WEG SOFT STARTER UPGRADES MILL OPERATION AT SA PLANT

When a process plant in South Africa’s Mpumalanga province needed an improved starting method for its rod mill, Zest WEG was able to supply its WEG SSW7000 medium voltage soft starter.

The plant had recently upgraded to a 450kW, 8 pole, 6600V WEG W50 motor, which was started by a direct online starter. 

According to Fritz Hoogenboezem, branch manager at Zest WEG Middelburg, the soft starter was imported into South Africa from WEG’s Brazil factory in time for the plant’s scheduled shutdown, and was installed by local systems integrator Umagezana Engineering. 

“By avoiding the sudden in-rush of current when the motor is switched on, the soft starter reduces both the mechanical stress on equipment and the peak load drawn from the national power grid,” says Hoogenboezem. 

There is a direct financial benefit to be derived by the customer if their peak consumption reduces to a lower peak demand value. This is because exceeding the maximum demand – as can occur when a large motor starts up – leads to costly penalties being applied by the power utility. The in-rush current to start a heavy-duty load can, in those first few milliseconds, be seven to ten times higher than the level at which the motor is specified. 

“By exceeding the maximum demand, the plant could pay much more than necessary for its power consumption, not just for that month but for 12 months afterwards,” he says. 

The installation of the soft starter was a complex task, according to Umagezana Engineering director Ernest Bean. Once they removed the direct online starter, it was clear that the cable lengths would not fit directly onto the new soft starter. 

“This required changes to be made with the motor control centre (MCC) on the high voltage side,” says Bean. “The different cable lengths meant that cables had to be re-terminated to ensure safe and compliant operation; nine cores or phases were terminated.”

Another challenge was that the door to move the equipment in and out was not wide enough. This required specialised rigging to be carefully planned and conducted, as the WEG SSW7000 soft starter weighs almost a tonne. 

Once the new equipment was installed and connected, Zest WEG’s qualified drives and automation technician Reiner Gundlach assisted with the cold and hot commissioning. Extensive tests were run in accordance with WEG’s detailed OEM specifications, laying the technical foundation for the optimal performance and lifespan of the equipment.

“As a sophisticated medium voltage item, there are numerous aspects that need checking and testing,” says Hoogenboezem. “The results are then communicated with WEG as part of our rigorous quality management procedures.”

Bean highlights that, as a technician in the field, he was impressed by the smart use of fibre optics between the control section and the high voltage operational side. In particular, the functionality test in the soft starter’s software is able to test each individual fibre optic cable using a control voltage of 230 volts, before the system is opened to the full 6600 volts used for operations.

“Among the other benefits of the soft starter is its monitoring functionality, which allows the plant management to closely track the interaction between the motor, the soft starter and the plant PLC,” he says. “Management can at any time log into the PLC and use that interface – together with the soft starter – to view important information such as tonnages processed, and the number and duration of stoppages.”

Umagezana Engineering was appointed by Zest WEG as a distributor for the WEG low voltage switchgear range in January 2021. Its whole team has also recently completed the required MV training for high voltage terminations and cable joints, which was done through a specialist firm accredited by the Energy and Water Sector Education Training Authority (EWSETA).

WALKING THE JOURNEY OF AUTOMATION IN SOUTHERN AFRICA

Mine automation not only holds great potential in Southern African, but it is already seen by many mines as an essential element of their future productivity and commercial sustainability. 

According to Simon Andrews, managing director at Sandvik Mining and Rock Technology Southern Africa, his company has long been applying the world’s most advanced technologies on the sub-continent, with local skills underpinning its success.

“Our differentiator is that we can take state-of-the-art technology – the result of our global investment in research and development – and apply it to the needs of our local customers in their own backyards,” says Andrews. 

He disputes the view that the latest technologies are not applicable in Africa due to factors like skills deficits or infrastructure shortages. Rather, Sandvik Mining and Rock Technology has been leveraging local expertise through an ongoing process of upskilling and change management. 

“Automation is a journey that our customers embark upon over a period of time,” he says. “We support this process through our range of intelligent mining equipment, and through resources like our Fleet Data Management (FDM) system.”

