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
  • Aluminum or copper windings
  • Supplied with capacitors



  • UL Recognized insulation system (Primary voltage must be less than 600V) – 130, 180, and 220°C systems are available
  • 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
  • Enclosure NEMA 1 or NEMA 3R
  • Thermal switches
  • Test Reports with optional Certificate of Compliance