Trafo Power Solutions TMC cast-resin dry-type
Trafo Power Solutions TMC cast-resin dry-type transformers to 25 MVA and 52 kV.
This model is part of SecondWatt’s transformer research catalogue. Specifications and price observations are included where supported by sources. Equipment availability and commercial terms require confirmation.
Trafo Power Solutions dossier: TMC cast-resin dry-types 50 kVA-25 MVA at 52 kV, IP68 and water-cooled options, and a used-unit inspection checklist.
Trafo Power Solutions catalogues this equipment as cast resin dry-type transformers. The business is TRAFO Power Solutions of South Africa, led by managing director David Claassen: a specialist engineering house that designs and supplies dry-type transformers as the exclusive Africa partner of Italy's TMC Transformers S.p.A., a partnership seven years old as of October 2025. Trafo is not a manufacturer; TMC builds and tests the units.
The actual offering runs 50 kVA to 25 MVA in cast resin or VPI construction at up to 52 kV primary or secondary, with enclosures IP21-IP68, IEC 60076-11 compliance, classes E3, C3, and F1, and cooling from AN through closed-circuit AFAF and water-cooled AFAW/WF. TMC's custom capability covers multi-winding designs for 12-, 18-, and 36-pulse drive systems, extreme harmonics, and secondary currents to 30,000 A.
Markets are African mining, manufacturing, renewables, and infrastructure, including documented coal-mine supply. No used Trafo/TMC-branded unit is listed for sale as of August 2026; the class trades new, engineered per project.
Why it matters
Trafo Power Solutions' documented capability runs to 25 MVA at 52 kV in cast resin, which is the specification buyers should be matching against. The line also demonstrates where dry-type engineering is heading: water-cooled AFWF builds, 30,000 A secondaries, and IP68 enclosures extend oil-free transformation into duties US buyers still default to liquid units for.
Who buys it
African mines, industrial plants, and renewable projects specify Trafo/TMC units for fire-critical, IP-rated, and hazardous-area installations; multi-pulse drive duty is the signature use. US relevance is comparative: TMC's 52 kV cast-resin capability matches GEAFOL's ceiling and exceeds most US dry-type lines.
Role in the data center
Reference point for high-capability cast-resin engineering (52 kV, water-cooled, high-current) rather than a US procurement channel today.
Key specifications
| Power range | 50 kVA-25 MVA |
|---|---|
| Voltage ceiling | 52 kV |
| Construction | cast resin or VPI |
| Enclosure range | IP21-IP68 |
| Classes | E3 / C3 / F1 (IEC 60076-11) |
| Cooling options | AN / AF / AFAF / AFAW/WF |
| Multi-pulse designs | 12 / 18 / 36 pulse |
| Secondary current capability | to 30,000 A |
| Partnership | exclusive TMC Africa partner, 7 years (Oct 2025) |
Technical summary
Range: 50 kVA-25 MVA Voltage: up to 52 kV primary or secondary Construction: cast resin or VPI Enclosures: IP21-IP68 Standard: IEC 60076-11; classes E3, C3, F1 Cooling: AN, AF, AN/AF, AFAF (closed circuit), AFAW/WF (water) Drive duty: 12- / 18- / 36-pulse multi-winding designs Extreme spec: secondary currents to 30,000 A Markets: African mining, manufacturing, renewables, infrastructure Model: engineered by Trafo, manufactured and tested by TMC (Italy)
Major variations
Cast resin versus VPI, enclosure class from ventilated indoor to sealed IP68, hazardous-area builds for Zone I/II discussion, and converter-duty multi-winding designs.
Configurations and options
Units run 50 kVA to 25 MVA in cast resin or vacuum-pressure-impregnated construction. Two published documents give different voltage ceilings and both are current: the product page states 52 kV on the primary or secondary, while the October 2025 partnership article states custom units to 25 MVA with 50 kV primary windings. Enclosures run IP21 to IP68, and cooling is AN, AF, AN/AF, closed-circuit AFAF or water-cooled AFAW and WF. Classes are E3, C3 and F1 to IEC 60076-11. The options that separate this line from volume cast-resin suppliers are the custom ones: multi-winding designs for 12-, 18- and 36-pulse drive systems, designs for extreme harmonic content, and secondary currents to 30,000 A. Everything is engineered per project, and TMC Transformers S.p.A. of Italy manufactures the units and runs routine, type and special tests in-house.
