Transformer Technology & Engineering Design

Transformer Technology

Our transformers incorporate advanced technologies to meet the most demanding industrial requirements. Learn about our core technologies and engineering capabilities.

Core Technologies

• Dry Type Transformer Technology
• Cast Resin Transformer Technology
• High Current Transformer Technology
• Custom Transformer Design Technology

Have a technical challenge? Talk to our engineers to discuss your specific requirements.

The Three Design Levers

Every dry type and cast resin transformer is a compromise between three things: how much heat the insulation can survive, how much space the unit is allowed to occupy, and how much it costs to build. Nothing in the design process escapes that triangle, and a specification that asks for all three at once is asking for a unit that does not exist.

• Thermal class — Class F (155 °C) is the working standard for industrial duty. Class H (180 °C) buys a higher thermal margin, either to handle a hotter ambient or to allow overload without shortening life. It costs more because the insulation system is different throughout.
• Cooling method — AN for small units, AF where forced air can raise the rating by roughly 40 to 50 per cent, and oil based OFAF or OFWF where ratings move into the megavolt-ampere range and air alone stops being practical.
• Insulation system — cast resin encapsulates the winding in epoxy, which suits humid, dusty and coastal sites. Vacuum pressure impregnation is lighter and cheaper but offers less protection against moisture ingress.

Why Harmonic Content Changes the Calculation

A transformer feeding a rectifier, an arc furnace or a variable speed drive does not see a sinusoidal current. The harmonic components cause additional eddy current losses in the windings and in structural steel, and those losses are not predicted by a design calculation that assumes a clean sine wave. The result, if the design ignores it, is a unit that runs hotter than the nameplate suggests and ages faster than expected.

Voltage Classes We Design For

Our range covers 0.4 kV, 6 kV, 10 kV, 11 kV, 20 kV, 22 kV, 33 kV and 35 kV. Ratings span 30 kVA to 6,000 kVA for dry type and cast resin construction, and 25 kVA to 20,000 kVA for oil immersed designs.

Where to Start

If you are specifying a transformer and are not sure which technology applies, send the rating, the voltage, the duty cycle and the installation environment. We will tell you which design the requirement actually points to, and where the compromises fall.