Jefferson Electric Transformers



The HMT (Harmonic Mitigating Transformer) is a three phase transformer with 0° or -30° displacement between the primary and the secondary. The HMT is used to reduce current harmonics on the primary side of a transformer and voltage distortion on the load. A single HMT reduces the flow of triplen harmonics, 3rd, 9th, 15th, 21st, etc into the transformer primary. Used together on the same power line a 0° and -30° HMT will also reduce the 5th and 7th harmonics. These transformers are designed to reduce voltage distortion when powering non-linear loads.


  • For use in environments with non-linear loads such as computers and variable speed drives
  • Where there is high computer, printer and communication equipment usage, and stable operation is necessary
  • Medical facilities including hospitals
  • Data centers
  • Office buildings
  • Schools


  • DOE-2016 efficiency
  • 3 phase, 60 Hz
  • 480V primary
  • Zig-Zag secondary design voltage 208Y/120V
  • 0º and -30º phase shifts
  • 15 – 1,500 kVA range
  • Aluminum windings
  • K-13 standard
  • 150ºC temperature rise
  • 220ºC insulation class
  • NEMA 3R enclosure
  • Heat-cured ASA-61 gray powder coating finish
  • Electrostatic shield
  • Cores of high quality electrical steel
  • UL / cUL Rated

Features, Functions, Benefits

  • Space saving design for easy handling and installation
  • Termination lugs provided for ease of installation through 75 kVA
  • Vibration isolation pads provide quiet operation


Options and Accessories

  • 50 Hz
  • Other voltages available
  • Copper windings
  • K-4 and K-20
  • Dual electrostatic shield
  • 115ºC, 80ºC temperature rise

More Power Quality Solutions

To see information on our Harmonic Suppression System (HSS™), patented technology that eliminates 3rd harmonic currents, see this section.


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