Energy efficient motors used for Mpumalanga chrome conveyor system

Automation manufacturer SEW-Eurodrive South Africa (SEW SA) supplied multiple units of its DRN motors to a Mpumalanga chrome producer in August. The energy efficient motors form part of a trial project for a materials handling solution, says SEW SA Mbombela branch manager Jonathan Mckey.

He explains that the motors will propel the mine’s main incline conveyors, which carry mined ore to the surface for handling and stockpiling. The main conveyor is fed by smaller lateral conveyors and two gearboxes are run simultaneously to convey the extreme weights to the surface at an incline.

Mckey notes that the DRN motors are IE3-compliant; therefore, they comply with International Electrotechnical Commission (IEC) standard IEC 60034-30, which specifies energy efficiency classes for single-speed, three-phase, cage-induction motors with two, four or six poles.

He states that IE3-compliant motors typically use innovative materials to ensure that a rated motor is more efficiently designed, allowing for a reduction in energy consumption which, in turn, results in monthly cost savings while ensuring a comparatively quick return on investment.

“The total solution supplied to the chrome producer comprised a 250 kW, 1 475 rpm IE3 B3 IEC SEW motor, high-speed couplings, invertible X-series X3KR210 gearboxes, rigid flange couplings all fitted and laser aligned onto swing-base configurations.”

Mckey says the complete drive solutions were selected and assembled at SEW SA’s Mbombela manufacturing facility, in Mpumalanga. “The units were ordered at the beginning of July and were supplied within the required five to six weeks.”

Contacted by the mine’s engineering team who had heard about SEW SA’s work at other mines, Mckey emphasises that the company’s past success, professionalism and reputation for reliability, combined with its “unrivalled” stockholding, ultimately led to its securing the contract.

Mckey points out that SEW SA’s stock availability was crucial in this case, as the client had strict deadlines. “Depending on the success of the trial, the client may ask us to deliver more of these drives, as well as other units.”

He says the only challenge during this project was trusting third-party suppliers to meet their commitments to SEW SA. “We have to nurture their delivery commitment and manage our time efficiently to ensure there are no compromises on our client’s expectations. Luckily, SEW-Eurodrive aligns itself with dependable, global corporate entities that share its ideals and value its requests.”

Mckey explains that SEW SA’s motors and gearbox components are manufactured and fully imported, and then assembled by various SEW SA plants nationally. All SEW IG gearbox components are imported and stocked at the Mbombela facility and assembled in accordance with clients’ specific needs. “All remaining final drive components are fabricated and supplied by approved global suppliers that have branches in South Africa.”

Canadian Project
SEW SA projects head Rudi Swanepoel notes that SEW SA was approached last year to supply a 24 t ZDN hoist drive to a Canadian gold mine for a hoisting application to convey mineworkers and goods, which “meant that strict health and safety requirements and safety factors had to be accommodated”.

Subsequently, SEW SA secured a major order for the second stage of the project – an ML series unit for a goods-only application, which was assembled at SEW Eurodrive’s manufacturing facility, in China.

The input power of this second hoist drive is 1 000 kW, with a nominal torque of 293 000 kNm. It will be installed on a goods-only hoist lift, in a deeper underground section of the mine and be used for ore transportation.

The unit also has a specially fabricated steel welded housing that has been fitted with internal piping. Swanepoel adds that it uses a motorised pump as part of its pressure lubrication system and has been fitted with an oil cooler and oil level glass.

In terms of the scope of SEW SA’s involvement in the project, the company aided its Chinese contemporaries in the design of the unit and presented the solution to a South Africa-based client, which is supplying the Canadian operation. “It was up to the SEW SA projects department to ensure that the client was satisfied with the proposal and design, and that there was nothing that could jeopardise the project or the working relationship”.

He adds that the ML series unit has been delivered to the client’s freight forwarder in Johannesburg. “The client will be responsible for delivering and commissioning the unit on site early next year.”

Swanepoel notes that one of the reasons why SEW SA has been able to flourish is that its mining clients have “peace of mind that they have superior, technically advanced, German-quality products, supported by expert technical advice relating to gears and power transmission”.