One horsepower is equal to 550 of these units per second
... One Horsepower is otherwise defined as 550 ft-lb per second (units of... [DOC] [TLE] Convert pound-foot/minute [lbfft/min] <> horsepower (550 ft*lbf/s) [PAR] pound-foot/minute to horsepower (550 ft*lbf/s) (lbfft/min550 ftlbf/s 
measurement units conversion.