Modern Mining July 2017

PRODUCT News

Containerised power solution for West African gold mine Shaw Controls, a Zest WEG Group company, reports the successful completion of its contract to supply a containerised electrical solu- tion to a gold mine in West Africa. Kirk Moss, MediumVoltage Manager at Shaw Controls, says the con- tainerised solution will supply power to drive a mill on this new mine. “Containerised electrical solutions are becoming increasingly popular as these allow for speed of installation and are a particularly cost effec- tive option for mine and plants operating in Africa,”Moss says. The custom engineered sub-station comprises a medium voltage (MV)WEGVariable Speed Drive (VSD) and a dry-type phase shift trans- former driving a 2 000 kW, six-pole, 6,6 kV squirrel cage WEG electric motor. The VSD is housed in the container while the oil-cooled trans- former is housed outside of it to facilitate heat dissipation. Moss says that ShawControls has an established reputation for engi- neering and manufacturing quality bespoke containerised solutions at its Johannesburg facility. The extensive facility of over 12 000 m 2 is manned by a teamof skilled technical personnel and having the whole construction take place in one facility makes it easier for customers to do all quality and functional checks in one place. This solution under- went testing at Shaw Controls prior to being dispatched to site. “What is particularly interesting about the solution provided is that it has been specifically engineered for this particular application and utilises specialised software for frozen charge protection,”Moss says. The software, which interfaces with the VSD, allows the objective detection of a frozen charge condition by making use of torque mea- surements already being monitored by the VSD. “With the addition of an encoder fitted to the electric motor, we are now able to monitor mill angle. And with the torque and angle measurements it is possible to detect if cascading has occurred within the mill,” he explains. Another innovative feature of this solution is the supply of a Human Machine Interface (HMI) in the form of an interactive touch screen which has been configured to allow different levels of access. This project made use of a WEG MVW01 VSD with 6,6 kV output. The input solution makes use of a 36 pulse rectifier and correspond- ing phase shift transformer. Moss explains that this combination was selected as the best option to minimise harmonics. Zest WEG Group Africa, tel (+27 11) 723-6000

Kirk Moss of Shaw Controls in front of the containerised solution that will supply power to drive a mill on a mine in Mali.

July 2017  MODERN MINING  53