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Infinity Voltage Stabilisers

Specialist, precision high-speed Solid-State Voltage Stabiliser with extremely high output voltage accuracy.

Our Infinity stabilisers have an ultra-fast correction time of <3ms with up to 0.3% voltage output accuracy (True RMS), and now with an extended correction range of up to 30%*, they are perfectly suited for all applications including remote installations with more demanding ambient conditions.

Infinity's unique transductor technology has over 50 years of service in the field and leads the industry in terms of reliability. This is "true fit and forget" technology, is completely maintenance free and comes with a standard 10 year warranty - there is nothing to match it.

Available in single and three phase configurations up to 260kVA/160kVA

*Standard output tolerance of ±15% can be tailored to an asymmetrical output of either ±10%/20% or ±20%/10%

The Infinity range of solid state AC voltage stabilisers and power conditioners are based on our unique low distortion inductive power control concept. Infinity provides the reliability of solid state control without the use of power semiconductors in the supply line, which can be damaged by voltage or current surges, as is the case with solid state tap changers.

Behind the Infinity series lies the vast technical and field applications experience gained since 1952 when Watford Control first manufactured the original range of AC voltage stabilisers.

The twin transductor design was first introduced and patented in 1964. The original patented design was significantly improved in 1971 by the addition of a low distortion transductor assembly. For the first time electronic voltage stabilisers could give high accuracy and reliability in service, with impressively low harmonic distortion achieved without costly filtering.

Principle of Operation

A twin transductor assembly forms a potential divider across two taps of an auto-transformer, one side of which is connected to the incoming mains supply, the other to the load.

A solid state amplifier monitors the output voltage across the load against a highly stable reference voltage. Any error voltage is amplified and directly coupled to the control windings of the transductors, thus altering the voltage across the load and reducing the error to zero.

The transductors are not susceptible to damage from short circuits or voltage surges and the amplifier operates at low voltage and current level. Infinity's unique technology gives you:


  • Reliability and economy of inductive power control
  • No moving parts or semi-conductors in the main power handling circuits
  • Transverse mode transient noise suppression.
  • Common mode transient noise suppression (optional)
  • Low internal impedance, capable of sustaining high surge currents.
  • Output accuracy of <0.3%
  • Stability maintained over the full range of input voltage variations, frequency variations and from zero to full load at any lagging power factor.
  • Fast response time
  • High efficiency.


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