MOTORIZED DRIVE ROLLER (MDR)

A motorized drive roller — also called a motorized pulley or drum motor — packages an electric motor and planetary or helical gearbox completely inside the drum shell of a conveyor pulley. The shaft becomes a stationary mounting axle; power is delivered through a watertight cable gland, and torque is reacted by the shell rather than by a coupling. The result is a fully enclosed drive: no exposed v-belts or chains, no external reducer, IP66/IP69K sealing as standard, and a footprint roughly half that of an equivalent external-drive system.

MDRs come in two broad categories. Heavy-duty drum motors for bulk handling cover roughly 0.25 kW to 132 kW, drum diameters 100–800 mm and belt widths up to 2400 mm. Light-duty 24 V DC MDRs serve unit-load logistics, e-commerce sortation and zero-pressure accumulation conveyors at powers of 20–80 W per roller. The light-duty variant is what most distribution centres mean by 'MDR conveyor': dozens of short MDR-driven zones, each managed by a small ZPA controller, enabling silent, energy-efficient sortation.

Advantages include compact installation in confined transfer towers, intrinsic protection in washdown and food environments, reduced maintenance (oil-bath sealed for life on smaller sizes), and excellent energy efficiency at part-load thanks to direct drive. Drawbacks: higher unit cost, longer lead time, and field repair typically means swapping the entire drum rather than rebuilding components in place.