Tag Archives: Zest WEG Group


At Vedanta Resources’ Gamsberg mine in the Northern Cape, Zest WEG Group is working closely with lead contractor ELB Engineering Services as a preferred supplier to standardise on its range of transformers and motors across a number of on-site applications.

The Gamsberg project is South Africa’s largest current greenfields mining project, and will exploit one of the world’s largest zinc deposits. It is being developed at a capital cost of US$400 million and is expected to produce 250,000 tonnes a year of zinc metal in concentrate.

“This is a very exciting project for South Africa, especially as we haven’t seen a new mine being developed in the country for many years,” says Dr Stephen Meijers, chief executive at ELB Engineering Services. “Vedanta Resources has shown real intent in terms of investment in South Africa; not only in this project but in others, and we are proud to be building Gamsberg.”

ELB Engineering Services’ first package of work was the provision of water from the Orange River to the process plant, through an upgraded pump station and a pipeline of about 40 kilometres. The second package is the supply of power from the existing Eskom switching yard via overhead lines to the mine, and the third is the process plant itself covering all aspects from run-of-mine tip through to final product, including process dams and balance of plant.

“First product is expected through the plant by the middle of 2018, with the civil works being largely completed by the end of the second quarter of 2017,” says Dr Meijers. “Structural and mechanical construction on the plant is now starting to become the focus of work, and the pace will continue to be intense until middle of 2018.”

Extreme temperatures on site – down to minus 10 degrees Celsius at night in winter and up to between 45 and 50 degrees in summer during the day – have affected the design and the construction methodology, he says. This has meant making optimal use of the cooler hours in summer, even pre-manufacturing as much as possible at night before placing during daylight hours.

Dr Meijers is a strong believer in partnerships, with much of the project technology being applied through exclusive partnerships with preferred suppliers.

“We’ve worked with Zest WEG Group for many years, and appreciate their professionalism, quality of service and reliable scheduling,” he says. “We have therefore placed a number of the contracts for this important and fast track venture through Zest WEG Group companies.”

As a group of specialist electrical companies, Zest WEG Group’s scope of supply covers two main spheres – the water-related package which focuses on the upgrading of the municipal supply station providing water to the Gamsberg site, and the package for the mine’s zinc concentration plant and related processes.

In this process, Zest WEG Group supplied a number of non-standard products – providing the mechanical and design engineering necessary to ensure that the non-standard specifications could be met, including the redundancy requirements to ensure optimal plant uptime.

“The Gamsberg plant is a showcase for WEG motors and includes four different MV motor ranges that were fit-for-purpose in their different applications,” says Kirk Moss, manager – medium voltage business at Zest WEG Group company Shaw Controls. “These included our new W50 line, the HGF line, large slip-ring motors from our M line, and our W22 line of low voltage IE3 motors; meeting the range of requirements demonstrated Zest WEG Group’s versatility in terms of the multiple MV and LV motor offering.”

Various pole mount and distribution transformers, ranging from 500 kVA to 2 500 kVA, being prepared for transportation to the Gamsberg Project site.

Energy efficiency is a key driver in the project design, with high efficiency W22 WEG IE3 motors being specified across the site. To streamline and facilitate the implementation of this focus, Zest WEG Group was tasked by ELB Engineering Services to coordinate with all the original equipment manufacturers that would use motors to drive their equipment. This is to ensure that the principle of energy efficiency is fully applied across all aspects of the project scope.

“Importantly, we are supplying all the LV motors for the plant, ensuring the project will save considerably on its energy cost by complying with the IE3 energy efficiency standard,” says Moss. “These motor are also IP66 rated with Class H insulation, which enhances the IE3 specification by providing higher ingress protection and accommodating a higher temperature rise.”

The WEG Transformers Africa facility where the various transformers for the project were manufactured.