The FDM allows mines to analyse operational data from Sandvik machines, such as pressures, run rates, hours worked and buckets loaded. This information can be used by management to improve the effectiveness of equipment, and to advance toward semi-automation and later full automation. 

The regional jurisdiction of Sandvik Mining and Rock Technology Southern Africa comprises South Africa, Botswana, Zimbabwe, Mozambique, Madagascar and Angola. Andrews highlights that automation has been an important focus of recent contracts in Botswana, South Africa and Zimbabwe – with intelligent models of equipment such as load-haul dumpers (LHDs), articulated dump trucks (ADTs), twin-boom drill rigs and roof bolters on the order lists. The automated applications range from platinum to copper and diamonds. 

He emphasises that the key to progress is close partnership between the technology provider and the mine. This, he says, ensures that technology is applied in a relevant and manageable way that suits each customer’s particular needs and capabilities.

“The capital outlay for automation-ready equipment is an important consideration for any mine, but the real ingredient for future success is the long-term commitment to rolling out the automation process,” he says. “This needs the support of the mine’s head office, its management and its operators on the ground.”

It is clear that mines see this route as increasingly necessary, with more interest forthcoming from the market. The ‘wait and see’ approach is waning, says Andrews, in favour of those who want to experience the benefits that technology offers. 

“Before, we had many mines saying they wanted to talk to us when every aspect of the automation process could be clearly demonstrated in practice,” he says. “Now, they are asking us to work with them to overcome the challenges as they arise. There are more customers wanting to take this journey with us.”

It’s all about the relationship between the customer and OEM, to make the automation process work, he concludes. 

SA’S ENGINE COMPONENT REMANUFACTURING ‘A NATIONAL ASSET’

Offering advantages aplenty – from job creation and cost effectiveness to environmental sustainability and foreign exchange conservation – South Africa’s diesel engine component remanufacturing capability is a strategic national asset.

This is the view of Andrew Yorke, operations director at Metric Automotive Engineering, the country’s most comprehensively equipped remanufacturer of large diesel and gas engine components. With over half a century of experience, the company is a benchmark for what can be achieved in local engineering when expertise and innovation are prioritised.

Having kept abreast of leading technology and global trends, Metric Automotive Engineering today boasts one of the leading crankshaft grinding facilities in Africa. Yorke says this equips the firm – which deals with crankshafts from industrial compressors through to locomotive engines – to grind shafts up to 4,7 metres long and weighing up to two tonnes. 

Its workshop includes seven state-of-the-art, three-axis CNC machines. These are the only units in Africa of this type, capable of performing line-boring, surfacing and blue-printing of engine blocks up to six metres in length.

“Our customers’ loyalty is based on our assurance of world-class expertise and equipment, applied to meet strict international quality systems,” Yorke says. “The original equipment manufacturers (OEMs) of these diesel engines expect their components to be remanufactured for long term lowest cost of ownership, and we achieve this by meeting OEM standards.”

He highlights the valuable opportunity that the remanufacturing sector offers for skills development and employment – now required more than ever, in the light of soaring unemployment. The industry could absorb many more skilled employees if there was renewed commitment to policies and practices that supported local procurement.

“The remanufacturing of these components represents an important recycling activity, which helps governments and customers to meet carbon-reduction targets,” Yorke continues. “At the same time, retaining this vital function within the local economy strengthens economic capacity while reducing the country’s need to spend foreign exchange on imports.”

He warns, however, that OEM pricing of aftermarket parts is making remanufacturing less viable, and needs to be addressed. If the skills required for large diesel engine component remanufacture and assembly are lost, engine testing skills would suffer the same fate. 

“If we ended up only importing new large diesel engines instead of remanufacturing components, we would soon need to import the skills to maintain them too,” says Yorke. “South Africa must be strategic about our economic choices – for instance, by supporting automotive engineering that focuses on engine component remanufacture.”

Metric Automotive Engineering – with its modern workshop facilities for testing, grinding, reprofiling, reboring, surfacing and other specialised engineering services – is an inspiring example of what local engineering can achieve. 

AUTOMATIC LUBE SYSTEM FOR WARMAN PUMPS

Pump failure due to lack of regular lubrication can halt production in a process plant, but despite this risk many plants continue to use manual greasing procedures which are often unreliable. 

