The Ferroresonant Transformer (Type) Voltage Regulator
- Constant voltage transformer
- Constant voltage regulator
- Ferroresonant voltage regulator
- Ferroresonant transformer
The ferroresonant transformer or constant voltage transformer has a very long history having been invented in 1938 by Joseph Sola and continuing to sell tens of thousands of units per year. The ferro of today has had some minor improvements but remains fundamentally unchanged from the original design.
Well known for its longevity, some CVTs are found still in service after more than 40 years. Limited to single phase applications, the ferro is slowly being displaced by small electronic voltage regulators.