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Voltage Stabilisers – Buyers Guide

Advice and guidance on how to ensure you select the most appropriate power protection system at a cost-efficient price.

If you are not familiar with choosing the right Power Protection system for your needs it can be a daunting and at times frustrating task. Over engineer the solution and it can be very expensive. Select a system that does not address all your identified power problems, or consider locally available resources, and you can so easily waste money.

For those unfamiliar in the selection process it is essential that you:

  • Know clearly your own requirements.
  • Know the right questions to ask of a potential supplier.
  • Know the advantages and disadvantages of the various design types

To assist in ensuring that you are ‘in the Know’, and as a result are able to choose the most appropriate and cost-efficient solution to solve your power quality problems, we offer advice and guidance on ten of the most frequently asked questions.

For electrical systems to function properly it is necessary to make sure that the quality of the power feeding them is of a sufficient quality to ensure that performance is not impaired or system life expectancy reduced.

Without the proper power, an electrical device or load may malfunction, fail prematurely or not operate at all. There are many ways in which electric power can be of poor quality and many more causes of such poor quality.

To indentify the most appropriate solution it is always recommended that you first identify exactly the problems you are experiencing. You may of course already have a good idea as to the problems being encountered. If not, it will be necessary to monitor the supply over a period of time to identify the types, duration and magnitude of power problems experienced.

Power supply problems are caused by various sources, for example distribution network faults, system switching, weather and environmental conditions, heavy plant and equipment, or simply faulty hardware.

Regardless of the cause of the problem, the resulting power quality issue will include one, or more, of the following power problems– checkout – Mains Voltage Supply Problems – Symptoms, Causes & Solutions

You will need to check the rating of the equipment to be protected. Such ratings are normally quoted in Amps or kVA, and whether single or three phase. You will also need to determine the nominal voltage line to neutral and line to line if three phase, plus the frequency and power factor.

Such information is usually shown on the rating plate attached to the equipment, otherwise you will need to consult the manufacturers of the equipment or take measurements. It is always recommended that you measure the loads true RMS value.

When determining the total power rating for the solution you require do not forget to allow for possible future expansion of the load you wish to protect over the medium to long term.

If you have a good idea as to the mains problems you are experiencing and the power requirements of the equipment you wish to protect you are in a very strong position to identify clearly the best and most cost efficient solution.

If you are experiencing all of the Power Quality issues identified in Question 2 an online UPS (Uninterruptible Power Supply) will often be viewed as the obvious choice. But be warned these are usually expensive to buy and have high ongoing maintenance and support costs. In many less developed countries the high technology skill sets required to maintain such systems are not readily and inexpensively available.

For most applications where the loss of mains is not really a critical issue, or can be accommodated by the use of a standby generator, the deployment of a Voltage Stabiliser or Power Line Conditioner will be a far more cost efficient solution both in terms of initial outlay, ongoing maintenance, support costs and the required local skill sets required to install, maintain and support the solution.

Be Warned – Over engineering a solution due to a lack of understanding on the power quality issues being experienced is an all too common mistake that can deeply impact your wallet!

One of the most common questions we get asked is what exactly is the difference between a Voltage Stabiliser and an AC Power Conditioner. In essence both protect against voltage transients, spikes, sags and brownouts, but an AC Power Conditioner also offers additional protection against Electrical Noise and higher level defence against transients and spikes. In most cases an AC Power Conditioner (Power Line Conditioner) is simply a Voltage Stabiliser with the inclusion of an isolation transformer. When a good earth cannot be provided ‘Common Mode’ Noise (E to L and E to N) can be a problem. With the inclusion of a shielded isolating transformer in a Power Conditioner, this interference will be suppressed to harmless levels. The output of an AC Power Conditioner is commonly referred to as a ‘Clean’ supply. As you would expect an AC Power Conditioner is normally more expensive than a Voltage Stabilizer / Regulator.

Choosing a stabiliser with the right input variation capability is important because if its input voltage range is exceeded, then its output will increase or decrease by the same amount by which it has gone “out of limit”.

In situations where there is a good mains supply, a stabiliser offering an input variation swing of ±15% (Our S15 models) will usually be more than acceptable, but in more remote locations, or countries where the national supply infrastructure is less developed, variations of ±20% or greater may be needed to be accommodated by the stabiliser.

As a general rule the greater the input voltage swing the stabiliser / conditioner needs to correct the greater the price.

An output voltage to within ± 1% / ±1.5% of the preset output voltage is the norm when specifying a Voltage Stabiliser or Power Conditioner. However if a lower output voltage accuracy can be accommodated by the load equipment, then the input voltage range can be extended proportionally. As the cost of the stabiliser is linked to the input voltage range it has to handle, accepting a lower output accuracy may prove to be a more economical solution.

With most supplies operating on 50 or 60 Hz, your normal mains supply frequency is unlikely to vary more than +/- 2%, and this is well within the capability of most stabilisers and conditioners. But if the supply is from a local generator it is possible that the frequency could deviate beyond this range and suitable protection should be considered to protect both the load and the power protection system.

Input Output Circuit Breaker: We recommend the specifying of an input or output Circuit breaker which, in addition to giving over current protection, will trip if the output / input deviates above or below a preset level. Certain models in our ranges are supplied as standard with input circuit breakers and on others the facility is available as an option.

Bypass Facility: You may also wish to consider fitting a bypass switch that will facilitate the inspection and maintenance by isolating the stabiliser and connecting your load directly to the mains supply. Certain models in our ranges are supplied as standard with an inbuilt bypass facility and on others we can supply suitable inbuilt or wall mountable external switches to requirements.

For the lay person, differentiating between the various technologies employed to deliver voltage stabilisation can often be a daunting task and it is not always clear as to which technology is best for a particular application.

As a leading manufacturer and supplier of Voltage Stabilizers and Power Conditioners we offer a wide cross section of alternative design types. Checkout – Design Topology Overview- for further details

With our strong and wide manufacturing base, Sinalda (UK) is able to meet the requirements of most Clients from our own in-house professional resources.

The sheer span of capability available from Sinalda (UK) tells its own story. Every power protection solution we offer is backed by the unrivalled experience our design engineers have gained in world markets over the last 40 years or so. In that time, their unique design innovations have set new performance levels. Today, the breadth of our offering continues to  broaden as we rise to accommodate the needs, and ever demanding requirements, of our growing Client base.

Our success is based entirely on our ability to meet the requirements of our Customers dependably and cost-effectively. Today, where performance is everything , whatever your AC mains supply problem Sinalda (UK) have the ability to offer a solution from our extensive range of standard and custom built products.