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Power factor correction calculator: capacitor bank size

Capacitor bank rating in kvar to raise the power factor, Qc = P·(tan φ1 − tan φ2), with apparent power before and after correction. Free, no sign-up.

  • Instant result
  • Formula and standards shown
  • On desktop and phone

Pre-filled example

A 100 kW installation at a power factor of 0.8, to be raised to 0.95.

kW

Result

42.13kvarCapacitor bank Qc

Apparent power before
125.0kVA
Apparent power after
105.3kVA
Attach this calculation to a work order

Free during the beta, no credit card

Capacitor bank sizing kept with the installation

Here, the calculator is free and the result is gone when you close the page. In Reglova, it is attached to the work order on the right machine: you find it again at the next breakdown, and on audit day.

The CMMS software comparison, our gaps included
  • Attached to the work order with its inputs: the server recalculates it, it stays verifiable.
  • On the technician's phone, even without a network.
  • In the machine's history, for the next breakdown.
  • The asset's nameplate data pre-fills the calculation.
Try the demoJoin the free beta
Reglova · Calculations · Work order WO-AT01-04219
Silent video, 33 s: from the work order for an oil leak on a shear cylinder, the tightening torque of an M12 bolt, then "Attach to the work order". A step to tighten it to 93.1 N·m lands in the checklist (step text from the French demo data). Watch the video

When to correct the power factor

  1. 01

    Size a capacitor bank before asking for a quote.

  2. 02

    Free up capacity on a transformer close to its limit.

  3. 03

    Check that an existing bank is still enough after adding motors.

Good to know

With variable speed drives on the network, harmonics often call for a detuned capacitor bank with reactors: check with the supplier.

Power factor correction formula: Qc = P·(tan φ1 − tan φ2)

Raising the power factor reduces the apparent power drawn, and so the current in the cables and the transformer. The calculator gives the capacitor bank rating, Qc = P·(tan φ1 − tan φ2), and the apparent power before and after correction.

Formula · Reference documents

Qc = P·(tan φ1 − tan φ2)

Electrical engineering ; Schneider Electric guide, reactive energy compensation

Inputs and accepted ranges
InputUnitAccepted rangeExample
Active power PkW0.01 to 100,000100 kW
Current cos φ0.01 to 10.8
Target cos φ0.01 to 10.95
Calculated results
  • Capacitor bank Qckvar
  • Apparent power beforekVA
  • Apparent power afterkVA

Capacitor banks and switchboards inspected on schedule

  • Breakdowns reported by QR code
  • Work orders on the phone, even without a network
  • Mandatory inspections reminded by email
  • Audit file as a PDF, in one click
Try the demoJoin the free beta

Free during the beta, no credit card