The cast-resin transformer is a dry-type transformer in which the windings are completely encapsulated in epoxy resin. This design is particularly safe and therefore ideally suited to locations with elevated fire-protection or environmental requirements. Over the decades, cast-resin technology has continuously evolved – modern units today achieve efficiencies almost on par with comparable oil-cooled models.
What sets a cast-resin transformer apart?
Unlike oil-type units, cast-resin transformers require no insulating liquid whatsoever. The windings are cast in high-grade epoxy resin under vacuum, which simultaneously provides mechanical protection, electrical insulation, and very good heat dissipation. This makes these transformers ideally suited for use in buildings, subways, hospitals, and industrial facilities.
Key Characteristics at a Glance
- Fully low-maintenance – no oil changes required
- Flame-retardant and self-extinguishing (Class F1)
- Low environmental impact, as no leakage is possible
- High short-circuit strength thanks to homogeneous casting technology
- Power range up to 20 MVA and voltages up to 36 kV
- Vacuum casting technology guarantees bubble-free insulation
- Low noise emissions, suitable for inner-city locations
Frequently Asked Questions
Where are cast-resin transformers typically used?
They are used wherever fire and personal safety are top priorities: high-rise buildings, subways, airports, hospitals, data centers, and industrial facilities with potentially explosive atmospheres. They are also very common in wind turbines due to their low maintenance requirements.
How do cast-resin and oil-type transformers differ in terms of maintenance?
While oil-type transformers require regular oil analyses and, where necessary, filtration, cast-resin models are virtually maintenance-free. A visual inspection, cleaning, and thermographic check every few years is generally sufficient.
How does a cast-resin transformer behave in the event of a fire?
The epoxy resin is self-extinguishing and does not release toxic halogen gases. Once the heat source is removed, any incipient combustion extinguishes itself – a significant safety advantage over oil-filled units inside buildings.
What maintenance is recommended for cast-resin transformers?
An annual visual inspection and cleaning is generally sufficient, supplemented by a thermographic examination every two to three years. The windings are checked for discoloration, cracks, or contamination. Elaborate oil analyses are no longer required at all.
Are you looking for a fire-safe and environmentally friendly transformer for your project? Our specialists will advise you on sizing, protection classes, and installation conditions – get in touch with us.