According to Shaw Controls business development manager Tyrone Willemse, the MV Mill package being supplied for the plant comprise two large 6,5 MW WEG motors – MAF 11 kV slip ring units –specified for the ball and semi-autogenous (SAG) mills.

“The jaw crushers will be fitted with proven, robust 11 kV 400 kW motors from WEG’s HGF line,” says Willemse. “We were also requested to supply the distribution transformers on the plant.

Zest WEG Group’s contribution to the upgrading of the water supply facility involved the provision of eight 3,3 kV 550 kW medium voltage (MV) motors as well as its locally designed and manufactured transformers to provide power to the pump stations.

“This included two 2,5 MVA transformers (reducing 11 kV down to 3,3 kV), as well as four 315 KVA (3,3 kV down to 400 V) units,” says Willemse. “Once again, these were not standard transformer designs but were prepared specifically to suit the specifications of the client.”

The package also includes the new WEG W50 motor, which features a compact size and design; through the application of the latest computational analysis techniques, both the scale and the cooling efficiency have been improved – delivering optimised airflow that enhances the unit’s expected lifespan.

“This means that the performance and temperature rise of these motors is not compromised in any way by its smaller dimensions,” says Moss.

Connected to these motors are WEG MVW01 3,3 kV variable speed drives (VSDs), further enhancing energy efficiencies. These are also compact – just 2,315 mm high, 2,600 mm wide and 980 mm deep including the integral phase-shift transformer – together helping reduce the footprint of the substation.

The Variable Speed Drives (VSDs) also boast a low component count – imperative in terms of reliability – of just three power arms that can be changed in two or three minutes, allowing for quick maintenance and low downtime in the case of replacement.

“Helping to meet the short lead-times demanded in this project, Zest WEG Group was able to leverage the global WEG group’s multiple manufacturing facilities around the world, giving us flexibility in terms of where we build and how quickly we can source product,” says Moss.

Willemse adds that an important aspect of the group’s added value has been its five year guarantee covering the hundreds of LV motors on the project.


With access to years of experience in the Heating, Ventilation Air-conditioning and Cooling (HVAC) market, and its range of quality products to service HVAC applications, the Zest WEG Group can tackle any single product installation right through to a customised solution.

Zest WEG Group sales engineer Francois Liebenberg highlights the company’s fit-for-purpose products, WEG variable speed drives (VSDs), WEG low voltage switchgear for control boards and WEG electric motors, which add significant value to HVAC projects.

“Enhancing our product range is our high level of service, where we can dedicate one of our experienced project engineers to work with the customer during the roll-out of a project,” says Liebenberg. “This streamlines the work and expedites implementation, and all queries can be directed to a single point.”

Zest WEG Group can also allocate an after-sales technician on a 24/7 basis to the customer to facilitate any maintenance, repairs and commissioning before and after the project. When it comes to stock availability, the company maintains large volumes of stockholding, particularly of certain key components. Facilitating high levels of stock availability, either at the premises of the contractor, the end-customer or at Zest WEG Group itself, helps to keep the project on track as there is no delay in sourcing the required parts, and maintenance downtime is kept to a minimum.

Key to the product offering for HVAC applications are WEG’s HVAC-dedicated variable speed drives (VSDs): the CFW701 model for applications up to 110 kW and the smaller WEG CFW501 unit suitable for applications up to 22 kW. The WEG VSD product range includes capabilities such as harmonic mitigation, built-in PLC functionality, by-pass, dry run, broken belt and sleep modes as well as a fire mode. This functionality can be interfaced using the BACnet communication protocol, Metasys and Modbus RTU. The VSDs also feature C3-level RFI filters.

“The speed control provided by these VSDs delivers substantial savings in terms of energy consumption, and also offers comprehensive motor protection,” says Liebenberg.

The company also supplies low voltage switchgear for the control panels in HVAC applications, as well as its WEG W22 smoke extraction motor – often used in basement fans installations. These high efficiency motors are IEC certified as well as SABS approved.


