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Power Factor

 

Power Factor Correction for
a Single, Three Phase Motor

Select horsepower, insert motor efficiency, select motor power factor
percentage, select desired power factor percentage. The required
kVAR is then displayed.



Select
hp
Insert
motor
efficiency
(Note 4)
 %
Motor
power
factor %
(Note 4)

Desired
power
factor %

The formula to calculate is: [("A" x 0.746) divided by ("B" divided by 100)] multiplied by "E" (which is the value from array of "C" and "D") = "F". "G" is the value from the range that "F" falls into which are the standard sizes of kVAR capacitors. ("C" divided by "D") multiplied by the nameplate FLA = corrected current amps.

  kVAR
blue dot
Overload current correction for motor used above
(Maintain previous values, insert nameplate FLA and press the calculate button.)
Nameplate FLA
 amps
Corrected current
  amps
Calculate

blue dot
Notes:
  1. If power factor correction is needed on a motor controlled by a variable frequency drive or a soft start, contact the device manufacturer for a solution.
  2. Do not try to overcorrect power factor. This can cause unintended problems that should be avoided.
  3. This calculator rounds down to the lower value for correct capacitor sizing.
  4. Full load power factor and efficiency data on the motor needing correction can be found in product data sheets, on the manufacturer's web site or from the motor's supplier.

 
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