Tag Archives: Trafo Power Solutions


The priority area of mining today is certainly health and safety, and mines are wanting to achieve this without compromising on meeting their production targets; dry-type transformers are increasingly seen as one constructive way of doing this.

David Claassen, managing director of Trafo Power Solutions, says this is because of their F1 safety rating combined with their low maintenance needs and versatility across mining applications. Their fire safety characteristics include being self-extinguishing and flame retardant, and not emitting harmful gasses.

“Dry-type transformers contain no oil as a coolant, rather using air for cooling,” says Claassen. “This means a much lower safety and environmental risk, so that these units can be readily and safely employed in opencast and underground mines – even in hazardous and space-constrained areas.”

Trafo Power Solutions’ design capability ensures that its transformers can run optimally in even harsh conditions of high dust and moisture levels, while remaining sufficiently cool to reliably carry 100% load. The necessary levels of ingress protection are applied to ensure no dust or moisture enters the unit. This includes working with challenging commodities like coal and graphite.

“To accommodate the space and transport limitations of underground mines, we custom engineer transformers to fit into lift cages in vertical shafts or into decline shafts,” he says. “Our fit-for-purpose designs also ensure that the transformers can be installed with limited footprints in confined spaces.”

Cooling options where the transformer’s footprint is reduced include air-to-air heat exchangers, while for more extreme conditions the company can design and manufacture water-cooled transformers. For opencast mining operations, there is often a requirement for transformers to be moved regularly on skid-mounted platforms.

“This means ensuring a high structural integrity through rigid construction, so that the units can withstand vibration as they are frequently moved over rough terrain,” he says. “Under these conditions, mines can also rest easy that there is no risk of oil leaks from our units.”

He explains that Trafo Power Solutions conduct in-depth analyses of mine applications and conditions to inform its designs. Strategic partner TMC Transformers – a leading transformer manufacturer based in Italy – uses the latest thermo-dynamic software to simulate cooling across the transformers’ hotspots. Cooling options include natural ventilation and forced ventilation, with availability of air-to-air heat exchangers and auto heat exchangers.

“Mines can gain immediate safety benefits from dry-type transformers, while improving their operational uptime,” says Claassen. “With no oil to regularly check and change, our transformers are almost maintenance-free – cutting down on service costs and the related impacts of transformer downtime.”

Partnering with TMC Transformers, Trafo Power Solutions has access to a broad range of high quality cast resin transformers from 50kVA to 25MVA, at system voltages up to 52kV with Class F or Class H insulation systems.


As South Africa’s many thousands of oil-cooled mini substations reach the end of their operating lives, there is scope to replace them with a safer and more economical option, according to Trafo Power Solutions managing director David Claassen.

“These mini substations are located all along our urban streets, in shopping centres and around industrial areas – in close proximity to growing numbers of people,” says Claassen. “As municipalities struggle to maintain these properly, they pose an increasing safety risk and become more expensive to service and repair as they get older.”

He points out that oil-cooled transformers require regular testing and maintenance, including monitoring and replacement of oil at regular intervals to ensure effective cooling of the unit. Without this maintenance, the risk of failure or even explosion is raised.

“Dry-type transformers do not contain oil, being cooled by air moving over the components,” he says. “This is one of the factors behind the significantly lower maintenance required by dry-type transformers, which of course translates into substantial cost savings over time.”

The absence of oil makes dry-type transformers considerably safer, he explains, as indicated by these units’ F1 fire rating. This means that they are resistant to flammability, are flame retardant and generate no harmful emissions.

Having no oil as a coolant also makes dry-type transformers less risky to the environment. The risk of oil spilling from an oil-cooled transformer – which can lead to the contamination of land and water – requires the construction of a bund wall. The dry-type option needs little of this kind of additional infrastructure, and so is more cost-effective to install.

“Trafo Power Solutions has worked extensively with developers of high-traffic infrastructure like shopping centres, ensuring the highest level of safety in mini substations located in high-density areas,” he says. “We are well positioned to supply public utilities with the same benefits.”

He notes that municipalities’ financial resources to service and maintain substations are often severely stretched, so it makes sense for them to seek more economical alternatives. Dry-type transformers are almost maintenance-free, he explains, taking a considerable load off the owners’ maintenance duties.

“We custom-design our solutions for dry-type miniature substations to meet customers’ exacting requirements,” says Claassen. “This includes any variation of medium voltage (MV) and low voltage (LV) needs and specific switchgear as well as customised control and protection options.”