Compatibility and dependencies
For converter duty the phase-shifted multi-winding design has to match the rectifier's pulse number, 12, 18 or 36. Secondary current capability to 30,000 A implies busbar rather than cable termination and a busway or connection arrangement designed with the unit. Enclosure rating decides siting: IP21 for a ventilated indoor room, up to IP68 for outdoor or washdown service, with hazardous-area duty in Zone I and Zone II discussed by the supplier. Water-cooled AFAW and WF builds need a water circuit with its own controls and a failure mode the protection scheme has to account for. Dry construction with an F1 fire class removes oil containment. The commercial dependency is channel rather than hardware: TRAFO Power Solutions is an engineering and supply house acting as TMC's exclusive Africa partner, so support and warranty route through that partnership.
Pricing and availability
Comparable secondary-market band: 2595–9495 $ per unit. Trend: up Electrical Trader's price history, published 2026-04-01, puts power transformer prices up 77% between 2019 and 2026 with a 45-95% spread by model, and attributes about half the move to materials: copper up roughly 70% and grain-oriented electrical steel up 80-100% between 2020 and 2025, together 50-55% of production cost. The same series shows the annual rate easing, from 34.58% in 2022 to 8-10% in 2025 with 3-5% forecast for 2026. Terrapin Construction Group put dry-type lead times at 0-2 MVA at 20-32 weeks on 2026-06-10. Lead time, new: Engineered to order via TMC Italy; no published lead times. Lead time, used or refurbished: No used channel exists for this line; units are engineered to order. Warranty, used: 3-year typical from major US rebuilders.
Lifecycle and maintenance
Cast-resin and VPI dry-type transformers typically serve 25-30+ years with minimal maintenance: periodic cleaning, PD testing on critical units, fan service on AF designs, and torque checks. There is no oil system to sample, so temperature and PD are the condition indicators. Rebuild options are limited compared with liquid units; failed coils are usually replaced rather than repaired, which makes pre-purchase PD and visual inspection decisive for used units.
Thermal and emissions profile
Transformers produce no combustion emissions; the regulatory profile is efficiency and fire class. US low-voltage dry-type units fall under DOE 10 CFR 431 efficiency rules (DOE 2016 levels, amended 2024 with 2029 compliance), and EU-market cast-resin units fall under Ecodesign Regulation 548/2014 Tier 2. Dry-type construction removes oil fire and spill risk entirely, which is why cast-resin units carry IEC 60076-11 fire class F1 and serve indoor and environmentally sensitive sites.
Common failure points
- Partial discharge — PD in resin voids degrading insulation toward failure
- Resin cracking — Cracks from thermal cycling or mechanical shock
- Contamination — Dust and conductive debris enabling surface tracking
- Cooling fans — Failed AF fans derating capacity
- Connections — Loose terminations overheating under load
- Overheating under harmonics — Excess temperature on non-linear loads beyond K-rating
Inspection checklist
Partial discharge — PD test per IEC 60270 practice; readings above 10 pC warrant investigation on cast-resin coils Resin condition — inspect all coils per IEC 60076-11 practice for cracks and crazing from thermal cycling; any through-crack fails Insulation resistance — megger HV/LV/ground; polarization index of 2.0 or higher passes Turns ratio — TTR on all tap positions; deviation beyond 0.5% from nameplate fails Winding resistance — three-phase balance within 2% between phases Contamination — inspect for dust and conductive debris between coils; contamination is a leading dry-type failure driver Cooling fans (AF units) — run-test all fans and verify temperature controller setpoints Temperature sensors — verify RTD or thermocouple channels read within 5 C of a reference at ambient Connections — torque-check HV and LV terminations; thermal-scan at first energization and re-check within 12 months Clearances — verify electrical clearances and enclosure IP rating match the installation environment Class verification — confirm fire/environmental/climatic classes (F1, E2/E3, C2/C3) against nameplate Harmonic suitability — verify K-factor rating (K-4/K-13) against the intended non-linear load profile Core and frame — inspect for shipping damage and loose core bolts; verify single core ground Energization test — verify secondary voltage within 5% on all phases and no abnormal sound level Records — factory test certificate, PD test data, and service history; missing PD data reprices the unit
Procurement channels
Trafo Power Solutions (Africa) engineering and supply; TMC Transformers direct elsewhere. No used Trafo/TMC unit is listed as of August 2026; small dry-type class comps trade on Surplus Record (Hammond step-ups at 2,595-9,495 USD new).
Regional notes
TRAFO Power Solutions is a South African engineering and supply house serving African mining, manufacturing, renewables and infrastructure, and the units themselves are built and tested in Italy by TMC Transformers to IEC 60076-11. There is no documented North American sales channel and no UL or CSA listing for this line as of August 2026, so a US buyer would be importing an IEC-built unit and taking on both the listing question and the Section 232 50% tariff on non-US steel and aluminum content in transformer derivatives, effective 2025-08-18. Frequency and voltage class are set at manufacture.