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.


The WEG W22Xd flameproof motor, available from Zest WEG Group, meets worldwide standards for use in hazardous applications including the mining, chemical and oil and gas sectors. The W22Xd motor is certified in line with European ATEX and International IECEx standards.

ATEX/IECEx certified, WEG W22Xd flameproof motors are designed to cope with the rigours and aggressiveness of explosive atmospheres, while delivering the added benefits of high efficiency. Motors available with the IE2 or IE3 energy efficiency rating offer minimised noise, vibration, and low operating temperature for increased reliability and safety.

The WEG W22Xd flameproof electric motor is classified for Group I (mines susceptible to firedamp) and Group II (surface industries), for gases Group IIB and IIC, suitable for use in hazardous area defined as Zone 1 and Zone 2 – Gases and Vapours, and Zone 21 and zone 22 –Combustible or Ignitable Fibres.

The advantage of one motor carrying dual certification for gas and dust facilitates a reduction in inventory costs for users as a common motor frame can be used with different types and sizes of terminal boxes.

Developed in 2002, the initial range of WEG flameproof motors covered the larger power output segment for low, medium and high voltage supplies up to 11 kV. Following the introduction of motors in frame sizes 315 to 500, the range was extended in 2014 to include larger sizes through to a 710 frame.

Complying with the latest editions of IEC/EN 60079 standards, the WEG W22Xd range allows Zest WEG Group to provide a comprehensive range of hazardous area motor products from IEC frame sizes 71 to 710.

Features of the WEG W22Xd 560 to 710 frame design include a stainless steel tube array which provides air ducts allowing both axial and radial flow paths which optimise cooling of the rotor, stator and critical components such as the bearings. The motor is fitted with an aerodynamic fan and cover for efficient air flow with minimum noise.

Designed using finite element analysis (FEA) software, the cooling system on the WEG W22Xd flameproof motor provides outstanding heat dissipation. This reduces thermal stress on the insulating materials facilitating longer life. It also eliminates hot spots by providing a uniform temperature distribution throughout the frame.

The redesigned main terminal box of the WEG W22Xd flameproof motor incorporates fixing bolt housings that provide protection from impact and other environmental damage. This also prevents accumulation of water whilst providing generous space for easy connections.

There are multiple options available for the main power terminal box and accessory terminal boxes for connecting motor protections such as current transformers, surge arrestors or surge capacitors.

The WEG W22Xd flameproof motor is available with two, four, six or eight poles – with higher polarities available on request – in low and high voltage versions and with a range of outputs from 500 kW to 4 500 kW. The frame has a robust welded steel construction and features solid integral feet to minimise vibration, complementing the low noise outputs.

With the WEG W22Xd range, Zest WEG Group has the capability to provide flameproof motor solutions for application in virtually all extreme conditions including those with ambient temperatures from minus 55°C to plus 60°C and altitudes up to 5 000 metre above sea level.

Zest WEG Group’s product line-up includes low and high voltage electric motors, vibrator motors, variable speeds drives, softstarters, power and distribution transformers, MCCs, containerised substations, mini-substations, diesel generator sets, switchgear and co-generation and energy solutions as well as electrical and instrumentation engineering and project management services.


Leveraging the advantages of a containerised solution, Zest WEG Group company Shaw Controls has provided an optimal medium voltage switchgear solution for the supply of power at a copper mining project in the Democratic Republic of Congo.

The WEG MTW05 MV switchgear, the first to be supplied by Shaw Controls into a mining project in Africa, was installed at the Kamoa-Kakula project in the DRC’s Katanga province, located 25 km west of Kolwezi and 270 km west of the provincial capital of Lubumbashi.

“Our engineers provided an innovative design solution to incorporate the switchgear into a standard 12 metre container, which is more cost effective than fabricating an E-house from scratch,” says Kirk Moss, medium voltage manager at Shaw Controls. “The dimensions of a container make it far easier to transport and to install on site, giving the customer a convenient ‘plug and play’ solution.”

The design was able to fit a 31,5 KA withdrawable metal-clad board into a containerised solution, with innovations that allow back access without compromising on the available space.

“The fully withdrawable circuit breakers and voltage transformers (VTs) make the design ideal for a container, while also improving the ease of maintenance of the circuit breakers and VTs,” says Moss.

The WEG switchgear offers a number of features that are particularly advantageous. For instance, the panel has an arc resistant design with internal arc classification (IAC) of BF ALR 31,5 kA for one second. This is a major safety related feature which not only ensures safer working conditions for personnel but reduces the amount of personal protective equipment they require when working on the system.

“Safety is always paramount in the engineering of solutions by Shaw Controls, and this one is no different,” he says. “In the case of an arc explosion, the gases are vented through an internal tunnel running the length of the board. This way, the gases can be ducted out of the sub-station, further enhancing safety. It also means that little clearance is required above the panel, which saves space.”

The panel also boasts a short-time withstand rating of up to 31,5 kA for three seconds, a considerably high fault level for a panel of this size. The range of WEG MTW05 panels is available in voltages of up to 17,5 kV and currents of up to 2,500 Amps.

The full containerised solution was manufactured at Shaw Controls’ 12 000 square metre facility at Robertsham in Johannesburg, which is manned by a team of skilled technical personnel. A full factory acceptance test was conducted at the company’s premises prior to its dispatch to the mine; with its ‘plug and play’ design, the installation was able to be easily conducted by the mine itself.


The modular design of the WEG low voltage electric motor management system offers flexibility by allowing expansion of its functionalities. Engineered as a plug and play solution, the compact WEG SRW01 is ideal for applications where space is limited. It incorporates state of the art technology and network communication capabilities.

