With the popularisation of PCs & Electronic Equipment, the constant voltage transformers (CVTs) have also become equally popular. The CVT is simply a magnetic transformer of a special construction that has a capacitor connected across the secondary winding of the transformer. In an ordinary transformer, the primary and secondary windings are wound near each other so that whenever there is a change of voltage across the primary there is a corresponding change in the secondary voltage depending upon the ratio of the turns on the two windings. However, in a CVT the primary and secondary windings are wound


separately from each other, as illustrated in figure. To set up field in between the coils, a separate shunt path is provided between the two windings but an airgap is formed in the shunt path. A capacitor is connected across suitable tappings of the secondary winding. The constructional details of a CVT are shown in the figure.

The reason we use a CVT and not a voltage stabilizer for computer applications is that in the voltage stabilizer relays are present and when these relays operate (switch), the output voltage may be interrupted for a short time. Such a


transient may not be desirable for computers which may cause the computer to reboot. Also, the CVT provides a clean spike-free output voltage. The voltage regulation possible in a CVT also is good.

  • Stabilizer, Spike Suppressor, Line Filter, Isolation Transformer ALL IN ONE
  • Built-in Short Circuit & Overload Protection
  • No interruption at output for small duration line interruptions/Brown-outs.
  • Built-in Spike, Surge & RFI Suppression
  • No electrical noise, as no moving parts or semi-conductors are used.
  • 100 times faster than servo stabilizer.
  • Can work at very low voltages on partial load & Instantaneous voltage regulation
Technical Specs :
"PERFECT CVT" are available in a wide Range from 50 VA to 5000 VA with load test conducted at unity power factor for all ratings.
  • Input Voltage 1 phase : 170V-260V. (Other choices on request)
  • Line Frequency : 50 Hz.
  • Output Voltage : 220/230 ± 1% at no load to full load.
  • Efficiency : 90% (approx) under full load conditions.
  • Output Wave Form : Sinosoidal.
  • Wave Form Distortion : 5% (Approx) under full load conditions.
  • Load power Factor : 0.75% lag to 0.9% lead.
  • Ambient Temperature : -5° C to 50° C.
  • Effect of Frequency : 1.6% (approx) change in output voltage for every 1% change in line frequency.