Trafo Power Solutions supplies miniature substations from 200kVA to 2500kVA – ranging from 3,3kV to 33kV on the MV side, and from 400V to 1000V on the LV side. These substations are rated up to IP65 ingress protection.


An important expansion to South Africa’s automotive industry is benefiting from the installation of 10 dry-type transformers and two mini-substations supplied by Trafo Power Solutions. 

The units, for a motor plant near Pretoria, range from 315 kVA to 4 MVA and were custom designed and manufactured to the exacting requirements of the electrical consultants on the project, according to David Claassen, managing director of Trafo Power Solutions.

“Working closely with our customer to finalise the design specifications, as well as with our manufacturing partner TMC Transformers in Italy, we were able to meet the tight turnaround times,” says Claassen. 

He highlights that each of the transformers were required to meet particular design challenges. With the six 3150 kVA units and the 4 MVA unit, for instance, fault levels had to be kept to a certain predetermined maximum. The design parameters for the two 1600 kVA units had to ensure they could withstand a relatively high harmonic content.

“One of our strengths is being able to collaborate positively with both consultants and contractors in high pressure contracts like this one,” he says. “This allowed us to achieve the required designs within the strict schedules, so the end result would be fit-for-purpose and delivered on time.”

Trafo Power Solutions’ flexible and proactive approach allowed them to deliver fully on the project despite occasional disruptions related to the Covid-19 pandemic. 

Claassen notes that the company was able to engage with the customer face-to-face and through virtual platforms, as conditions required. The company also took responsibility for logistical elements of the contract.

“Like the rest of the world, South Africa faces various freight challenges since the outbreak of the pandemic, but our innovative strategies ensured that shipping and customs arrangements were closely managed so we could land the equipment as needed,” he says.

The air-cooled format of the dry-type transformers offers the new motor manufacturing facilities an environmental benefit insofar as there is no risk of oil leaks. The units are also low maintenance and have a high safety rating due to minimal explosion risk. 


Dry-type transformer specialist Trafo Power Solutions will supply two custom-engineered mini-substations to a significant motor plant expansion near Pretoria. 

The two units will be located outdoors, serving to power the lighting system and security requirements of the facility, as well as other loads. While most mini-substations are equipped with conventional oil-cooled transformers, these units have dry-type transformers – delivering a number of benefits to the customer. 

David Claassen, managing director of Trafo Power Solutions, says these include security and environmental factors.

“Used by both the private and public sector, mini-substations must often be located in unprotected areas, making them vulnerable to vandalism and theft,” Claassen says. “The oil-cooled transformers are often targeted for the copper in their windings, as well as the oil for the cooling system.”

The dry-type transformer’s windings, by contrast, are cast in resin so the copper or aluminium cannot be readily accessed. There is also no oil to harvest, further reducing the incentive for criminals to destroy the structure. 

“In terms of environmental considerations, the dry-type transformer does not require any additional protective structure like walls or bunds to contain leaking oil or fire,” he says. “These units also require very little maintenance, easing the managerial and technical burden on the owner.”

While these two transformers are manufactured in TMC Transformers’ world-class facility in Italy, the design and manufacture of the balance of the mini-substation is carried out in South Africa. This gives Trafo Power Solutions a high level of control over the quality of the final product, says Claassen.

“This also allows us to fully test the equipment locally before it is delivered, installed and commissioned on site,” he says. “We embrace the opportunity to manufacture locally as much as we can, to support local industries and enhance job creation.”


Trafo Power Solutions has assisted a large diary producer in a recent expansion, supplying five dry-type distribution transformers to its facilities in a coastal region of South Africa.

“With an application in the food and beverage sector, it is important that any equipment in the plant meets the highest standards of cleanliness and safety,” says David Claassen, managing director of Trafo Power Solutions. “This means no risk of oil leaks or harmful gasses is tolerated, so the dry-type transformer option is ideal, with the added advantage of requiring very little maintenance.”

The transformers are 2MVA units, with 11kVA input stepping down to 400V. The warm and humid coastal environment demanded specialised enclosures coated with painting plan type C5 for demanding conditions. 

“Our transformers are supplied into a wide variety of applications, so our design must often specify special materials and coatings to resist corrosion,” says Claassen. “Where units must operate very close to seawater, for instance, we ensure a selected grade of stainless steel in our manufacturing process.”

