Calculating Required Horsepower For a Horizontal Drag Conveyor. May 06, 2013 · Calculating Required Horsepower For a Horizontal Drag Conveyor (EnMasse Conveyor): There are several ways to calculate horsepower for a drag chain conveyor in a grain handling appliion, however, I have found this shortcut for figuring horsepower for a horizontal drag conveyor to be one of the easiest to use.