Jefferson Electric Transformers

Manufacturing Transformers Since 1915

Jefferson’s innovative tradition began with the pioneering leadership of our founders, J.C. Daley and John A. Brennan in 1915. Their vision and dedication earned Jefferson a distinguished reputation of providing diverse magnetic solutions to meet everyday needs.

We enjoy a rich tradition of achieving the highest industry standards for quality, durability and reliability in the commercial, OEM and industrial markets. Our customers trust Jefferson products to provide trouble-free, reliable and long-lasting performance.

Jefferson produces power systems that satisfy everyday needs. Our transformers helped bring radio to life and our radar and gunfire control transformers helped our soldiers win World War II. They dried agricultural grain, dimmed theater lights, rang school bells, ran toy electric trains and performed a variety of other, everyday functions. Our quality and innovative tradition endures today with products such as reactor and ripple filter products for ultra-smooth elevator operation and magnetics used in solar inverters and drive systems.

As products and technologies change, we change with them. Through it all, we listen to our customers’ needs and aggressively pursue opportunities to meet changing market demands. That’s how today’s innovative Jefferson® products become tomorrow’s standard products.

1915 – 1920
  • toy and bell ringing transformers
  • sign transformers
  • automotive transformers, regulators, battery switches, ignition coils
  • vibrating coils
  • spark plug and auto lamp testers
1921 – 1930
  • magneto lamp regulators
  • radio transformers
  • oil burner ignition transformers
  • neon sign transformers
  • industrial, commercial, residential and auto fuses; switch and outlet boxes; powerlets
1931 – 1940
  • power circuit transformers
  • airport lighting transformers
  • fluorescent ballasts
  • mercury street lighting transformers (HID)
1941 – 1950
1951 – 1960
  • pulse transformers
  • washing machine solenoids
  • machine tool transformers; magnetic amplifiers; saturable reactors
  • three-phase transformers; weather-proof fluorescent ballasts; high ambient mercury ballasts
  • neon window transformers with built-in flasher
1961 – 1970
  • crop drier transformer
  • 500 KVA transformer; solid state controls for theatre dimmers
  • UL approved Class F & Class H high temperature insulation systems
1971 – 1980
  • low voltage lighting transformers
  • buck-boost transformers
  • medium voltage transformers
1981 – 1990
  • drive isolation transformers
  • non-linear transformers
1991 – 2000
  • harmonic filters
  • AC line/load reactors
  • three-phase lighting transformers
  • stackable filters/transformers
  • universal mounting industrial control transformer
2000 – 2010
  • drive isolation transformers
  • non-linear transformerstanning be transformers
  • TP1 efficiency transformers
  • Canadian High efficiency certification received
  • encapsulated line expanded to 75kVA
  • ventilated line expanded to 1000kVA
  • Seismic approval of transformers
  • totally enclosed non-ventilated units added
  • merger with Pioneer Power Systems
2011 – present
  • drive isolation transformers
  • non-linear transformers
  • Class I Division 2 transformers added
  • ABS certification obtained
  • Medium voltage product line added through 10,000 kVA
  • 18 pulse transformers line developed
  • DOE-2016 efficiency transition
  • development of harmonic mitigating transformers and patented Harmonic Suppression Systems
  • low voltage ventilated line expanded to 2500kVA