The project required Trafo Power Solutions to design, manufacture, test, deliver and install the five tonne units, as well as to assist with commissioning on site. He highlights that the company is always involved, directly or indirectly, in their equipment’s installation.

“In some projects, we will take complete responsibility for the delivery, off-loading, rigging and positioning of transformers for installation,” he says. “Where customers have their own rigging team or arrangements, we still make it our business to be there at the time. These are specialised pieces of equipment and it is important to move them correctly to avoid any possible damage.”

The transformers were fitted into three new substations constructed by the customer last year to power the extended dairy facility. Manufacturing of the transformers was undertaken by Trafo Power Solution’s strategic partner TMC Transformers, a global leader in cast resin transformers based in Italy. The completed units were shipped into Durban, and transported timeously to the customer’s site in KwaZulu-Natal province. 

Dry-type transformers are air-cooled rather than oil-cooled, making them safe to use in enclosed and confined spaces, as the risk of fire or explosion is so low. The absence of oil also makes them suitable for applications where high levels of hygiene or environmental protection are required. These features make them quick and cost-effective to install, as no dedicated infrastructure such as bund walls or brick structures are required.


Noting a marked increase in the demand for dry-type transformers for data centres being built in South Africa, Trafo Power Solutions will supply four 1600 kVA units to yet another data centre in Gauteng.

The country is benefiting from a wave of data centre investments in African countries including Kenya and Nigeria, according to a recent Standard Bank report. The trend is driven by advances in connectivity and data consumption, as smartphone use on the continent grows rapidly. Download speeds are rising which, in turn, boosts data consumption. There is also a global shift – driven by factors like data protection regulations – towards hosting data closer to where it is ultimately consumed.

Trafo Power Solutions managing director David Claassen highlights that data centres are energy-intensive, and need high levels of electrical power. In this context, the appropriate transformers with requisite protection devices are vital to support applications as robust as these. 

“Dry-type transformers are ideal for data centres, especially from a safety, reliability and environmental perspective,” says Claassen. “In addition, the load characteristics need to be considered. To suit the high percentage of non-linear or harmonic load, for instance, these transformers have a design K-factor of 13.”

The units were manufactured to the highest level of quality by TMC, a leading Italian transformer OEM, with whom Trafo Power Solutions has partnered to bring dry-type transformers to the African continent. These low-loss transformers conform to the European Directive EU 548-2014, providing considerable savings in energy consumption. An electrostatic shield is an important element of the design, diverting leakage currents to ground. 

“With our experience in dry-type transformer installations around Africa, Trafo Power Solutions are well equipped to assess the application requirement in data centres,” Claassen says. “In conjunction with our manufacturing partner, we can design and deliver a fast-track solution to meet the end-user’s specific needs.”

It is likely that new undersea cables to Africa will continue to raise broadband capacity, driving the trend for more data centres to be established locally.


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.


Designing a dry-type transformer to function at minus 40⁰C temperatures at an altitude comparable to Everest’s base camp is one of the latest achievements of Johannesburg-based Trafo Power Solutions. 

Supplying to a gold mine expansion in Kyrgyzstan, the company has provided a 3,000kVA transformer with a primary 6,3kV and a secondary 400V specification, which will operate at 4,020 metres above sea level.

“The altitude alone presents particular challenges to the design, in terms of cooling,” says David Claassen, managing director of Trafo Power Solutions. “Most large electrical equipment is rated for 1,000 metres or below, so we had to derate this unit to account for the altitude. The higher the location, the less efficient the cooling – and the temperature range on site is between minus 40° C and plus 25⁰C.”

The eight tonne outdoor transformer has a specially designed enclosure to keep out snow, dust and moisture, while also extracting heat. Claassen notes that there is a risk of condensation when the transformer is turned off under these conditions. 

“We therefore built into our design a control system for automatically heating the enclosure when the transformer stops operating for any reason,” he says. “The heaters will then, of course, be turned off again once the transformer resumes operation.”

Under the demanding environmental conditions, the enclosure was coated with a corrosion resistant C5 paint plan. The design also included a neutral earthing resistor with special surge protection elements. He highlights that Trafo Power Solution’s strategic partner TMC Transformers – a leading manufacturer based in Italy – has extensive experience in producing transformers for these severe conditions.

“A dry-type transformer is well-suited to these cold conditions as there is no fluid involved in the cooling process, and it is fairly straightforward to provide the necessary heating and cooling as required,” he says. “There is also very little maintenance required, which is a great advantage in a remote location like this.”

