Dry-type transformer specialist Trafo Power Solutions has recently been given a ‘hill to climb’ in terms of design and logistics with a request to supply three units to an underground gold mine in South Africa.

The mine required the transformers to operate in the usual demanding conditions of dust, moisture and heat, according to Trafo Power Solutions Managing Director, David Claassen. However, there were a range of other challenges – not least the weight and height restrictions of a deep mine. While two of the transformers are relatively small – 250 kVA and 630 kVA – the third is a substantial 3,150 kVA.

“The transformers are to operate at about 1 km below surface, and will have to be transported through both an incline shaft and vertical shaft,” Claassen says. “Especially with the larger unit, we had to work very closely with our Italian technology partner TMC to reach a design that could be moved within these constraints.”

Trafo Power Solutions also designed the enclosures locally in a manner that would allow them to be transported in manageable components before being re-assembled underground. The enclosure design had to ensure that, while dust and moisture were kept out, there was still enough air circulation to cool the unit. The dry-type transformers will be supplying loads for a refrigeration plant.

“Trafo Power Solutions conducted the complete designs, which were then verified and vetted by TMC,” Claassen says. “This quality control is central to our approach in ensuring fit-for-purpose solutions.”

He emphasised that the design and manufacture of the units was carried out according to schedule and they are on track to be supplied within the customer’s required timeframes.

“On-time supply is an increasingly important aspect of success for mining companies,” he says. “Mines’ capital expenditure is planned according to the expected returns on any project, and supplier delays can undermine these forecasts.”

Trafo Power Solutions also designed the specialised skid bases for the transformers, to facilitate moving the units to their operating destination. These accommodate the considerable weight of the units, particularly the 10-t mass of the large 3,150 kVA unit.

Delivery of the transformers is expected to take place by the end of the year, with Trafo Power Solutions supervising the installation and commissioning process.