We use our own and third-party cookies to improve browsing and provide content of interest.

In continuing we understand that you accept our Cookies Policy. You can modify the cookies storage options in your browser. Learn more

I understand




For many years now, power factor correction has been one of the first steps to improving the energy efficiency of installations. Since their beginnings, compensation techniques have grown and developed over the years, adapting to new needs (basically the types of loads that must be compensated) and to new technologies that have become available.

At first, the most common compensation technique was to use capacitor banks with contactor operation. This compensation system is optimal for balanced systems and to compensate loads with connection and disconnection rates that are not too fast, on the order of seconds, and it is currently the most common system in most installations despite increasing numbers of unbalanced installations.

The passage of time and the growing use of more dynamic loads in many installations has led to the emergence of a new technique: the use of static contactors (solid-state relays or thyristors) to operate the capacitors in a capacitor bank. This technique has a set of important advantages over compensation with contactor operation:

  • Response speed: the use of thyristors enables compensation in installations with highly fluctuating load variations (in cycles, on the order of ms), making it the optimal solution for cosφ correction of very fast loads. The paradigmatic case would be the compensation of welds, although lifts, freight elevators, compressors, etc. would also be on the list of likely loads.
  • Elimination of mechanical wear: contactors have a limited mechanical life, which incurs the need for regular maintenance to ensure the capacitor bank is functioning properly. The use of thyristor operation eliminates this need, extending the useful life of the capacitor bank assembly and reducing maintenance costs.
  • Less noise: the use of electronics during contactor operation eliminates mechanical noises generated by the contactors, which can become an annoyance in service installations.
  • Elimination of connection transients: the use of zero switching control boards ensures the elimination of transients when the capacitor connects, giving it a longer useful life and eliminating disturbances on the electrical network.

In the early days of this new technology its main drawback was its high price, which meant that investing in this type of unit necessitated long repayment periods for most companies, making it difficult to justify the expenditure, even more so if compared to traditional compensation with contactors.

FO OPTIM EMS-C 250x250

CIRCUTOR was a pioneer in developing the technology used in static capacitor banks and has included them in its catalogue for more than 20 years, making the company a leader in this technique within the electricity market. In recent times, significant R&D efforts have been made to adapt the new emerging technologies to this compensation technique, developing a new range of static capacitor banks that drastically reduce the price difference between the two compensation systems (contactors / thyristors), thus eliminating the main obstacle to choosing a static capacitor bank as a compensation method.

To this end, CIRCUTOR has launched the new range of EMS-C static capacitor banks which are ideal for industrial applications, such as arc welding, compressor start-up, cranes and hoists. But they are also suitable for the service sectors, such as compensating lifts in communities of residents, given that the traditional contactor technique does not compensate them well due to their quick input and output rate.

Thanks to minimising the cost difference between classic compensation with contactors and advanced static compensation, CIRCUTOR has turned the choice of a static capacitor bank from a technical whim to a tangible reality within the reach of all budgets.


More information about 低压自动补偿电容柜


Documentation about Automatic capacitor banks


您也可以关注我们的公众账号CIRCUTOR的 Twitter账号, 以及LinkedIn.



Vial Sant Jordi s/n, 08232
Viladecavalls (Barcelona) Spain
Tel: (+34) 93 745 29 00
Fax (+34) 93 745 29 14


(+34) 93 745 29 19