Lubricating of pumps is a time consuming and labour-intensive process that is often difficult to control and to conduct with the required level of precision, says Marnus Koorts, product manager – pumps at Weir Minerals Africa. 

“Many minerals processing plants around Africa may not have duty schedules that closely monitor and enforce regular lubrication of pumps with the exact volumes of lubricant,” says Koorts. “In our experience, pumps are frequently under-greased or over-greased, and this can severely undermine the lifespan and reliability of pumps.”

The answer, he says, is the Accumin™ range of lubrication systems from Weir Minerals, designed for use with Warman® pumps. The Accumin™ 250 Lubricator, for instance, includes a 250 ml replaceable lubricant cartridge fitted to a reusable drive unit. 

“The lubricator is driven electro-mechanically, dispensing a consistent dosage of lubricant at precise intervals ,regardless of ambient temperature and back pressure,” he says. “It can even be installed up to five metres away from the lubrication point, allowing operators to gain access to the mounting point more easily than to the pump itself.”

He notes that the lubricators are also simple to maintain. The status of some units can be determined by an LCD display, flashing LED alert system and an on-cartridge recording system. The clear cartridge shows how much lubricant remains.

“The accurate lubrication of pumps pays itself back in improved uptime by avoiding the disruption and consequences of unexpected pump failure, as well as in reduced maintenance costs and even energy consumption,” he says. 

As South Africa’s electricity costs climb and mines work towards energy efficiency as part of their efforts to combat climate change, a more effective lubrication regime makes pumps more economical to run. 

“Bearing wear is a ‘silent killer’ for a pump’s efficiency, demanding significantly more power as it progresses,” says Koorts.

The Accumin™ lubricator also adds to smooth plant operation by freeing up operators to focus on more demanding functions, he concludes. 

SHEQ COMPLIANCE EASY WITH APEX SR900 DOOR

The locally manufactured Apex SR 9000 insulated impact traffic door complies with all relevant safety, health, environment and quality (SHEQ) standards. And this, according to Wim Dessing, sales executive at Apex Strip Curtains & Doors, makes it relatively simple for end-users to be SHEQ compliant.

Each Apex SR 9000 door is locally manufactured by the company to meet specific opening requirements. The door combines functionality with longevity in areas where the movement of pedestrians and goods is particularly high.

Manufactured from a 3 mm ABS skin that retains its physical properties down to temperatures of minus 5°C, the door has been used across a wide range of applications. This includes walk-in cold rooms and similar refrigerated applications. The low maintenance skin is impervious to moisture, acids, petroleum products, animal fats, rodents, insects and salt solutions.

The Apex SR 9000 door’s insulation characteristics are enhanced further by the internal design elements. These include the injection of a high density, non CFC urethane foam into the hollow shell of the door.

Standard vision panels constructed from 3 mm clear polycarbonate sheeting are available in a number of custom sizes. However, the Apex SR 9000 is also available without the vision panel which allows greater flexibility of use.

Additional features include scratch resistance and UBC compatibility for enhanced visibility, and it is available in a choice of six colours.

Apex Strip Curtains & Doors has a network of agents throughout South Africa who offer technical and installation support as well as prompt delivery times.

TRAFO DISTRIBUTES WORLD-LEADING TEMPERATURE CONTROL RELAYS

Italy-based temperature control relay specialist TECSYSTEM has appointed Trafo Power Solutions – a leading local supplier of dry-type transformers – as its distributor in sub-Saharan Africa.

TECSYSTEM has, for over 40 years, been developing and manufacturing electronic and electromechanical devices for controlling temperature on equipment such as transformers, motors, generators and variable speed drives.

“We have been using temperature control relays from TECSYSTEM on our dry-type transformers for many years,” said David Claassen, managing director of Trafo Power Solutions. “The quality of this product makes the company one of the global leaders in this specialised field.”

Andrea Lorusso, sales area manager at TECSYSTEM, says the company is pleased to have the expertise and network of Trafo Power Solutions to give the South African market easier access to its products.

