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The Beat of a Different Drum Motor

The drum motor has all drive components—electric motor, gear reducer, bearings—housed inside the drum, providing a safer, more sanitary design, and is capable of communicating with central plant control or other plant equipment.

Alexander Kanaris, president of VDG (Van Der Graaf) U.S. and Canada
Alexander Kanaris, president of VDG (Van Der Graaf) U.S. and Canada

VDG (Van Der Graaf) drum motors are manufactured to power belt conveyors for a wide array of industries, including food processing. In 1985, Alexander Kanaris, president of VDG, established a drum motor manufacturing facility in Brampton, Canada. In 2009, an expanded manufacturing facility was opened in Michigan. Today, over 200,000 sq ft of manufacturing space in the U.S. and Canada employs automated robotic production equipment to produce drum motors. All of the components used in VDG drum motors are manufactured in-house, using American materials and labor.

Implementing sanitation processes to battle bacteria has become increasingly challenging in food manufacturing. The VDG sanitary series SSV drum motor features an all-316 stainless-steel construction and IP69K sealing that can withstand washdown pressure up to 3,000 psi. The enclosed drum motor design has no external moving parts compared to conventional exposed conveyor drives, eliminating areas for bacterial harborage and reducing washdown time and water consumption, while increasing sanitation, efficiency, and worker safety. It also eliminates the maintenance required on external components of a conventional conveyor drive, such as the motor, gear reducer, sprockets, and chain. 

Kanaris has become one of North America’s leading experts on drum motor technology and shares his expertise with ProFood World.


PFW: What are the most important benefits and functions of drum motor technology?

Kanaris: Drum motor belt drive design entered the conveyor drive industry in the early 1950s as a unique drive for belt conveyor applications. Drum motor belt drive design is different from a conventional conveyor drive in that the drum motor has all drive components—electric motor, gear reducer, bearings—housed inside the drum. Without exposed drive components and with no other drive parts rotating outside the conveyor frame, it presents a unique belt drive design. The drum motor also maximizes space utilization and worker safety, as components, such as external electric motor, gear reducer, bearings, chain, and chain guards, all traditionally mounted outside the conveyor frame, are not needed. Those components can be hazardous to staff required to work near conventional conveyor drives and render the conveyor line susceptible to bacterial contamination.

Most standard conventional conveyor drives use a 90-degree gear reducer mounted directly on the drive shaft or use sprockets and chain to drive the head conveyor drive drum. Using a 90-degree gear reducer, especially a worm gear reducer, impedes the efficiency of the drive, resulting in mechanical losses.

PFW: How can drum motor technology improve plant floor efficiency and sanitation?

Kanaris: Due to its self-contained design, the VDG drum motor is space-optimized, allowing more floor or overhead space for conveyor systems, and improves safety since there are no external drive components that can pose hazards. In addition, the VDG sanitary series SSV drum motor allows the belt profile to be machined directly onto the 316 stainless-steel drum, eliminating the need for plastic sprockets that can contribute to foreign material contamination and removing areas prone to bacterial harborage. This sprocketless SSV drum motor is a unique and attractive alternative to a conventional drive for food processing applications by eliminating gaps and crevices where food by-products can accumulate, increasing sanitation, and reducing the amount of time and water required for washdown. 

Drum motors are both spatially and mechanically more efficient than conventional conveyor drives as well. Compared to the 90-degree arrangement of most conventional drives, in a drum motor, the electric motor is connected in-line with the gear reducer, resulting in a 20 to 40% increase in mechanical efficiency, depending on the type of gear reducer it is compared with. This leads to lower energy consumption without any sacrifice in torque or performance. The streamlined design of the drum motor also eliminates the need for chains and sprockets, promoting workplace safety and taking up a much smaller footprint than conventional conveyor drives, which require all components that rotate the drive drum to be mounted externally. Lastly, the amount of time required to install a drum motor into the conveyor frame is significantly less than the time required to install an external conveyor drive.

PWF: How are drum motors maintained?

Kanaris: All VDG drum motors are designed for 80,000 hours of continuous operation before scheduled maintenance is required, drastically reducing the amount of maintenance-related downtime a plant has to account for. An oil change is the only required maintenance.

PFW: Please describe drum motor design in detail.

Kanaris: A drum motor is a cylinder with two square shafts on either side and an electrical connection box protruding on one side of the drum motor that houses the electrical connections. The shafts are square and do not rotate. They are fixed and mounted on the conveyor frame, eliminating the need for pillow block bearings. The electric motor that is housed inside the cylinder (drive drum) is an AC squirrel cage design motor. The stator does not rotate, therefore, there is no need for rotating brushes or slip rings delivering power to the stator windings.

The rotor shaft is the input pinion driving either a two- or three-stage gear reducer. The last stage of the gear reducer is driving a gear ring that is bolted directly to the end-flange, and the end-flange is bolted directly to the rotating drive drum. All internal components, motor, gears, and bearings are working in an oil bath. The drum motor is hermetically sealed and filled one-third with oil. The oil inside the drum motor is used as a lubricant and also provides cooling. When the drum motor is running, the oil transfers the heat generated from the electric motor and gear reducer to the rotating drum and dissipates it to the conveyor belt. As the temperature inside the drum motor rises, the internal pressure can rise up to 1 atm [atmosphere] or 14.6 psi. Because of the internal pressure, it is necessary for the drum motor to be hermetically sealed to prevent oil leakage. 

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INTRODUCING! The Latest Trends for Food Products at PACK EXPO Southeast