The apparatus consists of a wall mounted pulley with a loaded belt. The pulley is made of aluminium and has two machined grooves to suit a flat, vee belt, and a rope. Each belt fits into its respective groove during testing.
For a given belt tension and angle of lap, a turning moment can be applied by adding weights to the pulley drive hanger. The idea is to determine the torque which just causes the pulley to turn, and so to find the ratio of the belt tensions. This enables the belt tension equation to be verified and the coefficient of friction to be determined.
The angle of lap can be easily varied by placing one end of each belt at different angular positions on the wall bracket. A removable pin and bar are used to enable the various angular positions to be achieved.