Static Power Factor Correction equipment differs from the standard equipment for the following reasons:

 The reactive power regulator has a switching time of the banks extremely quicker than the standard regulator

 The device for switching the capacitors banks is electronic, controlled by thyristors, with the capability of switching the capacitors at zero crossing.

Static switching by thyristors has the following advantages:

 Maximum speed in switching the capacitors banks (the total power is switched in less than a second)

 No current peak on the capacitors at the time of switching of the banks

 No voltage peak on the capacitors at the time of switching off the banks

 Elimination of  deterioration of the contacts in the standard contactors

 Noise reduced to a minimum

 Reduced maintenance

 Prolonged capacitor life.



The automatic static Power Factor Correction is particularly suitable for variable quick loads, such as:

 Injection presses


 High torque motors

 Motors affected by voltage losses

 Car industry

 Wind turbines for the production of electric energy

 Diesel generators 



400 Vac  50 Hz 

Blocking Reactors 180 Hz

Capacitors 550 Vac 50 Hz

THDImax < 50%




400 Vac  50 Hz 

Blocking Reactors 180 Hz

Capacitors MFHC 460 Vac 50 Hz 3 In

THDImax < 60%


Other models upon request





Rated voltage of Power Factor Correction Equipment is the voltage for which the equipment has been designed.

To ensure that premature failure of the equipment is eliminated, the operating voltage should not be greater than the rated voltage.

The overvoltage limits allowed are shown in the following table in accordance to CEI EN 60831-1 Standards:


Voltage factor x Un


Maximum duration


Power frequency



Highest average value during any period of capacitor energization.

For energization period less than 24 h, exceptions apply.

Power frequency


8 h in every 24 h

System voltage regulation and fluctuations.

Power frequency


30 min. in every 24 h

System voltage regulation and fluctuations.

Power frequency


5 min.

Voltage rise at light load.

Power frequency


1 min.

- - -

Anyhow, the use of  P.F.C. Equipment in conditions of overvoltage causes a reduction of the life.



Working temperature is a fundamental parameter for the safe functioning of Power Factor Correction Equipment. Consequently, it is very important to have sufficient heat dissipation inside the Power Factor Correction Equipment cubicle. Ventilation should be adequate to prevent the temperature rise exceeding the limits of the capacitor design.

The capacitors are designed in accordance to CEI EN 60831-1 Standards and the limits of temperature rise are prescribed within this document:

Symbol Ambient Temperature
Maximum Highest mean over any period of:
24 h 1 year
A 40C 30C 20C
B 45C 35C 25C
C 50C 40C 30C
D 55C 45C 35C

In hot weather, it is advisable that ventilation and/or air-conditioning are fitted where the Power Factor Correction Equipment is installed. Exceeding of the temperature limits prescribed could reduce the life of the  Power Factor Correction Equipment.


Choice of P.F.C. equipment in presence of non-linear loads

The ever-increasing use of static converters, rectifiers and other generators of harmonic current and voltage distortion on the supply network make it essential to carefully evaluate the installation of Power Factor Correction equipment in order not to create a resonance condition, which amplifies overcurrent and overvoltage, becoming dangerous for the capacitors and other connected loads.

The choice of the right Power Factor Correction equipment is related to the power of the non-linear loads and the power rating of the transformer.

ITALFARAD proposes a complete range of Power Factor Correction  equipment which can meet all these demands. Our experienced Technical Department is at the disposal of the customers for advising about the best possible solution.


ITALFARAD S.p.A.  via IV novembre, 1   40061 Minerbio   Bologna   Italy

Telefono: ++39 051 6618311   Fax: ++39 051 6605594   E-mail: italfarad@italfarad.com

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