Modern Mining February 2022

pre-empt equipment failure,” says Du Plessis. “This is a vital part of ensuring the lowest possible running cost for a productive plant.” With a focus on optimising plant uptime, Zest WEG ensures a high availability of its low voltage motors in the 525 V range – the power range commonly used in process plants around Africa – up to 450 kW. In the VSD range, there is likewise easy access up to 560 kW rated drives. To further enhance the suitability of its motors for the mining environ- ment, some features such as Class H insulation have been added as stan- dard items. “Our W22 motors also have insu- lated end-shields, for instance, to

render them VSD-ready and are standard from our 315 frame upwards,” he says. “This critical feature prevents the VSDs from causing damage to the motor; unlike the alternative of using an insulated bearing, it is also easier to source a normal bearing if customers need to change a bearing on the motor.” This is part of WEG’s commitment to ensure that its equipment is always fit for purpose, and easily upgradeable should the application require a move from direct on-line starting (DOL) to a VSD at a later stage. Efficiencies WEG’s popular W22 motor range comes in different energy efficiencies, from the IE1 standard efficiency rating to IE3 premium efficiency units and lately the IE4 super premium efficiency motor. Typical value- add features include IP66 ingress protection for the IE3 and IE4 models. To fully leverage the ongoing advances in motor technology, he highlights that process plants must be able to upgrade existing equipment by retrofitting new models onto their current plant footprint. This can be difficult if OEMs make radical changes to their design without considering the footprint, as mines have to deal with the added time and cost of altering the base-plates. With this in mind, WEG has ensured that 95% of its IE4 units have frame sizes compatible with the IE3 equivalents. “It has been quite an achievement to fit the higher efficiency motors into the same frame sizes,” he notes. “This is because more iron and copper is usually required in the design to raise the efficiency levels, and this affects the weight and size of the final product. Our R&D team in Brazil has worked hard to overcome this challenge, and has succeeded.” Maintenance Du Plessis emphasises that all moving equipment in

WEG W22 motors destined for the mining sector.

Wall mounted WEG CFW11 Variable Speed Drives with reactor cabinets on a mine site.

Zest WEG’s Johannesburg head office facility maintains a comprehensive stockholding of product.

February 2022  MODERN MINING  27