GTI specializes in Dry Type Custom Transformers, Reactors & Chokes to meet the demanding requirements of OEM’s.

GTI Facility
  • 55,000sq ft modern, clean facility located in Grand Haven, Michigan
  • Continuous Improvement focused highly skilled workforce
  • Reinvestment in new equipment, technology and expanding capabilities
  • Integrated ERP business system, EPICOR in use company wide
  • Certified CSA Test Facility to CSA 22.2 #66 based on ISO/IEC 17025:2005
  • GTI utilizes LEAN Concepts throughout our production areas with integrated Work Cells, Line Stocking, Cross-Training and 5S.
  • The latest in Computerized Winding Equipment is utilized
  • Voltech Computerized Testers in use extensively
Product Development
  • Dedicated and experienced Electrical Engineering Staff
  • Designs are optimized for performance and cost
  • Comprehensive “State of the Art” design analysis tools in use
    • Optimized Programming Service (OPS) Electro-Magnetic Design
    • Autodesk Inventor Product Design Suite (3D)
    • Mathcad
  • First Article Inspection reports and electrical test data provided with samples
  • Years of experience working with Safety Agencies UL, CSA, TUV, CE, ETL


  • GTI’s “Hunt and Tell” Quality Procedures focus on “Building In” quality rather than “Inspecting In”
  • GTI’s test equipment is fully calibrated and traceable to NIST
  • GTI maintains compliance to ISO9001 Quality Standards since original certification in ‘93
  • Exceptional track record maintaining low percentage of customer returns and in-plant rejects

GTI Custom Products

Single Phase Transformers up to 500KVA
  • UL/cUL 5085 & 1561 Listed & Recognized from 25VA up to 50KVA
  • Isolation, Auto, Encapsulated, K-Rated, High Efficiency, Low Inrush, High Reactance.
  • 50/60 – 400HZ
Three Phase Transformers up to 750KVA
  • UL/cUL 5085 & 1561 Listed & Recognized from 2KVA up to 500KVA Isolation
  • UL/cUL 1561 Listed from 10KVA to 30KVA Autotransformer
  • Isolation, Auto, Drive Isolation, Elevator Duty, Multipulse
    (12, 18, 24), Encapsulated, K-Rated, High Efficiency, High Reactance, Harmonic Mitigating, Zig-Zag, Scott-T
  • 50/60 – 400HZ
AC Reactors and Inductors
  • Single and Three Phase up to 1000KVAR
  • Line and Load Inductors, PWM/High Frequency – Filter Inductors, DV/DT, Air Cores, 5-Leg, Low Profile, Trap, LCL, Low to High Impedance Range, Tightly Balanced and Matching Inductor Sets, Low Audible Noise
  • 50/60 – 20KHZ
DC Chokes and Inductors
  • DC Links, Boost Inductors, Charging Inductors, Filter Inductors, Chokes
  • 120 – 20khz, up to 2500ADC
Construction Options and Value Added Services
  • 5 KV Max Voltage, 30KV BIL
  • UL1446 Insulation System Recognition; 105C thru 220C, up to 15KV
  • Aluminum or Copper windings available
  • NEMA 1, 3R, 4, 4X & IP Equivalents, Standard or Custom
  • Harsh Environment Conformal Epoxy Coatings & Encapsulated Units
  • Filter Assemblies CSA B44.1 Certified to 450Adc, 5mH, RLC
  • RTD’s, Temp Switches, Tap Switches, Arrestors, TVSS, Metering, Fusing, Circuit Breakers, Fan Cooling, Shielding, Grounding
  • Full compliment of “In House” Fabricating, Machining and Assembly
  • Terminal Blocks, Lugs, Wire Harnesses, Specialty Connectors & Leads
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