Ferroresonant Transformers

MSI Ferroresonant Transformer

Ferroresonant Transformers

Ferroresonant Transformers are also known as Constant-Voltage Transformers (CVT). A CVT regulates its secondary voltage typically within a few percent even when the primary voltage changes as much as 15-20 percent. Accompanying these transformers is a bank of capacitors. These capacitors are used to tune the output voltage of the CVT and are essential to its proper operation.


  • Power rating up to 10 KVA
  • Input range +/- 20% nominal voltage
  • Output regulation +/- 2% nominal voltage
  • Frequency: 60 Hz operation
  • Single phase design
  • Self-cooled construction
  • Supplied with capacitors
  • Aluminum or copper windings



  • UL Recognized insulation system (Primary must be 600V or less). MSI UL Insulation systems are available in 130°, 180° and 220°C ratings
  • CE marking with declaration of conformity ROHS and Low Voltage Directive
  • 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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