POWER · CALCULATOR

Capacitor power at a different voltage

Free capacitor power at a different voltage: get reactive power at operating voltage from rated reactive power, rated voltage and operating voltage.

Written by Chameera Sampath · Not yet reviewed by a licensed electrician. See the methodology.

US (NEC) only · NFPA 70 / NEC — locally adopted editionDefaults are US values. Verify the locally adopted NEC edition and project data.Official reference ↗

Project inputs

Measurements

Rated reactive power

kvar

Rated voltage

Operating voltage

Updates as inputs change. Unit changes preserve the same physical values.

THE MATH BEHIND THE ANSWER

Method & assumptions

Q2 = Q1 × (V2/V1)²

Same frequency. Never exceed capacitor voltage rating.

Results do not check every aspect of an electrical installation. The calculators follow US (NEC) practice only; a regional preset changes defaults such as voltage and units, and no result certifies NEC compliance.

Sources and validation →

Worked example

Rated reactive power: 10 kvar · Rated voltage: 480 V · Operating voltage: 460 V

Reactive power at operating voltage: 9.184 kvar

This example uses the stated inputs; results for the entered values appear above.

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