We are manufacturer and exporter of various types of CVT which are Ferro resonant types and gives Constant Output Voltages.
The ferroresonant transformers, which are also known as Constant Voltage Transformers (CVTs) or ferros, are also good surge suppressors, as they provide high isolation and inherent short-circuit protection.
The phenomenon which makes the CVT special is "Ferro Resonance". This is achieved by resonating of the output secondary coil with selected high stability capacitors. This resonant circuit is so dimensioned that the secondary part of the transformer core is separated during each half cycle. In this way the output voltage of the transformer is nearly constant even for large variation in the Input Voltages. By design Purevolt's CVT has sinusoidal waveform. All problems related to variation / fluctuations in Voltages are affectively handled because of this principle and a constant voltage output of +- 1% is given by Purevolt CVT.
The ferroresonant action is a flux limiter rather than a voltage regulator, but with a fixed supply frequency it can maintain an almost constant average output voltage even as the input voltage varies widely.
In our ferro resonant type transformer or cvt the primary and secondary/sides are separated by large air gap and a magnetic shunt. The combined inductance and capacitance are radically reduced because of this and thereby it gives an effective protection against asymmetric voltage transient. There also exists a phase difference between the input and output voltage in Purevolt CVT. the phase shift varies with the magnitude of load and change in line voltage and helps in suppression of noise. The isolation between the primary and secondary strips away the high frequency components of the normal mode noise and the neutral to ground bonding on the secondary side causes a short circuit for the common mode noise.
Short Interruptions & Dips:-
the output of the cvt is taken from the saturated secondary section of the transformer which has an energy reserve close to 5 -10 ms at full load. This feature is responsible for bridging the small interruptions and large dips in line voltage. i.e. for small duration of power breaks (caused because of phase compensations, switching On/Off of heavy electrical equipment, the Purevolt CVT continues to deliver power from its own energy reserve.