Auto Transformers

Auto Transformers

MSI Auto TransformerAuto transformers have one winding which acts as the primary and secondary. As a result, when compared to a traditional transformer of equivalent KVA rating, an auto transformer will be smaller, lighter. For voltage ratios that do not exceed about 3:1, an auto transformer is typically a less expensive option than an isolation transformer. If isolation between input and output is not a requirement for your application, an MSI auto transformer is an excellent choice.


  • Power rating up to 2500 KVA
  • Up to 25 kV class, 125 kV BIL
  • Single, three or two to three phase configurations available
  • Frequency: 50, 60, and 400 Hz standard, inquire about other frequency ratings
  • Self-cooling, forced air cooling, or water-cooled construction
  • Aluminum or copper windings



  • UL Recognized insulation system (Primary voltage must be less than 600V). MSI UL insulation systems are available in 130, 180, and 220°C ratings
  • CE marking with declaration of conformity, ROHS and Low Voltage Directive where applicable
  • Private labeling with customer supplied nameplate artwork. Units that are private labeled cannot carry our UL label
  • NEMA 1 (indoor) or NEMA 3R (outdoor) enclosure with ANSI 61 gray powder coat finish
  • Temperature monitoring thermal switches, thermocouples, or platinum RTD’s
  • Final test reports with optional Certificate of Compliance



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