Determining required horsepower
One theoretical horsepower
1 HP(T) = 33,000 ft-lbs1 minute
Required horsepower
HP(T) = Line Pull (lbs) × Line Speed (fpm)33,000
- HP(T)
- theoretical horsepower required
- Line Pull
- pull at the line, lbs
- Line Speed
- line travel speed, feet per minute
Worked example
Lift a 2,000 lbs load 33 ft in one minute (line speed 33 fpm).
HP(T) = 2,000 lbs × 33 fpm33,000 = 66,00033,000
Required: 2.0 HP(T)
Theoretical only. This equation does not account for any of the inefficiencies inherent in motors, gear reductions, bearings or rigging. The motor on a real unit must be larger than HP(T).
Increasing line pull or line speed without changing horsepower
- To increase line pull without adding horsepower, reduce line speed.
- To increase line speed without adding horsepower, reduce line pull.
Related: Line Pull, Line Speed, Work, Energy, Power & Force.