Power Converter

About 745.7 for mechanical horsepower and 735.5 for metric horsepower (PS). The 1.4% gap is why the same engine carries different figures in different markets.

James Watt measured what a dray horse could lift over time, to give buyers a comparison for his steam engines. It was a marketing unit and it outlived the machines it was invented for.

Power is the rate of energy use; energy is power multiplied by time. A kilowatt is a rate, a kilowatt-hour is a quantity — which is why bills are in kilowatt-hours.

Multiply by 0.2931. A 12,000 BTU/h air conditioner is about 3.5 kW, which is the figure marketed as one ton of cooling.

No. PS is metric horsepower at 735.5 W; bhp is brake horsepower, which is the mechanical figure measured at the crankshaft. They are close and they are not the same number.

A fit cyclist sustains a few hundred watts and can peak far above that briefly. Sustained output over hours is well under a horsepower, which puts Watt's unit in perspective.

Peak is what equipment can produce briefly; continuous is what it can sustain. Marketing quotes peak, engineering uses continuous, and the gap can be a factor of two or more.

A body at rest runs at about 100 watts, which is roughly a traditional light bulb. Sustained physical work adds a few hundred more.

The ratio of real power to apparent power in an AC circuit. A poor power factor means current flows without doing useful work, which is why industrial supplies are charged on it.

Because higher mains voltage allows more power through the same current limit. A 230 V kettle can draw 3 kW where a 120 V one is limited to about 1.5 kW, which is why kettles boil faster in Europe.

On a dynamometer, at the crankshaft or at the wheels. Wheel figures are lower by the drivetrain losses, so the two are not comparable without knowing which was quoted.

Output under standard test conditions — 1,000 W/m² at 25 °C. Real output is almost always lower, since those conditions are brighter and cooler than typical.