Efacec Power Transformers Inc. has successfully shipped the largest shell transformer made in the U.S. in more than 20 years. The electrical transformer has the unique feature that it can be delivered in four pieces, overcoming significant transportation restrictions.

The 700-MVA 230-kV GSU transformer is the first of its type ever made in the U.S. It was completely designed, manufactured and tested at the firm’s Rincon, GA facility. A large electric utility bought the first unit made in the U.S., which was shipped last month.

“Going through the complex engineering process and successfully building a large transformer like this is highly encouraging,” said Carlos Carvalho, the Director of the Efacec plant. “It validates our concept of basing a power engineering house here in the USA that will have a worldwide presence.”

The huge shell transformer uses “disassociated phase technology," which allows it to be built in four pieces – three units and a fourth piece that fits on top – and assembled at its destination. The technology, perfected at Efacec’s Portugal plant, makes shipping such large transformers feasible.

Standard three-phase transformers this size normally weigh more than 1 million pounds (or 500 tons), which makes it extremely difficult to get them to the electric power plants. With the new technology, each of the four pieces weighs about 360,000 pounds (or 180 tons), which is below domestic transportation restraints. It also means the plant can make even larger shell transformers in the future.

“We’re convinced of the enormous potential offered by the U.S. market,” said Jorge Guerra, Efacec USA’s Chief Operating Officer. “Especially for large units, our disassociated phase technology offers a unique solution to overcome existing transportation problems.”

The Rincon plant, just outside Savannah, is designed to build large power transformers of both core and shell type, up to 1500 MVA and 525 kV. It recently shipped two smaller shell units to domestic utilities. It also received a multi-million dollar order for 20 unit transformers to be used in two nuclear plants.