“Trafo Power Solutions understands their operating environment well, and also appreciates the value that our technologies can add to the market,” says Fabrizio Giavenni, sales & marketing manager. “As we continuously develop our product range, customers in South Africa can look forward to more exciting innovations.”

The synergy between the two companies is based on the fact that Trafo Power Solutions equips all of its cast-resin transformers with heat sensors that link to a temperature control system. Wherever there is an unusual temperature rise in a transformer, it is vital that the equipment can automatically generate an alert so that the problem can be investigated and solved, emphasises Claassen. 

“Customers purchasing dry-type transformers are often supplied with a temperature control relay as a separate item – almost as an optional extra,” he says. “This is not our approach; rather, we consider the control and protection requirements as an integral part of the overall scope of designing a transformer.”

Trafo Power Solutions designs a dedicated control and protection panel – which includes a TECSYSTEM relay – to suit the customer’s specific transformer. It is then a simple matter of cabling up the main supply, without having to deal with the complexity of linking up the control unit. 

“This is part of our philosophy of providing a full solution to the customer, not just products,” he says. “We are assisted in this by TECSYSTEM’s wide variety of highly reliable control relays, which ranges from hard-wired configurations to protocols such as SCADA and ethernet.”

The company will also be supplying TECSYSTEM’s air-forced (AF) fan cooling systems for cast resin transformers, says Claassen, with control systems designed and installed by Trafo Power Solutions. These fans are installed on the transformer feet, in a set of three fans on each side of the transformer, directly under the windings. 

“They are typically used for additional protection rather than continuous operation,” he notes. “The fans provide efficient and prompt cooling if and when the transformer temperature exceeds a pre-determined value.” 

The company’s regular use of TECSYSTEM products puts Trafo Power Solutions in an ideal position to assist the market in making effective use of these technologies. There are also adequate stocks held in South Africa to allow for easy availability and quick access to the required products. 

“Our facilities are equipped with the required equipment to test products before shipment to customers, as well as to pre-programme the units according to the planned application,” says Claassen. 

The programming is done on a dedicated simulation desk which is able to replicate the conditions in which the relay is required to operate. This simplifies the job for the customer, who then has only to follow a wiring diagram when installing the relay.  

“We can also play a valuable remote trouble-shooting role for customers throughout Africa who need to update parameters in a relay, for instance,” he says. “With our equipment and expertise, we can ‘mimic’ the unit on our side and then assist them over the phone.”

According to Giavenni, the first micro-processor unit was developed  in 1984 specifically to protect the cast resin transformers from temperature overloads. Continuous research and development by TECSYSTEM has seen ongoing product improvements ensuring reliability.

“Quality is an important cornerstone of our production and all our products comply with the latest technical specifications and ratings. Our R&D department conducts both  preliminary and routine testing from the initial engineering phase right through to production,” he says.

GRUNDFOS SAVES ENERGY FOR GROUNDWATER PUMPING

With greater volumes of groundwater being pumped to meet rising global demand, energy efficient pumping technology is increasingly vital for utilities and companies aiming to reduce energy bills and meet carbon reduction targets. 

Groundwater provides drinking water to at least 50% of the global population and accounts for 43% of all irrigation water, according to the United Nation’s Food and Agriculture Organization. 

“There are cities and even countries that depend entirely on groundwater for their water needs,” says Feroz Khan Mohammed Jaffer, Grundfos regional market development manager for groundwater. “This means a lot of energy is consumed extracting groundwater every day.”

Mohammed maintains that any initiative to reduce this power consumption will assist in decreasing the carbon footprint of the groundwater being used. 

As a company that is constantly innovating to makes its pumps more energy efficient, Grundfos has recently taken another step significant step forward with its SPE range of groundwater pumps. The new range was released to the global market recently in an online virtual launch. 

“The efficiency and reliability of the Grundfos SPE range makes it a best-in-class groundwater pumping system,” Mohammed says. “Lower running costs and lower maintenance costs mean even more economical cost of ownership for municipalities, utilities and other users.”

Kim Jensen, Grundfos senior vice president for water utility solutions and marketing, highlights that the company cares about water and the climate. With its understanding of local regulations and international standards, Grundfos has long been a trusted partner in the market. 