With what is claimed to be the largest mobile oil regeneration plant in Africa, WEG Transformers Africa plays a vital role in extending the life of South Africa’s transformer population and preventing unplanned downtime within electricity transmission systems.

“Ageing transformer oil introduces a number of risks into the performance and longevity of oil cooled transformers,” according to Ronaldo Bertoldi, engineering manager at WEG Transformers Africa. “Moisture and impurities reduce the intended insulating effect that oil has within the windings and produces acid, making it more likely for breakdowns to occur, with potentially severe damage to the transformer itself.”

WEG Transformers Africa (WTA) is able to conduct an oil regeneration service on-site for large transformers – those with at least 5 000 of oil in their tanks. This is done by transporting the regeneration plant by road and setting it up at the location required by the customer. Once linked up to the transformer, the unit circulates the oil through a process which involves filtering it through Fuller’s earth to remove impurities.

One of the many mobile oil purification and repair plants operated by WTA.

Careful sampling of the oil is first conducted – in accordance with ISO and SANS sampling procedures – by the company’s field teams, so that oil testing can establish the severity of the contamination. Laboratory tests, also conducted by WTA, are able to pick up the extent of cellulose breakdown from the insulation around the windings, oil decomposition and any moisture ingress.

“The regeneration process removes acids, as well as absorbing moisture and oil decaying products through a hot oil circulation process through Fullers earth and inline oil purification in a closed loop path,” Bertoldi says.

The process of purification only is shorter, and uses inline micro filters to remove water, alcohol, dissolved gasses, oxides and solid impurities. This is also a hot oil circulation process conducted in a closed loop path, and can usually be conducted in less than a day, depending on the condition of the oil.

The number of ‘passes’ that the oil requires through the system is based on the laboratory tests that indicate the level of contamination.

Most of this work is conducted for end-users of transformers in various industrial sectors, with municipalities currently doing less oil purification or regeneration than in the past.


A full range of approved miniature circuit breakers, offering protection against overload and short circuit in electric conductors, is available from Zest WEG Group.

The WEG MDW and WEG MDWH miniature circuit-breaker line comply with the tripping characteristic curves B and C, according to standards IEC 60898 and IEC 60947-2.

These miniature circuit breakers have been developed to be used in low voltage circuits with direct or alternating current from 2 to 125 A and short circuit breaking capacity up to 10 kA. The full range includes all accessories in both 5 kA and 10 kA, making it possible for the Zest WEG Group to supply customers with complete solutions for specific projects.

All the WEG MDW and WEG MDWH miniature circuit breakers can be used in both commercial and domestic applications.

A WEG double pole earth leakage device.


The WEG MPW range of motor protection circuit breakers offer customers reliable operation in the harsh operating environment found on the African continent. All motor protection circuit breakers in the WEG MPW range are manufactured in accordance with IEC 60947 and UL 508 international standards giving absolute assurance in terms of operational parameters and quality.

The devices offer the benefit of being compact and modular, facilitating space saving within the electrical panel itself. This means the panel can be smaller or where necessary more components can be included in the panel. The WEG MPW range of motor protection circuit breakers are robustly constructed for optimal reliability.

The WEG MPW range facilitates the protection of a wide range of electric motors from 0.16 A up to 100 A. Significantly, the range has both thermal magnetic versions facilitating protection against potential short circuit and overload conditions as well as magnetic only versions which provide protection against short circuits.

Use of the thermal magnetic device will reduce the number of components required when manufacturing a motor control centre. This can translate into a significant cost saving. The magnetic-only version allows the use of electronic overload protection devices which can reduce costs further.

The WEG MPW motor protection circuit breaker is available with a full range of accessories including auxiliary contacts, shunt trips, under voltage releases, door mounting handles and free standing enclosures. The devices are certified to Type 2 allowing continuous operation until replaced. This is important in a production critical environment.