POWER Engineers

An important detail in the design and installation of belt and roller conveyors is the drive unit. In addition to correct sizing, the designer must always check to make sure that it does not interfere with other equipment and building structures. The designer and original equipment manufacturer (OEM) need to work closely to ensure it is correctly designed, correctly oriented and on the correct side.

The drive unit normally includes a motor, gearbox, shaft coupling(s), along with mounting bracketry and sometimes sprockets, pulleys, belts and/or chains.

The physical size of the drive unit, especially on small conveyors, can make it cumbersome and difficult to mount in an effective manner.

The quantity of spare parts required for maintenance is quite large. The number and type of spare parts has the potential for frequent maintenance, and that maintenance will always require having the correct tools available for disassembly and reassembly.

An inexperienced maintenance person may have difficulty with disassembly and reassembly of the drive components and the time required to make these repairs can be significant.

Long periods of time in corrosive environments can make disassembly very difficult, while frequent and inexperienced maintenance personnel can damage components and make future disassembly and reassembly more difficult.

In many applications, OEMs are now starting to use pulley motors to significantly reduce many of the shortcomings of the traditional drive unit. A pulley motor combines the motor and gear reduction within the cylindrical cavity of a pulley. Shaft couplings, mounting brackets, sprockets, pulleys, belts and/or chains are no longer needed.

The pulley motor can provide the same variable-frequency drive (VFD) capabilities of a traditional drive. When properly designed into a conveyor, it will improve or eliminate many of the drive's shortcomings:

  • Interference problems and getting it on the correct side becomes much less of a problem since only a small electrical connection box extends out one end of the pulley motor.
  • Many times, the elimination of a protruding drive unit will provide the designer with more and better options when laying out a conveying system.
  • Problems related to mounting a large, cumbersome drive on a small conveyor is eliminated.
  • Few hand tools are required (in some cases none are required) to remove a failed unit and replace it with a new one.
  • Corrosion problems are mostly eliminated.
  • Frequent removal and replacement should not cause significant or accumulative damage to mounting hardware.
  • A fairly inexperienced maintenance person can usually remove and replace this drive unit without difficulty.
  • The time required to remove and replace a failed unit can be significantly reduced.
  • Stocking of as many as a dozen individual spare parts is reduced to just one and if this drive concept is common throughout a large factory, even more efficiencies can be achieved.

The list above relates to both belt and roller conveyors. Since pulley motors are now available down to 1.9 in. in diameter, they can be extensively used in standard roller conveyors and can provide the following additional advantages in those conveyors:

  • Eliminates cumbersome V-belt drives on corners
  • Simplifies separating a trunk conveyor into accumulation zones
  • Allows for separating conveyor curves into accumulation zones
  • Enables trunk conveyors to use sensors to run only when product is present, reducing electrical costs
  • Permits wiring for a series of zones to be routed to a common box
  • Allows a series of DC pulley motors to be run from a common drive.

This short article is just a basic introduction to some of the advantages and possibilities that can be achieved with pulley motors on belt and roller conveyors. Innovative machine designers will find many additional applications for this unique drive unit.

This story is sponsored by POWER Engineers, which has one of the most comprehensive teams of engineers and specialists serving the baking and snack industry. As an extension of its clients' engineering teams, the company provides program management, integrated solutions and full facility design for the baking and snack industry. Learn more at www.powereng.com/food.