“It’s the first time we have introduced permanent magnet (PM) motors to our submersible pumps,” says Jensen. “This allows customers to save on energy consumption and to conduct smarter asset management.”

The inclusion of PM motors in the Grundfos SPE pumps means significant energy savings into the future, according to Jakob Overgaard, Grundfos global chief product manager for water utility and submersibles.

“Our field trials show that customers have experienced energy savings of 20 to 30% and even more,” says Overgaard. “This means a payback time as short as one to two years.”

Grundfos has extensive experience in the use of permanent magnets in its smaller solar pumps, where this technology has been employed for 20 years already, says Mohammed. The company’s SQF solar pumps have been well proven in community water supply, for instance, including remote villages where grid power is not available. This range only goes up to 1,4 kW, however the Grundfos SPE range extends from 7,5 kW to 45 kW.

“There is a significant efficiency gain in the SPE range, with a 90% plus motor efficiency in the PM motor compared to the 80% plus of the standard asynchronous motor,” he says. “Remember that this comparison is between Grundfos asynchronous motors, so the gain would be even more when compared to other asynchronous motors in the market.”

As solar power becomes more popular as a renewable power source in remote areas, the efficiency of the Grundfos SPE range brings further savings in the number of solar panels required and the space necessary for solar facilities, he says.

The Grundfos SPE pumps are available in nine nominal flow rates – SPE 17 to SPE 215 – allowing a maximum flow rate of 300 cubic metres per hour and a maximum head of 670 metres. There are three material variants for different applications – SS304 for drinking water, SS316 for slightly aggressive water; and SS904L for aggressive water. The pumps can withstand liquid temperatures of up to 60⁰C.

“The SPE system includes a variable frequency drive (VFD) for operating the PM motor, adjusting the speed of the motor to control its performance and run it at close to its best efficiency point,” Mohammed says. “This optimises not only the energy consumption but also the reliability.”

VFDs also allow for smooth start-up and slow-down, reducing motor stress and protecting against over-load or under-load, as well as over-voltage or under-voltage. 

DEMANDING CHUTE DESIGN FOR SINTER PLANT

The recent installation of custom-engineered transfer chutes at a sinter plant in Turkey has highlighted the value of Weba Chute Systems’ decades of experience in design engineering and manufacture.

According to Dewald Tintinger, technical manager and designer at South Africa-based Weba Chute Systems, the application had to deal with sinter material with temperatures up to 700⁰ C, while also reducing the level of material degradation which could undermine the furnace performance.

“The plant process uses heat to produce a solid bed of sinter from imported fines, which is then broken down into manageable clumps of minus 150 mm,” says Tintinger. “Our chute solution had to ensure that these clumps did not degrade unduly as they passed through the chute from the sinter breaker and onto a circular cooler.”

He also emphasises that to ensure the cooling conveyor operates energy-efficiently, the chute delivers a homogeneous feed with coarser material at the bottom and the finer material on top. This is because cooling takes place from below. 

The scale and complexity of the chute structure is substantial, with a double-inlet design and a height of some 12 metres. With top inlet dimensions of 5 metre by 4 metre and 5 metre by 2,5 metre respectively, these chutes were narrowed down to control the stream before widening again to discharge a wider spread onto the cooling conveyor. 

As is common in the design and engineering of Weba Chute Systems, a layer of material passing through is captured using dead boxes, creating a protective lining on the chute surface that reduces wear and resists the impact of high temperatures. The plant had previously been successfully equipped with four chutes from Weba Chute Systems.

“The customer’s experience with our earlier chutes was an indication of what our specialised expertise delivered, especially in terms of fit-for-purpose solutions,” Tintinger says. 

Weba Chute Systems uses the latest discrete element modelling (DEM) software to compute and simulate the interaction of individual particles and boundaries, accurately predicting bulk solids behaviour and building this into each specific design. The company can point to more than 5000 successful chute installations globally underpinning its position as an international leader in transfer point solutions. 

CONCOR TO CONSTRUCT IKUSASA OFFICE BLOCK AT OXFORD PARKS

Concor has been awarded the contract to construct the new Ikusasa office block at Oxford Parks in Rosebank. Work started on the building, which will house Anglo Global Shared Services (AGSS), at the beginning of March 2021 and is scheduled for completion in January 2022. 

