Poncelet

French (Ancien Régime)Historical unit (no longer in standard use)

Exactly 980.665 watts: 100 kilogram-force meters per second. A 19th-century French unit named after the engineer Jean-Victor Poncelet.

1 poncelet = 980.665 watts (exactly).

About the poncelet

Engineers in 19th-century France measured machine output in kilogram-force metres per second, and the poncelet gave a round figure to that practice: the power needed to raise a 100 kilogram mass at one metre per second. The name honours Jean-Victor Poncelet, a military engineer and mathematician who taught mechanics at Metz from 1825 and later held a chair at the Sorbonne. He is known for improving the undershot water wheel with curved blades, described in a memoir of 1827.

The unit was meant for large installations such as water wheels and turbines, where horsepower-sized numbers were awkward. At 100 kgf·m/s it equals 980.665 watts using standard gravity, which is about 1.315 imperial horsepower. It is exactly four thirds of the metric horsepower (cheval-vapeur, 75 kgf·m/s), and that smaller unit replaced it in everyday use. Wikipedia cites Cardarelli's encyclopaedia of units for the naming and gives little more history.

Today the poncelet is only a historical curiosity. In the SI it is simply a little under one kilowatt.

Sources: Wikipedia: Poncelet (unit); Wikipedia: Horsepower (metric horsepower); Wikipedia: Jean-Victor Poncelet

Poncelet conversion chart

1 poncelet expressed in every other power unit:

More French (Ancien Régime) units

• ligne (length)
• pouce (length)
• pied du roi (length)
• toise (length)
• lieue (Paris league) (length)
• arpent (North American) (area)
• degree Réaumur (temperature)
• degree Delisle (temperature)
• pièze (pressure)
• sthène (force)

All French (Ancien Régime) units

Browse all power units.