Our commitment to quality begins with selecting the finest raw steel. All cores are made with grain-oriented electrical-grade silicon steel to meet performance and permeability standards.

After selection, our toroidal machines wind the steel to meet your custom specifications. Tight tolerances are maintained during core winding to ensure exact roundness, inner and outer diameter, and height.

A custom core annealing process relieves stress, improves accuracy, and minimizes excitation loss. Cores are tempered in a controlled nitrogen atmosphere to prevent oxidation. Fully automated controllers enable constant monitoring of temperature, nitrogen level, and cycle time.

A two-part epoxy edge seal is applied to prevent moisture ingress and ambient humidity penetration in the most demanding applications. All core surfaces are then insulated with a high-density cellulose-based pressboard to prevent core and coil contact.

Electrolytically refined copper magnet wire is wound around the insulated core using automatic winding machines. Secondary windings are distributed around the toroid for minimal leakage reactance on each ratio.

Insulation-piercing terminals and lead wires are applied using a hydraulic crimper for solid connections. We provide a variety of lead wire materials, configurations, and color code schemes to meet your unique requirements.

Transformers are insulated to perform in oil, above oil, SF6 gas, and high temperature environments. The secondary winding is sealed with a double wrapping of non-porous polyester film for dry applications, or woven cotton tapefor oil.

Our molded resin casting system encapsulates the transformers in a durable exterior finish for superior performance in harsh environments.

Before shipment, we test each transformer for excitation loss, polarity, dielectric properties, and turn ratio. Current transformers are also tested for phase angle and ratio correction factor. All testing documentation is maintained for customer reference.