Pages Header Banner 2
Pages Header Banner 1
Pages Header Banner 3

Toll Free: 1.800.387.2840

K-Factor Rated Transformer

Product Overview & Application

45 kVA Cutaway2Today's modern electronic, electric components and circuitry such as computers, copiers, printers, fax machines and display terminals utilize switching mode power supplies for their operation. These switching mode power supplies are non-linear in nature and unlike a linear load which uses current from the power source continuously over the sinusoidal cycle, a non-linear load draws current in pulses from the power source thereby creating harmonic distortion. These harmonics currents cause significant power system problems such as:

  • Circuit breakers and fuses blowing far below current ratings
  • Neutrals in transformers and panel boards are much hotter than their ratings
  • Distributions Transformers are overheating even when operating well within their specified nameplate rating

A K-factor rated transformer is designed to handle a degree of harmonic load currents without overheating. The K-rating number of the transformer (1, 4, 9, 13, 20) is in indication of the amount of harmonic current the transformer is capable of handling. The calculation of K-factor for a given load is outlined in IEEE C57.110 but the table below provides a basic summary of the types of loads each K-factor is suitable for.

K-Factor 1: Motors, Incandescent Lighting, Resistance Heating, Motor Generators (without solid state drives) 
K-Factor 4: HID Lighting, Induction Heaters, Welders, UPS with optional input filtering, PLC and solid state controls 
K-Factor 13: Multiple receptacle circuits in health care facilities, UPS without optional input filtering, Production or assemble line equipment, Schools and Classroom facilities 
K-Factor 20: SCR Variable Speed Drives, Circuits with exclusive data processing equipment, Critical care facilities and Hospital operating rooms

Features & Benefits

  • Electrical Isolation between the supply and load minimizes feedback of noise generated by SCR voltage spikes to the supply.
  • Primary and secondary terminals are front accessible for fast and easy connection.
  • Terminations are clearly marked for easy identification.
  • Neoprene isolation pads are installed between the transformer core & coil from the enclosure in order to reduce noise levels.
  • Transformer core is constructed of high quality grain oriented silicon steel and operated well below the materials saturation levels in order to handle the impact of harmonic voltage and current.
  • Suitable for non-sinusoidal load currents with a K factor of 4 (higher K factors are optional).
  • Extra bracing is provided to withstand the mechanical stresses
  • Neutral terminal rated for 200% of line current rating to handle zero sequence harmonics flowing through the neutral.
  • CAN/CSA 802.2-12 Energy Efficient (Part numbers will have /Z suffix)

Product Specification

Capacity  3 to 333 kVA Single Phase and 5 to 900 kVA Three Phase
Voltage Class  600V
Cooling  Self Cooled (ANN / AN)
Frequency  60Hz (50/60Hz Optional)
Conductors  Copper (Cu) or Aluminum (Al) Windings
Insulation System  220°C (150°C rise) (optional 115°C & 80°C rise available)
Impregnation  Polyester Resin Dipped and Baked

 Meets North American Energy Efficiency Standards:

  • Canada - (NRCan 2019) SOR/2018-201, Amd. 14 & ON Reg. 404/12
K-Factor  Suitable for non-sinusoidal current load with a K-factor not to exceed 4 (K9, K13, K20 Optional)
Primary Taps  Typically +/-2 x 2.5% taps (±5% up to 14kVA)
Sound Level  Meets NEMA ST-20
Enclosure Type  Type 1 or 3R Indoor (refer to catalog)
Enclosure Finish  ANSI/ASA 61 Grey
Warranty  12 Months (See Warranty and Limitations)
Quality System  ISO 9001:2015 Quality Management System
  • CSA Certified
  • UL Listed
Reference Standards
  • CSA C22.2 No 47
  • CSA C9
  • IEEE C57.12.01
  • IEEE C57.12.91
  • IEEE C57.110
  • IEEE Std 519
  • NEMA ST-20
Optional Features & Accessories
  • Electrostatic Shield (single, double, triple or multiple/ultra)
  • Custom sizes (specific kVA ratings)
  • Open type (Core & Coils only)
  • Special Paint/Finish
  • NEMA TP-1 Energy Efficiency (USA); Part numbers will have /Z suffix


pdf Distribution Transformer Catalog (English)
pdf Distribution Transformer Catalog (French)
pdf Maintenance, Operating & Installation Manual (English)
pdf Maintenance, Operating & Installation Manual (French)
pdf Product Guide Specification (English)
pdf Three Phase Electrical Schematic Diagrams
pdf Single Phase Electrical Schematic Diagrams
pdf Transformer Efficiency Calculator