Tag Archives: Shaw Controls

WEG Automation Africa overcomes logistical challenges at DRC tin mine

Mine operation news, Mining equipment, Mining services, Precious metals, , , , ,

WEG Automation Africa has come to the rescue of a tin mine in the Democratic Republic of Congo, providing a containerised substation and control room solution that circumvented the challenging logistics associated with accessing the operation.

The company, formerly Shaw Controls, put the contract win down to an innovative and fit-for-purpose design.

Tyrone Willemse, Business Development Consultant – Projects and Contracts at WEG Automation Africa, said the substations are each housed in a 6-m-high cube container, with a total of 14 units supplied, comprising MV rooms and LV rooms.

Willemse says: “The unit’s dimensions and robustness had to allow for a long journey, including along a very difficult 200 km road to reach the mine site.”

He added: “Every part of the process plant has its own designated MCC (motor control centre) that provides electrical power and control for areas including the primary crushing circuit, the plant feed, regrind mill, tailings thickener, and the product dewatering and handling circuits.”

In addition to meeting safety compliance regulations, the design includes three-way locking systems, LED lighting, fire detection systems and a safety interlock to the fire system for air conditioners. Backup power supply is provided to all the exit lighting, according to WEG. To ensure easy cable entry, meanwhile, glanding plates were carefully located not to overlap with the container’s support beams.

“Working in close collaboration with the engineering house, careful planning could be done upfront to ensure that nothing was overlooked,” Willemse said.

“In the design, full consideration was given to the placement of elements like platforms, walkways, doors, viewing windows and air conditioning units. We also took responsibility for the logistics of getting everything to site.”

Willemse highlighted that this turnkey solution demonstrated WEG Automation Africa’s containerised substation design and engineering capability, as well as its full local manufacturing capacity, which he said, lifted the company above other MCC manufacturers or assemblers.

The containerised solution comes with a full data pack, quality control documentation and an operation and maintenance manual in accordance with ISO9001.

“With our expertise, capacity and experience of working in Africa, we were able to reduce the risk and turnaround time by tackling the entire contract in-house,” Willemse said. “The extensive testing and cold commissioning enabled by our modus operandi and facilities also gave the mine peace of mind that the unit would function as required when it arrived on site.”

Zest WEG companies supply DRDGOLD with electrics for Far West Gold Recoveries project

Mine operation news, Mining equipment, Mining services, Power supply for mines, Precious metals, , , , , , , , ,

WEG Automation Africa and WEG Transformers Africa, part of the Zest WEG Group, have assisted with the commissioning of a containerised substation and control room solution at DRDGOLD’s new Far West Gold Recoveries project’s Phase 1 tailings site, in South Africa.

The gold tailings recovery project will see 500,000 t/mth of material pumped from the Driefontein 5 dam through a new 2 km pipeline to the Driefontein 2 plant.

Business Development Manager for Projects and Contracts at WEG Automation Africa, Tyrone Willemse, said the development of Phase 1 began in August 2018, with first commissioning beginning just four months later, in December 2018.

In an unusual step for such a project, the electrical portion was supplied ahead to the mechanical aspects to expedite the contract, according to Willemse.

“At the tailings facility, the customer required a medium voltage substation, a low voltage substation and a control room,” Willemse said. “This was accommodated within a double-container structure, which also included a room to house all the free-standing variable speed drives (VSDs) and uninterruptible power supplies (UPSs).”

The container was mounted on a concrete plinth with 2.5 m pillars elevating the structure to allow optimal visibility from the control room, according to the company. Heat losses were factored into the design to ensure the substation remained cool and the installation was fitted with a fire detection system.

Willemse said an important consideration was to reduce the footprint of the substation, with free-standing VSDs allowing this.

“Had the VDS configuration been a conventional design, these units would have been incorporated in panels and we would have needed an additional container,” he said. The VSDs are placed against the container wall and are completely isolated from any exposed conductors.

Motor Control Centres (MMC) were also provided for the modifications to the Driefontein 2 plant. The MCC for the thickener is fed by two 1,600 kVA transformers and the tailings MCC is fed by one 1,600 kVA transformer; both were manufactured at WEG Transformers Africa’s Wadeville facility.

Stuart Brown, Sales Team Leader at WEG Transformers Africa, said: “For this project, the transformers are designed to incorporate the VSD component of the load, and this demonstrates the engineering flexibility that WEG Transformers Africa can offer customers in meeting specific operating parameters. It is not a distribution transformer as such, but rather a VSD-type transformer.”

