Coil Products

Coil Products

With more than 50 years of successful field experience, Trench is the recognized world leader in the design and manufacture of air-core, dry-type, power reactors for all utility and industrial applications. The unique custom design approach, along with fully integrated engineering and manufacturing facilities in North America, South America, Europe have enabled Trench to become the technical leader for high-voltage inductors world-wide.

The history of Trench in coils goes back to the 1950s when Spezielektra – today Trench Austria – started to use glass fiber reinforced plastic as part of the insulation of reactors.

In 1962 Tony Trench invented the world’s first dry-type air-core reactor encapsulated in epoxy-impregnated resin. Superior to existing designs because it replaced the uninsulated cables offered by the competition with individually insulated wire that was both stronger and better protected from the environment, Trench’s new product soon became the worldwide standard.

Trench’s highly developed research and development program constantly addresses new technologies and their potential application in reactor products. Trench welcomes challenges for new applications for power reactors.

Trench’s main product line are air-core, dry type coils with benefital design features such as

  • Epoxy impregnated, fiberglass-encapsulated construction
  • Aluminium construction throughout with all current carrying connections welded
  • Highest mechanical and short-circuit strength
  • Essentially zero radial-voltage stress, with uniformly graded axial-voltage distribution between terminals
  • Low noise levels are maintained throughout the life of the reactor
  • Weatherproof construction, with minimum maintenance requirements
  • Design service life in excess of 30 years
  • Designs available in compliance with ANSI/IEEE, IEC and other major standards- Sound mitigation up to 30 dBA

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Successful FAT testing of Trench Austria’s ARCC

Successful FAT testing of Trench Austria’s ARCC (advanced residual current compensator), which is a further evolution of Trench Earth Fault Protection system.


  • Traditional Arc suppression coil with fast motor drive for basic adjustment
  • State-of-the-art multilevel inverter connected to the auxiliary to compensate residual current at the failure location
  • Resulting in lowest possible energy at the failure location to prevent arcing and e.g. wildfire ignition

Trench Austria could demonstrate the functionality of the system by a hardware in the loop test set-up providing full power. Several load cases have been simulated and the test results did confirm the calculations and expectations. A complete assembly together with TA’s proven earth fault detection system has been shipped to the client for a pilot installation and on-site verification of its features.


More than

units in service worldwide

make Trench the recognized world leader for coils

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