Watford Control Instruments Ltd
Watford Control is the true world leader in voltage control. We design and manufacture a comprehensive range of AC voltage stabilisers and Power Conditioners, which have been exported world wide since 1953.
All mains powered equipment requires a supply which is maintained within certain limits. Thus a low supply voltage will cause malfunction, whilst a high supply voltage will cause serious damage. Microprocessor based systems and other sensitive equipment requires not only a stable voltage but a supply free of transient spikes and electrical noise.
To meet all these demands, we design and manufacture an extensive range of AC Voltage Stabilisers and Power Conditioners covering ratings from 0.3kVA to over 8,000 kVA, both single and three phase versions.
The EM and EMS range offers the most cost effective and efficient way to ensure a stable, undistorted mains supply for the vast majority of applications.
Based on the proven electronic servo design, a double wound transformer has its secondary winding connected between the incoming AC supply and the load, with the primary winding voltage controlled by a motor-driven variable auto transformer. A solid-state servo amplifier continuously monitors the output voltage of the stabiliser, and any error voltage is amplified to operate the servomotor of the variable transformer, driving its brush-gear to a point where it is injecting a voltage that will correct the supply voltage by adding or subtracting from it.
Over six thousand models span ratings from 1kVA to 8,000kVA, single or three phase, incorporating full transient spike and noise suppression if required. Available with a wide selection of input voltage ranges from ±8% to ±40%
The BE range offers the advantage of true solid state, low distortion, inductive power control. Based on the original patented Watford twin tranductor design, providing the reliability of solid state control without the use of power semiconductors in the supply lines which can be easily damaged by voltage spikes or current surges, as is the case with solid state tap changers.
A twin transductor forms a potential divider across two taps of an input autotransformer, one side of which is connected to the load and the other to the incoming mains supply. A solid-state amplifier continuously monitors the output voltage across the load and this is compared against a highly stable reference voltage. Any error is amplified and directly coupled to the isolated control windings on 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 a low voltage and current levels.
Over two hundred models span ratings from 300VA to 860kVA output ratings, single or three phase, incorporating full transient spike and noise suppression fitted as standard.
Power saving by voltage optimisation
Primarily designed for markets that have a fairly reliable voltage supply, the Powersaver gives the user the chance to reduce electricity consumption and carbon output by up to 20%, literally overnight. A saving on electricity bills can be achieved by reducing the incoming supply voltage (242V average in the UK), to a more modest 220V or lower dependent on loads and optimising of the electrical supply.
The Powersavers advantage over any other method of voltage optimisation is that each phase is independently and linearly controlled to a site predetermined level. The adaptive control maintains this level, eliminating supply voltage fluctuations, allowing the full site potential savings to be achieved. Additionally, by balancing the phase voltages, direct drive motors will also improve their efficiency.
The Powersaver is supplied in a compact design ideal for retrofitting into existing switchgear rooms. Available with a number of correction ranges in either single and three phase to suit your particular site requirement and loadings up to 4,000kVA.
The DUOREG range of AC voltage stabilisers offer the proven reliability and essential features of the EM range, but at a considerably lower cost.
The units are supplied in attractive ventilated sheet steel enclosures to IP20. Models with ratings up to and including 13 Amperes are supplied with an output circuit breaker, 1.5m input cable and 3-pin output socket complete with plug. All other models above 13A are supplied suitable for "Hard wiring"
Single-phase models are available with rating up to 10kVA. For three phase operation, three single-phase units connected in "star" configuration will provide a very economical three-phase supply. Stabilising both line to neutral and line-to-line voltages to within +1% irrespective of phase balance.
The Iso-Tran consists of a transient noise suppressor and isolation transformer to provide transverse mode and common mode noise attenuation when there is no requirement for voltage stabilisation.
The units are supplied in attractive ventilated sheet steel enclosures to IP20. Models with ratings up to and including 13 Amperes are supplied with an output circuit breaker, 1.5m input cable and 3-pin output socket complete with plug. All other models above 13A are supplied suitable for "Hard Wiring" to terminals within the enclosure.
Rotavolt Variable Auto-Transformers provide a continuous linear regulation of AC voltage, with high efficiency and negligible waveform distortion. It offers a precise and effective method of controlling current, light, heat, motor speed and any parameter with a voltage factor.
Single and three phase models come in 9 frame sizes and rating up to 60kVA. Motorised versions available for remote or automatic operation.