Manufacturing & Delivery

World-class manufacturing and testing operations enable HPS to produce the most advanced and reliable dry-type transformers in the market today.

By deploying the latest manufacturing advances and leading-edge test methods, we can build performance and reliability advantages into every transformer.

The multi-national strategy of HPS provides us with the ability to shift products between plants as required to give customers key advantages in delivery schedules, flexible capacity management, disaster proofing and balancing foreign content.

“Quality Control and Continuous Improvement is Part of Everyone’s Job”

HPS employees have a passion for continuous improvement in all phases of the design and manufacturing processes in order to meet the specific requirements for a broad range of customers, for even the most onerous of transformer applications.

Core Construction

HPS cores are manufactured from high grade non-aging, fully processed silicone steel laminations. Cores are precision-cut to close tolerances using modern equipment, to eliminate burrs and optimize energy efficiency. The completed core is sealed in epoxy to reduce the risk of exposure to moisture.

Coil Construction

Coils are available in either aluminum or copper construction. Coils are precision wound with continuous copper or aluminum conductors and are electrically balanced to minimize axial short-circuit forces. The particular design of the ducts inside the coils permits the flow of air, thus providing excellent cooling in addition to providing superior axial mechanical strength.


High-quality temperature and mechanical resistant materials are used as insulation materials to give the transformers a long lifetime for every temperature class requested. Particular solutions can be taken when the installation has difficult ambient conditions (humidity, pollutions, chemical agents, etc.).

Core and Coil Assembly

Coils are held rigidly in place between insulators clamped to the upper and lower core frames under high compression. Winding terminals can be secured firmly to the transformer structure. Particular additional fixing devices are provided when high mechanical performances are required (in case of presence of vibration, of earthquake resistances, etc.).


A critical element of long-term transformer performance is the integrity of the dielectric properties of the insulation materials. In order to meet the designed life expectancy, the impregnation process has to be made with a very accurate and repeatable cycle.

Coils are placed in a sealed tank and one full atmosphere of vacuum is drawn.

The impregnation resin is then introduced into the chamber and the coils or assembly, and is then completely immersed in the impregnation resin.

The coils or assembly are removed from the chamber and oven-cured.

The result is transformer coils that exhibit virtually corona-free performance, a superior resistance to environmental conditions and a new standard of reliability even for the most demanding industrial, utility or commercial applications.

Cast Resin Process

With this process, the windings are encased in a solid epoxy resin.

HPS offers maximum protection of the coils from dust and corrosive atmospheres.

Coils are placed in a mold and the resin is added under vacuum atmosphere.

The coils are then removed from the chamber and oven-cured.

The quality of the processes is checked with the value of partial discharge.

The average values of partial discharge measured on HPS cast resin transformers are significantly lower than the maximum request by the standard due to the overall quality of the materials and process.

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