Cooling capacity had to be increased to accommodate the harmonics, and flux density is also reduced. The WEG transformers are built to SANS 780 specification, which stipulates losses even lower than the global IEC standard, according to the company. This will translate, over time, into energy savings for the customer, and is an important advantage, according to Brown.

Fabrication of all MCCs and the adaptations to the container were undertaken by WEG Automation Africa at its facilities in Robertsham, Johannesburg, and Heidelberg, further adding to the high local content on this project. This local manufacturing capability is a part of Zest WEG Group’s status as a B-BBEE Level 1 contributor.

Particular care was taken with on-site modifications at the plant itself. At the milling and classification MCC extension, WEG Automation Africa was required to connect to DRDGOLD’s existing MCCs. “The use of joggle chambers on either side of the existing board made for best practice and greater safety,” the company said. “On the return water MCC, a raised plinth was added for easier cable access. Top entry cables for the slurry receiving and tailings MCC was facilitated by innovative board design.”

The MCCs incorporate an extensive range of WEG LV products including WEG air circuit breakers to facilitate a 50 kA fault level, WEG moulded case circuit breakers, WEG contactors, WEG fast-acting high rapid fuses, and WEG motor protection relays.

WEG W22 LV electric motors were selected to drive the tailings facility pumps, ensuring lower energy consumption through the design of these units, which have an optimal cooling fin design, the company said. Ingress protection is to IP66 ensuring effective sealing against liquid and dust.

WEG Automation Africa, formerly known as Shaw Controls, recently changed its name to align with parent company, Brazil-based WEG’s global strategy. Its local manufacturing operation has been the recipient of an extensive investment programme by WEG that has seen its facilities upgraded as part of the ongoing commitment to the South African economy and customers in the region.

aluzinc simplifies and speeds up Shaw Controls’ MCC manufacturing process

Equipment maintenance, Mining consumables, Mining equipment, Mining services, , , , ,

The replacement of steel by aluzinc in the manufacture of Shaw Controls motor control centres (MCCs) has brought with it a range of benefits, Shaw’s Senior Manager Operations, Anderson Kohler, says.

“Traditionally, we used only steel for our MCCs, which needs to be powder coated in order to protect it from corrosion,” Kohler said. “This made it necessary to follow quite a long process in completing our products – a process which aluzinc can now simplify and speed up.”

The usual process of preparing MCC panels includes welding, grinding and prewashing before the powder coating painting process can take place. These phases can now be bypassed by using aluzinc; a material that resists corrosion without a protective coating being applied.

Kohler highlighted the extended lifespan of aluzinc, which comprises 55% aluminium, 43.5% zinc and 1.5% silicon – manufacturers of the product guarantee it will last for about 35 years before any major maintenance is required.

He said the powder coating of steel panels complicates the earthing requirement on an MCC, as the paint layer insulates the panel and prevents conductivity. “This means that technicians and installers must take special care to ensure that proper contact is made between the unit and the earth connection,” he said.

For instance, the use of star washers must be strictly enforced among installation staff. Alternatively, certain areas of the MCCs are left unpainted to allow for earth connections. This does raise the concern that it only takes a small oversight and the earthing will not be fully effective, Kohler pointed out. The use of aluzinc eliminates this issue as there is no longer a paint layer between the earth connection and MCC panel, he said.

Shaw Controls said: “There is also the possibility of painted parts being scratched or damaged during transport and installation. When this occurs, it leads to the time consuming task of being returned to the factory for proper powder-coating, further delaying the installation and commissioning process. Indeed, if there is a need to weld again for any reason, then there is a repeat process of grinding and pre-washing before painting again.”

Kohler said the corrosion-resistant properties of aluzinc allowed parts to be kept in stock, ready for quick assembly; something not possible with mild steel due to corrosion.

“By introducing the use of aluzinc in the manufacture of our MCCs, we can reduce the lead time on components by as much as two to three weeks, and this is a time-saving that we can pass on to our customers by delivering more quickly,” he said.

There are also environmental benefits to using aluzinc as a replacement, said Kohler. No welding means a saving on gas and electricity, for instance, while no pre-washing obviates the need for harsh chemicals. In the painting process, there is invariably waste created through surplus paint that must be carefully disposed of in terms of environmental regulations.

Shaw Controls, a Zest WEG company, has over 30 years’ experience as a manufacturer of MCCs, distribution boards, medium voltage switchgear, control desks, PLC and instrumentation enclosures, portable and containerised substations, E-Houses and various other electrical enclosures.