When a major local e-commerce company had to install additional conveyor belts due to its growth, it found the perfect answer for its requirements in the MOVITRAC® LTP-B standard inverter from SEW-EURODRIVE (Pty) Ltd.

The complete automation package supplied by the drive and automation specialist included mechanical gearboxes and Variable Speed Drives (VSDs) to cope with the increased demand at its client’s main depot. SEW-EURODRIVE (Pty) Ltd. Mechatronics Representative Rudie Venter reveals that 98 MOVITRAC® LTP-B inverters and accessories were supplied.

Most VSDs ship with individual PROFINET communications cards. However, in this instance, a communications gateway was supplied to which a total of eight drives can be connected at the same time, reducing installation cost dramatically. Without the gateway, the installation would have required 98 individual PROFINET cards.

The gateway communicates with a central system such as SCADA. It gives feedback on aspects such as whether the drives are running and their physical location, in addition to feedback from limit switches along the conveyor.

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 encoder. Therefore they are ideal for conveyor applications, hoists, fans, and pumps.

MOVITRAC® LTP-B is available in six sizes, with power ratings from 0.75 kW to 160 kW. It is especially suited for use in dusty and humid environments. As an alternative, inverters for installation in a control cabinet in the power range from 0.75 kW to 15 kW are available with IP20 ingress protection.

The VSDs installed for this project, which is being commissioned at present, are for torque and speed control in a conveyor application. These drives, with their simple set-up, are DIN rail-mounted, meaning no need for drilling and screws during installation, which is quick-and-easy as a result.

A particular advantage of the MOVITRAC® LTP-B series drives is a ramp-up and ramp-down feature to extend the lifespan 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.