Types and Selection of Drives:
Single Unsnubbed Bare / Lagged pulley Drive
Snubbed Bare / Lagged Pulley Drive
Single Unsnubbed Bare / Lagged Pulley Drive:
This is the simplest drive arrangement consisting of a steel pulley connected to a motor and the belt wrapped round it on an arc of 180°. This can be used for low capacity short center conveyors handling non-abrasive material. The pulley may be lagged to increase the coefficient of friction.
Snubbed Bare / Lagged Pulley Drive:
Here the angle of wrap is increased from 180° to 210° or even up to 230°, by providing a snub pulley to the driving pulley. In majority of medium to large capacity belt conveyors, handling mild abrasive to fairly abrasive materials, 210° snub pulley drive with load pulley lagged with hard rubber is adopted.
Here belt tension estimated to be high; the angle of wrap is increased by adopting tandem drives. Both of tandem pulleys are driven. The tandem drive with arc of contact from 300° to 480° or more can operate with one or two motors. The location of such drive is usually determined by the physical requirements of the plant and structural constraints.
Special drives with snub pulleys and pressure belts used in heavy and long conveyors.