Ecostab

Ecostab
Energy Saving System 

automatic voltage optimisers

are one of the solutions offered by new technologies to users.
These devices comply with the requirements of

IEC 60038

for electric equipment operating tolerances and supply an operating voltage which minimises consumption without impairing performance or reducing reliability.
IEC 60038 establishes that the electric equipment must be able to work correctly at an input voltage within ±10% of the nominal value, that is from 253V to 207V for single-phase devices and from 440V to 360V for three-phase devices.
This is an essential feature for all electric devices because

energy

producers establish that the supplied voltage may vary within these limits contractually.
As a consequence, if a load is supplied at a value close to the lower operating tolerance limit (-8%) also when the mains voltage assumes the higher value established by contract (+10%), the difference between 253V and 207V in absolute terms is 18%.

This power supply difference allows to:

1. a) obtain a significant saving of energy;
   b) Extend the working life of electric equipment. Ecostab voltage optimisers prevent devices from being powered at higher values than the rated voltage. For example, it is a known fact that the life of sodium bulbs is reduced by 50% when they are powered at a voltage 10% higher than their rated value;
   c) Secure a significant reduction of carbon dioxide emissions. This corresponds to approximately 630 g for every saved kWh of energy.

Ecostab automatic voltage optimisers deliver a stabilised voltage which can be set to the minimum tolerance established in IEC 60038, i.e. -8% (212V). This value is guaranteed also in presence of significant mains voltage variations. Interestingly, these devices are also excellent mains voltage stabilisers.

• Standard single-phase modelscan deliver a variable voltage from 230V to 212V with input voltage comprised in the 207-253V range.
• Standard three-phase modelscan deliver a variable voltage from 368/212V to 400/230V with input voltage comprised between 360/207V and 440/253V.

Models capable of broader input voltage variations may be built on demand. These may be needed because voltage may sometimes exceed the 10% tolerance specified in the supply contract.

Saving and return on investment

There are many factors which contribute to saving energy and reduce the payback period:

• Mains voltagewhich is not always close to rated value. Voltage is usually higher late at night: 10% higher than the rated value is a common condition. This level is often exceeded when the user is located near an electric substation. Saving increases to approximately 20% when the voltage exceeds 10% of the rated value.
• Type of powered device. Some devices allow higher saving than others and some electric devices do not provide any significant saving at all.
• Device use.The best results are obtained by using Ecostab in connection to motors with stall torque often lower than the maximum deliverable torque.
• Overall consumption of devices powered by the voltage optimiser.The higher the power of the Ecostab voltage optimiser, the shorter its payback period.

Since not all the appliances and loads ensure the same saving, a careful analysis on their use is necessary to predict potential saving.

Sometimes, it may be advantageous to limit the use of Ecostab voltage optimisers to some devices to optimise the investment.

The cost of the voltage optimiser will be usually paid off by the saved energy in a period ranging from two to five years.

Operating principle

An electronic control circuit detects the voltage delivered by the voltage optimiser and compares it to a reference voltage. If the difference between the output voltage and the reference voltage exceeds the preset tolerance limits, an error signal is generated; this signal may be either negative or positive according to whether the output voltage is lower or higher than the preset value. This signal activates the servomotor which moves the mobile contacts (electrographite rollers / brushes) of the variable autotransformer thus changing the transformation ratio in order to supply the additive or subtractive voltage needed to restore the value within the predetermined limits to the primary winding of the series transformer. The root-mean-square value (RMS) of the output voltage is stabilised and consequently not affected by possible harmonic distortions present in the input mains. This regulation system has the advantage of not having mobile contacts in series to the power supply line.