Drive engineering company SEW-Eurodrive has supplied 98 MOVITRAC LTP-B inverters for conveyor belts installed for a local e-commerce warehouse, in Johannesburg.
SEW-Eurodrive was contracted by materials handling specialist Neptek to supply the inverters for the conveyors that have been installed at the warehouse as part of the expansion project.
For this project, Neptek was responsible for the mechanical optimisation, which included the layout, design and installation of the conveyors.
Subsequently, Neptek also contracted electrical solutions provider Unilec South Africa for the electrical programming, including the installation of the panels and SEW-Eurodrive inverters.
Neptek CEO Richard Nepgen explains that because SEW-Eurodrive inverters were already installed in other parts of the warehouse prior to this project, it seemed an obvious choice to contract SEW-Eurodrive for the additional inverters that were needed for the new conveyor belts.
Unilec software manager Brad Chamen notes that the inverters were easy to install and “ran straight away”.
The standard inverters are matched to meet the requirements outside of the control cabinet. These inverters are developed for open-loop speed control of asynchronous and synchronous motors without an encoder, making it ideal for conveyor applications, hoists, fans and pumps.
Further, the complete automation package, which was installed by Unilec and supplied by SEW-Eurodrive, included mechanical gearboxes and variable-speed drives (VSDs) to handle increased demand of the warehouse’s main depot.
SEW-Eurodrive mechatronics representative Rudie Venter explains that most VSDs are equipped with individual Profinet communication cards.
However, in this instance, a communications gateway was supplied to which a maximum of eight drives can be connected simultaneously. This significantly reduced installation costs. Without the gateway, the installation would have required 98 individual Profinet cards.
Venter explains that the gateway communicates with a central system, such as supervisory control and data acquisition, and provides feedback on whether the drives are running and their physical location, in addition to feedback from limit switches along the conveyor.
The VSDs installed for this project are for torque and speed control in a conveyor application. These drives are Deutsches Institut für Normung, or DIN, rail-mounted, so there is no need for drilling and screws during installation, making it quick and easy to do so as a result.
The MOVITRAC LTP-B inverter is available in 19 sizes, from 0.75 kW to 160 kW. It is especially suited to use in dusty and humid environments. As an alternative, inverters for installation in a control cabinet from 0.75 kW to 15 kW are available with an ingress protection of IP20.
A particular advantage of the MOVITRAC LTP-B series is a ramp-up and -down feature to extend the life span of the gear unit by limiting inrush currents, which can damage the motor windings. The motors used are the latest IE3 premium efficiency versions available.
Nepgen concludes that the client is using the in-bound area in the warehouse while it is still “sorting out some software issues in out-bound, to ensure that the system runs at optimal capacity. . .”