Transformer innovators since 1945

Medium voltage transformers

Two different types are available for application: cast resin (dry type transformers) as well as oil
immersed transformers.


Cast resin transformers
The cast resin transformer (isolation level up to 36kV and maximum power of 25MVA) is common use
in wind mill applications or on board of ships. The transformers fully comply with IEC and CENELEC
HD464 specifications. The transformer is mostly used at:
- underground environments
- mining industry
- airports
- hospitals
- ship and offshore systems
- water management systems
- wind mills


Special isolation
The transformer is isolated during the production process by casting the primary windings in resin.
This should be done very accurately under the most ideal vacuumized conditions. Should the conditions
not match the required parameters then the transformer can be torn apart due to heated air bubbles in
the resin when the transformer is put on full load. Cooling of the transformer comes from natural ventilation
or can also be forced to prevent overheating during (short term) overload. Wesemann has specialized engineers
for this type of transformers and can advise you during the selection and mounting process of this type of


Cost effective
The cast resin transformer is higher in cost when compared with oil immersed transformers although some
characteristics of this transformer can tribute to chosing it as an alternative for oil immersed transformers. The
compact construction of this transformer and the low total costs of ownership in maintenance offers an interesting
view when the two types are compared. It depends on the application of the transformer as well as the present
situation where the transformer will be used.


Environment and safety
Due to the fact that there is no cooling fluid like in the oil immersed transformer there is no possible danger for
the environment and this makes this type of transformer most suitable for "green areas". The use of a cast resin
transformer is safe and easy to operate.


Oil immersed transformers
The most common type of medium voltage transformer is the oil immersed transformer. For most regular power
distribution systems in substations or other distribution solutions this type of transformer is frequently used.

Wesemann can advise you when oil immersed transformers are to be used in your project. Wesemann and its
Spanish partner Imefy are your premier contact when you need this type of transformer.


Oil immersed transformers
Make: Imefy
- Trackside
- Power distribution
- Utility companies
- Customized design
- Maximum power of 100MVA

Wesemann is supplier of cast resin transformers with its Italian partner EDM Zucchini, part of the Legrand group.

Cast resin transformers
Make: EDM
- Traction (on board) and track side
- 12-pulse/24-pulse rectifier transformers
- Offshore and ship application
- Wind mills
- Customized design
- Maximum power of 25MVA

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