Study enhances materials handling performance and reliability

The goal of this 10-year study, which culminated last year, was to gather information on the reliability and service life of the drives and inverters, as well as any malfunctions and their consequences. The data gathered is expected to improve the overall performance of logistics systems, which has previously been subject to trial and error.

EDEKA's 90,000m2 logistics centre houses 20,000 different products and despatches around 400,000 items per day to supermarkets throughout Germany. According to Hans Lowartz, who heads up Witron's onsite team and who is responsible for the systems at this facility, equipment availability is currently running at an impressive 98.8 per cent.

The study provided crucial information on when preventive maintenance had to be carried out or when items of equipment had to be replaced. Witron's onsite maintenance manager, Joachim Mehl recalls: "This was a very intensive joint project with Lenze. We learned a great deal from it and gained considerable insights into how we might improve equipment specification for these warehouse applications."

For example, it was discovered that geared motors with direct mains connection and using high-inertia, cast-iron fans to achieve soft starting were not an efficient system. Cast-iron fans smooth the acceleration ramps due to their increased inertia but this means the drive has to work harder when starting and brakes were wearing out prematurely. Though it added complexity, electronic methods of soft starting proved the better approach.

An opportunity arose to trial Lenze's Smart Motor, an easy-to-programme, compact drive incorporating motor, electronics and gearbox in a single unit that doesn't require external contactors or soft starts. This flexibility means that a single Smart Motor can be used for a variety of conveyor applications. The first 100 units are now in use and the next 100 are to be installed in the near future.

According to Lowartz, the size and complexity of the Hamm facility proved very useful for this long-term field observation project. The data was reliable and regularly used in the planning of large-scale maintenance activities; they are also expected to help the team with future modernisation plans.

Lenze has also profited from the results, as Lenze's Intra-logistics key account manager, Jrg Krampe concludes: "Whenever an incident occurred, we had detailed information on the operating conditions and running times, enabling accurate assessments to be made of equipment reliability and service life. Using this information, Lenze is thus able to customise its products specifically for warehouse operations and subsequently manufacture them in large production volumes."

To learn more about Lenze, please visit www.lenze.com.