Mechanical horsepower hp
About the Mechanical horsepower
James Watt defined horsepower to market his steam engines against draught horses, settling on 33,000 foot-pounds per minute, or 550 per second. This is about 745.7 watts. Metric horsepower, the German PS, is a different unit of about 735.5 W, and electrical horsepower is exactly 746 W.
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