Isolation Transformers can be used in sealed panels.

Press Release Summary:

Offered in 250+ models, isolation transformers feature full load operating efficiencies of 97%–99%. This enables cool operation as well as use in sealed panels without external cooling, while size and weight allow thinner panel construction. Inputs range from 120–600 V, 50/60 Hz, while available outputs include 120, 208, 240, or 277 V with ratings from 1.0–25.0 kVA. Three transformers can be connected in one bank for 3-phase operations.

Original Press Release:

With Efficiencies to 99+%, Cool Operating Isolation Transformers can be Used in Sealed Panels

Cincinnati, OH – A new family of high efficiency isolation transformers from Foster Transformer feature full load operating efficiencies of 97 to 99%, allowing them to run cooler and to be used in sealed panels without external cooling. In addition, they are up to 25% smaller and lighter than current generation transformers, allowing thinner panel construction. They provide a higher degree of isolation (as measured by leakage current to ground).  This, coupled with improved efficiency, reduced size and weight can yield significantly lower operating costs. With input voltage ranging from 120V through 600V, in 50/60 Hz, there are more than 250 models available, matching all common commercial voltages. Output voltages of 120, 208, 240 or 277V, with ratings from 1.0 to 25.0 kVA. These high-efficiency, isolation transformers are ideal for a wide range of commercial and industrial applications, including....

When compared to transformers meeting NEMA TP-1:2002 Energy Efficiency Standards, the 25 kVA model can reduce annual operating expense by $500.00, the equivalent of switching off a 500W heat lamp. Foster also improved safety and reliability with leakage current to ground reduced by more than half compared to previous generation. Their ability to operate in a sealed environment with no external cooling saves additional energy and costs. Three transformers can be connected in a bank for three-phase operations.

"We designed these transformers to be extremely efficient, more than any of the current standard calls for," says Herm Harrison, Vice President. "With reduced size, decreased audible noise, less heat, and greater efficiency, these high efficiency isolation transformers are ideal for a broad range of industrial and commercial applications."

Foster Transformer has been making electronic transformers, power supplies, and electromagnetic components for over 75 years.  Their corporate headquarters, Engineering Lab and primary manufacturing facility are located in Cincinnati, OH with additional manufacturing capacity available in China. The ability to manufacture their own tooling, fixtures and unique production machinery, allows Foster to provide quick turnaround, start-up.  For more information contact Foster Transformer, 3820 Colerain Avenue, Cincinnati, OH  45223, (800) 963-9799, or

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