The Interroll drum motor was first produced in 1953 specifically for use on conveyor belt applications. The aim was to produce an extremely compact, totally enclosed and highly efficient conveyor drive that would be unaffected by dust, water, oil, grease or other harmful substances - which would be quick and simple to install and would require virtually no maintenance.

Today the modern drum motor is considered to be one of the most reliable and effective belt conveyor drives available throughout the world. The Drum motor is in simplistic terms a highly efficient geared motor drive, which is totally enclosed, in a steel cylindrical shell. The shell, which is normally crowned to ensure central belt tracking, is fitted with bearing housings incorporating precision bearings; oil seals and rotates on a shaft. The motor stator is fixed to the shaft and the motor winding cable passes through one end of the shaft, eliminating the need for slip rings and brushes.

The squirrel cage motor manufactured in laminated steel is machined concentric to high tolerances and designed to give 200% starting torque. The rotor pinion is coupled directly to the gearbox. The gearbox transmits the drive directly to the shell bearing housing through a geared rim and provides a high efficiency from motor to drum face with very little frictional losses. The drum motor is oil filled, which acts as both a lubricant and a coolant whereby the heat is dissipated through the shell and conveyor belt.