chile, normally CV; in Uruguay and Argentina, normally HP.