With travel restricted by the Covid-19 pandemic, the customer could remotely witness the factory acceptance test conducted at TMC’s IEC-approved facility in Italy, which allows all routine and special testing to be done in-house. 

“The online factory acceptance test uses communication technology and cameras around the test bay, including cameras focussed on the technician performing the test,” says Claassen. “This allows the customer to check in detail all aspects of the specifications, and to interact freely with the TMC and Trafo Power Solutions team during the witness test.”

At the start of a project, Trafo Power Solutions will provide customers with a published theoretical test report of the tolerances – in terms of aspects such as losses and impedance – expected by the IEC. These are then compared to the actual readings obtained during the factory acceptance test, where he says the results are invariable well within IEC requirements.


Trafo Power Solutions has customised two dry-type transformers for a coal mine in South Africa’s Limpopo province, allowing the units to be fitted into existing enclosures while meeting the customer’s demanding duty requirements.

“While we would normally supply the transformer together with its enclosure, we are also able to design the solution according to the dimensions available on site,” says David Claassen, managing director of Trafo Power Solutions. 

This required one of the transformers – a specialised 3900kVA unit – to be copper-wound to achieve a smaller footprint suitable to the space constraints without compromising the technical performance. With 11kV capacity on the primary windings, this transformer included four separate secondary windings – for 1810V, 1515V, 1360V and 1210V output respectively. 

“Being located outdoors on a coal mine, the transformer had to be well protected from fine dust and moisture, requiring a specially designed IP54 enclosure,” says Claassen. “At the same time, the transformer’s large size meant substantial heat loss, which needed to be extracted from the enclosure. The design therefore included an air-to-air heat exchanger to recycle cool air in a closed loop.”

The second transformer supplied to the mine was a 1600kVA unit for indoor application, stepping down from 11kV to 550V. Working closely with transformer repair experts Koratech Services, who applied certain modifications to the enclosure, Trafo Power Solutions was able to meet the dimensional and electrical requirement of the application – complete with control and protection system.

“Underground mining often presents space constraints which have to be considered in the design of the transformer or the miniature substation,” he says. “With our expertise and our strategic partnership with leading Italy-based manufacturer TMC Transformers, we can readily cater for these conditions.”

He notes that Trafo Power Solutions also supplies dry-type transformers to the marine industry, which requires not only that transformers can be safely employed indoors, but that they often be accommodated in cramped spaces. This experience enhances the company’s technical capability in underground mines. 

Claassen highlights that both transformers were ordered during the tight Level 5 Covid-19 lockdown in South Africa. Despite similar restrictions in Italy, TMC Transformers proceeded with manufacturing, running a 24-hour, three shift operation to ensure the required social distancing. 

“The high level of collaboration with our strategic partner allowed us to design, build and supply the transformers despite the Covid-19 disruption in 2020,” he says. 

Claassen says the dry-type transformer is ideal for both hazardous and non-hazardous areas of coal mines, as the absence of oil as a coolant makes the solution much safer. There is also much less maintenance required on dry-type transformers.  


Demanding safety requirements in the oil and gas sector are being met by custom-designed dry-type transformers from specialist company Trafo Power Solutions.

“We are seeing growing success in the application of dry-type transformer technology in this industry, where all equipment must be safe to use in hazardous areas,” says David Claassen, Trafo Power Solution’s managing director. “Being air-cooled, these transformers are a safe alternative to conventional transformers, which generally use oil as their coolant medium.”

Oil presents risks of explosion, fire and environmental damage while dry-type transformers, by contrast, can be installed indoors, in confined spaces and in proximity to operational areas where people are present. 

“Through our strategic partnership with leading transformer manufacturer TMC Transformers in Italy, we can design, supply and install fit-for-purpose solutions for hazardous areas,” says Claassen. “TMC’s facilities include state-of-the-art technology and capability, and allow us to compete with the best quality and range available globally.”

In one of Trafo Power Solution’s largest projects to date, it is partnering with TMC Transformers to supply the world-class Mozambique liquid natural gas (LNG) project in that country’s northern Cabo Delgado province. Eighteen dry-type transformers are already on site, inside modular substations for the project’s first construction camp of about 9,500 contractors. 

Also being supplied are 20 specialised dry-type transformers for the project’s gas plant, delivering features that only a few players in the global transformer sector could deliver. 

“These 400 kVA to 1600 kVA transformers will be housed in IP56 enclosures, equipping them for high levels of ingress protection,” he says.