The four storey building will be constructed on three basement levels of approximately 10 326 m2 and will have four office levels totalling approximately 7 555m2 GLA. It is anticipated that some 814 ton of rebar and some 8 707 m3 of concrete will be used in the construction of Ikusasa. 

Martin Muller, contract manager at Concor, says that the company is excited to continue constructing within the Oxford Parks precinct. “Our involvement with this exciting development goes back to the construction of the first building which today houses BPSA,” he says. 

The Oxford Parks BPSA building received industry recognition at Construction World’s 2019 Best Projects when Concor scooped the winning place in the Building Contractors category, and the project also received a Special Mention in the AfriSam Innovation Award for Sustainable Construction.

Following on this, at Construction World’s 2020 Best Projects, the Oxford Parks precinct featured again with Concor being recognised as the winner in the Building Contractors category; this time for Building 2 – Life Healthcare’s new 10 000 m2 head office, Building 3 – a 4 000 m2 multi-tenanted building housing inter alia Metier Private Equity and G+D Currency Technology and Building 5 – 3 400 moffices for Arup and Sony Music.

Most recently, Concor completed the Radisson RED hotel which is also part of this exciting new precinct in Rosebank, and is due to be opened in June 2022. 

DEPTH OF ENGINEERING CAPACITY UNDERPINS MINING

Engineering remains the backbone of mining, and is a focus that Murray & Roberts Cementation continues to prioritise through its extensive capabilities in engineering services. 

“More than ever, our customers are looking to us for engineering excellence that will underpin their safety, productivity and profitability,” says Hercilus Harmse, engineering services executive at Murray & Roberts Cementation. “This means retaining a formidable base of local expertise, a well-resourced engineering facility and a range of specialised offerings.”

Located at the company’s 57 hectare Bentley Park premises near Carletonville, south-west of Johannesburg, is some 9,690 m2 of covered workshop space – constantly busy with a variety of engineering activities. The engineering personnel numbers almost 70 permanent, qualified technical staff, with more contractors brought in as work requires, says Harmse. The workshops link with the Murray & Roberts Training Academy, situated on the same site, to further develop hands-on artisan and technical skills.

“Key at our Bentley Park facility is our rebuild and refurbishment workshop for trackless mining equipment,” he says. “We can completely refurbish equipment such as load haul dumpers, drill rigs and utility vehicles from a range of original equipment manufacturers (OEMs).”

This work is conducted on equipment in Murray & Roberts Cementation’s own large fleet, as well as on behalf of mining customers. During 2020, over 30 full rebuilds were conducted for customers, complete with on-site commissioning. 

“Our long history in the sector gives us a depth of knowledge and systems that comply with the necessary ISO certifications, as well as the stringent specifications of OEMs,” he says. “We work closely with OEMs to ensure quality assurance and quality control in line with customers’ expectations and codes of practice.”

The capability includes a fabrication facility for light, medium and heavy steel structures. The company’s fabrication and boilermaking expertise is applied in a number of applications, allowing complete new frames for LHDs and drill rigs to be built from scratch.

“This local refurbishment and fabrication capability is part of our wider contribution to the skills base of the South African economy, which we must nurture in pursuit of inclusive economic growth,” says Harmse. “This local content is today a more formalised requirement in the Mining Charter, but we have been working this way for many decades.”

Murray & Roberts Cementation’s specialised rigging team also plays a vital role in heavy rigging and installations, especially with regard to winders and winder ropes. Providing a scarce skill-set to mines in various countries, the team tackles the roping up of new winders, replacements, tensioning, servicing and remedial rope repairs among its tasks. 

“In response to our own needs – as well as those of our mining customers – we are also active in container conversions for specialised purposes,” he says. “We convert these 6 metre or 12 metre containers into change-houses, laundries, offices, pumping stations or storage facilities, to name just a few uses.”

The technical capability at Bentley Park covers the full scope of trades and skills involved in producing these structures – from metal work and racking to electrical wiring and plumbing.

“Our in-house capacity and experience in delivering this range of engineering services ensures customers of a cost-effective solution and rapid response times, while not compromising on quality,” he concludes.