ft·lbf/min

foot pound-force per minute

Powerexact by definition

The foot pound-force per minute is exactly 1/60 of a foot pound-force per second, about 0.0225970 watts. It is the form in which James Watt originally stated the horsepower: 33,000 ft·lbf per minute, from a horse walking a mill circle.

1 ft·lbf/min 0.022596966 W
Where the unit came from

Watt measured mill horses, rounded the result upward by his own account, and then had a commercial interest in the number being large, since he sold engines rated against it. The unit has outlived both the horses and the patents.