B25 series automatic capacitor banks

B25 series THDi ≤ 25%

Industrial plants where the load varies greatly throughout normal operation will require automatic P.F. equipment in order to connect the necessary capacitive power. 

More details

Technical data

  • Rated voltage: 400Vac
  • Rated frequency: 50Hz (60Hz on request)
  • Voltage of auxiliary circuits: 110Vac
  • Working temperature range: -10°C/+50°C
  • Cubicle: 20/10mm sheet steel, protected against corrosion by a phosphating treatment. Epoxy powder painted, RAL 7035 color (other colors on request) External Protection Degree: IP30 (type S-M), IP40 (Type L) Locking system: by screw for cubicle type S and type M type by key for cubicle type L
  • Ventilation: Forced
  • Isolating switch: Three-pole with door interlocking device
  • Supplying: Type S: entry of the cable from the top/bottom Type M: entry of the cable from the top Type L: entry of the cable from the bottom
  • Wiring: By N07VK CEI 20-22 flame retardant cables. Auxiliary circuits are identified as in the electrical drawing
  • Contactors: Each capacitor banks is controlled by a three-pole contactor. To limit the overcurrent peaks, each contactor is provided with insertion resistors. Rated voltage of auxiliary circuits: 110 Vac, 50 Hz.
  • Fuses: Each capacitor banks is protected by a set of three fuses (NH00 type) with high breaking capacity. Also the auxiliary circuits are protected by fuses.
  • Capacitors B25 440 Vac Series Single phase of type self-healing, made up of metalized polypropylene, equipped with overpressure safety device and discharge resistor. Filling: biodegradable non toxic dry type, PCB free. Manufactured using new technologies of metallization. Delta connection. Capacitance tolerance: -5% +10% Dielectric losses: <0.3W/kvar Temperature class: -25°C (55°C)
  • Regulators: Varmetric measurement by means of a C.T. (Current Transformer)(secondary 5A) not supplied
  • Reference Standards: Complying with: L.V. 73/23 (93/68) EEC Directive Capacitors: CEI EN 60831-1/2 Equipments: CEI EN 60439-1, CEI EN 61921-1
  • Options (on request): Automatic switch Isolator with fuses Protection degree : IP55 Type M: entry of the cable from bottom Type L: entry of the cable from the top

Power Factor Correction in presence of harmonics

In recent years, Power Factor Correction has evolved greatly due to the presence of generated harmonics by the loads. These loads produce harmonic currents and voltage which distorts the network waveforms. The main sources of harmonics are generated by AC/DC static converters and UPS systems. For these reasons it is essential that any installation of Power Factor Correction equipment must be carefully evaluated. The possible presence of harmonic currents in the network could create conditions of parallel resonance between the inductance of the network and the capacitors, generating overcurrents and overvoltages, which would cause premature failure of the power factor correction capacitors. The ideal power factor correction solution for any system must be determined by examination of the system parameters and harmonic spectrum.

Power factor correction

Level of current harmonic distortion allowed in the equipment

THDiC % on the capacitorsTHDIi % on the networkCapacitor banks
≤ 25≤ 10*B25PF/R
≤ 35≤ 15*B35PF/S
≤ 50  ≤ 20*B50PF/XS
≤ 85≤ 50**AR180PF/A
≤ 100  ≤ 100**AR140PF/HA

The new RAUNI regulators are equipped with alarm threshold, which disconnects the equipment if the ALARM THDi is exceeded. Equipments with blocking inductance have this threshold detection disconnected because there is no resonance risk. * Resonance not allowed ** THDv max 6%

Network: 400Vac 50Hz THDi ≤10%

Resonance non allowed

Capacitors: 440Vac 50Hz, THDi ≤25%


WxDxH, mm


kVAR at 400V

Power of banks




Isolating switch








kVAR at 415V

B25PFSR-13 460x215x480131,875-3,75-7,5763RAUNI96181214
B25PFSR-18.5 460x215x48018,53,75-7,5-7,5563RAUNI96261320
B25PFSR-20.6 610x215x48020,61,875-3,75-7,5-7,51180RAUNI96301622
B25PFSR-26 460x215x480263,75-7,5-15763RAUNI96371428
B25PFSR-30 460x215x480307,5-7,5-15463RAUNI96431532
B25PFSR-35 610x215x480351,875-3,75-7,5-7,5-1519100RAUNI96502237,5
B25PFSR-37.5 460x215x48037,57,5-15-155100RAUNI96541640
B25PFSR-45 610x215x480457,5-7,5-15-156100RAUNI96652348
B25PFSR-52.5 610x215x48052,57,5-15-15-157125RAUNI96762456,5
B25PFSR-60 610x215x480607,5-7,5-15-308160RAUNI96862765
B25PFSR-67.5 610x215x48067,57,5-15-15-309160RAUNI96972972,5
B25PFMR-75 420x380x700757,5-15-22,5-3010250RAUNI961084180
B25PFMR-105 420x380x9201057,5-15-22,5-30-3014250RAUNI9615147112
B25PFMR-127.5 420x380x920127,57,5-15-22,5-30-52,517400RAUNI9618451138
B25PFMR-150 420x380x92015015-30-45-6010400RAUNI9621654162
B25PFMR-180 420x380x114018015-30-60-7512400RAUNI9625960194
B25PFMR-195 420x380x114019515-30-60-9013500RAUNI9628165210
B25PFMR-225 420x380x114022515-30-60-12015500RAUNI9632469242
B25PFLR-255 610x610x176025515-30-30-60-60-6017630RAUNI144367260275
B25PFLR-300 610x610x176030030-30-60-60-60-6010800RAUNI144432270322
B25PFLR-375 610x610x176037537,5-37,5-75-75-75-7510800RAUNI144540280404
B25PFLR-450 610x610x176045045-45-90-90-90-90101000RAUNI144648300484
B25PFLR-525 610x610x196052552,5-52,5-105-105-105-105101250RAUNI144756340565
B25PFLR-600 1220x610x176060060-60-120-120-120-120102x800RAUNI144864560646
B25PFLR-675 1220x610x176067567,5-67,5-135-135-135-135102x800RAUNI144972640726
B25PFLR-750 1220x610x176075075-75-150-150-150-150102x1250RAUNI1441080660807
B25PFLR-825 1220x610x176082582,5-82,5-165-165-165-165102x1250RAUNI1441188700888
B25PFLR-900 1220x610x176090090-90-180-180-180-180102x1250RAUNI1441296720968
B25PFLR-975 1220x610x196097597,5-97,5-195-195-195-195102x1250RAUNI14414047601049
B25PFLR-1050 1220x610x19601050105-105-210-210-210-210102x1250RAUNI14415128001130