Designed for use with power supplies from 24 to 220 V AC/ DC, the WEG SRW01 has a facility, if selected, to monitor voltage up to 690 V AC and measures current from 0.25 A up to 840 A.

The reliability and precision achieved with the WEG SRW01 smart relay makes it suitable for the toughest industrial applications.

Pre-programmed operation modes allow use in several starting and monitoring configurations; this includes a mode which allows the device to be programmed for an individual application allowing optimum flexibility. The unit provides LED indication for input and output activations status, operation mode status, power supply status, and alarm status.

The digital input and output functions of the control unit are automatically configured as operation mode is selected. The system will also automatically recognise which protocol is in use.

The digital inputs can be configured to monitor external digital signals. Using this feature, the output contact from an external relay can be connected to the digital input of the smart relay. Significantly, it is this feature that allows the user to incorporate various protection mechanisms, such as earth leakage and thermal (PTC), in the same relay.

The WEG SRW01 supports a range of communications networks including DeviceNet, Modbus-RTU, Profibus-DP, and Ethernet (2016). The communications modules can be easily exchanged due to the design of the system. The WEG SRW01 has a USB port for relay monitoring, programming and online back-up through a PC when using WLP software.

Rapid system monitoring and relay parameterisation is done via a Human Machine Interface (HMI) keypad, and the device’s internal memory makes it possible to record up to three parameter settings or user programmes. The relay incorporates a thermal memory circuit which will maintain the motor thermal image, even in the event of power loss. This handheld keypad allows engineers to link up to 250 WEG SRW01 smart relays offering great flexibility.


Electrical contractors are often disadvantaged – both operationally and financially – when their planned contribution to a construction or engineering project is disrupted, but are seldom able to claim compensation for their losses. Disruption to contractors is becoming an even more common occurrence as a result of budget cost cutting on projects, resulting in inadequate engineering and lack of planning early on in the project.

According to Russell Drake, general manager operations at Zest WEG Group company EnI Electrical, disruption occurs when a disturbance or hindrance interrupts the normal working methods of the electrical contractor, reducing their productivity on site.

“When a contractor bids for work, their price is based on a scope of works in a clearly defined environment – where the employer’s guidelines and rules are clearly defined,” says Drake. “The contractor expects to carry out the work in terms of a specific set of norms that determine each unit installation rate.”

This rate is set in line with the ‘bill of quantities’ for rateable works, which are industry norms; the price that is estimated assumes that production will be continuous – in other words, it makes no provision for disruption.

“This tender price also assumes that the management and supervision team performs in the manner necessary to complete the project with the operational resources allocated over a period of time,” he says. “This role is carried out according to the ‘direct field labour’ planned for the project.”

In theory, there is recourse to the employer for compensation when disruption leaves the contractor ‘out of pocket’ – if the expense resulting from the contractor’s loss of productivity is caused by disruption events for which the other party is contractually responsible.

“The problem is that many of the factors behind lower-than-anticipated productivity do not justify a legal claim for compensation for disruption,” says Drake. “These include poor supervision or planning, re-work due to defects, or the inadequate coordination of sub-contractors.”

EnI Electrical highlights, for instance, the negative effects of piecemeal access to the work site, where access ‘on the ground’ does not match the access projections promised by the employers. This disrupts the production environment and destroys the validity of the assumptions contained in the original guidelines and rules of the contract – placing the contractor in a difficult position.

“If the access is forecast to be delayed for some time, the contractor may choose to terminate their excess labour – but this is not often done due to the cost, time and effort,” says Naude. “Another option is to remove the surplus labour from the site, and submit a claim for standing time; the danger here is that some progress is lost – and at a higher cost to the contractor and indirectly, the employer.”

He also points out that the labour force could become negative when some have to work and others stand idle. “This negativity further compounds unproductivity.”

“The option often taken by the contractor is to continue applying their resources as best they can, in an attempt to meet the employer’s completion dates,” he says. “However, the process is inefficient and costs more than what the contractor provided for in their tender.”

So, while it is possible for a contractor to demonstrate where disruption of their work has occurred – by applying analytical methods and techniques to quantify the financial loss – they will often delay the disruption claims in an effort to maintain the relationship with the employer. Unfortunately, this can result in even more disputes.

“Electrical contractors who rely on relationships with their customers can become exposed to contractual risks and lose revenue as result of disruptions,” says Drake. “The risks are exacerbated if the client and contractor do not timeously identify and agree on the impact of potential disruption. The longer the delay, the greater the risk to the contractor’s profitability and the client meeting its completion dates.”

EnI Electrical as a contractor is committed to transparency and to manage the ‘inevitable scope changes’ where these are exploited by many contractors to benefit financially. The company is working to transform the culture of the local contracting fraternity, and spends significant time and effort in developing its teams with strong business and ethical leadership.

“We are on a concerted drive to improve industry practice through the way it approaches its contracts – from bidding through to completion of the works,” he says. “Teams will reflect the size of the project, but EnI Electrical teams’ leadership differentiates the company on site; they are not only technically competent, but also understand the business of construction and are effective in multiple areas. This, the company says, is vital to successfully manage and complete projects.”

EnI Electrical’s open and transparent communication with its customers is also applied within the company, with in-house conferences held annually to share on-site experiences and improve contract performance.

“We do not shy away from examining and discussing what has not worked to its benefit, and how it could improve in these areas – even if this means breaking conventional construction mindsets,” he says.

The company’s results tell their own story: EnI Electrical has recorded growth rates of over 400% since 2010, and enjoyed record revenues in 2015 when most of the economy was struggling. As importantly, it based its success on customer satisfaction, as about 60% of its work is generated by repeat business.

Creative cabling rack installation by EnI Electrical at Maseve Platinum