Basic Formulas

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BasicFormulasThefollowingpagesofformulas,somederivationsanddiscussionsareintendedtoassistindesigningandapplyingcapacitorbanksproperly.Also,refertoCapacitorBankInrushCalculationsforadditionalinformation.

1.Ohm’sLaw

ThiswillallowyoutodeterminethereactanceofacapacitororreactorwhenvoltageandKVARisgiven.

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304-252-6243•www.elginpowersolutions.com

Example:Athree-phase600KVARcapacitorbankat12,470willyield

Xc= = =259.168OhmsAthree-phaseshuntreactorof150KVAR,at13.8KVwillyield

Xc= = =1269.6Ohms

2.Capacitance

Example:Fromabove600KVARat12.47KVequals259.168Ohmsandfrom(12)

XC= .ThenC=

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304-252-6243•www.elginpowersolutions.com

Letf=60Hertz ThenC=0.000010235faradsor10.235microfarads.

From(16)KVAR= KVAR=600

3.Inductance

Fromabove150KVARat13.8KVequals1269.6Ohmsandfrom(17)

.Letf=60Hertz

ThenL= = =3.36773HenriesOr3367.73millihenries.

From(19)KVAR= = KVAR=150

214IndustrialParkRoad,Beaver,WestVirginia25813

304-252-6243•www.elginpowersolutions.com