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ReliaGear XFMR Guard III Harmonic Mitigating

ABB LV Transformer - Guard II  and Guard III

Guard III™ Harmonic Mitigating Transformers help eliminate harmonics, improve power quality, and help save energy by reducing the energy (heating) losses. They maintain DOE2016 energy efficiency even when harmonics are present.

Power supplies that convert AC to DC current – for plant floor equipment, computers, copiers, electronic ballasts, and others –  generate harmonics that create an irregular current waveform. These harmonics, in turn, create power quality problems such as overheated transformers, motors and neutral wires; nuisance breaker trips; and electronic equipment malfunction and failure.


  • Helps improve power quality and helps save energy by reducing heating losses
  • Designed to help reduce operating costs
  • Easy access for installation and service


  • Full-width copper electrostatic shielding standard
  • Unique core and coil design using grain-oriented silicon steel
  • Core and coil assemblies mounted on rubber isolation pads
  • Single piece front/back
  • Lifting eyes provided in top clamp
  • Lug kit included with most units up through 150kVA
  • Copper ground bar kit included with most units up through 150kVA
  • Copper ground strap

Technical specifications

  • 15 – 300 kVA
  • 0° Phase shift; +15 Phase Shift; -15 Phase Shift or -30° Phase Shift
  • Copper windings
  • K-factor load profile of 20
  • Crest factor load profile of 5
  • NEMA 1 and/or 2 drip-proof enclosure
  • Weather shield available for field conversion to NEMA 3R
  • NEMA 3R stainless steel (Type 316) up through 150 kVA

Certifications and standards

  • DOE Standards
  • Seismic qualified


  • Schools and colleges
  • Data centers
  • Medical facilities
  • Industrial facilities
  • Casino and gaming operations
  • Large commercial offices