# POWER FACTOR

On a balanced 3 phase given kw and V:
To find Current: (kW x 1000) / (E x PF) = amps
I have a 208v, 50/60Hz, 9kW, 3 PH
kw=9 E 8 PF=???
I know PF = cos(theta) or PF (3 PH) = Input Watts / (E x I x 1.732)
I am trying find the current?? I'm I doing something wrong? Because I thought PF has to be between 0 and 1.
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remove the X to answer
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For motor, transformer, and other inductive laods assume a power factor of about 0.7 to 0.8 For resistive loads assume a power factor of 1.0 Now you can find the amperes.
Power (in watts) = E x I x 1.732 x PF for three phase.
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So to correct a 240v 3600W isolation transformer at say 0.8, I should use a capacitor of ??? ufd??
TVMIA
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Power factor correction for a lagging power factor is seldom done in for normal field installations, especially for small loads. Transformers are usually rated in volt ameres because the power factor is not know at time of manufacturer.
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Gerald Newton wrote:

Transformers are rated in VA because that determines the maximum current through the winding. The load watts don't matter to the transformer. In other words, a one kVA transformer could deliver one kVA to a one kVAR capacitor that draws zero watts, or to a heater that draws one kW. It is fully loaded either way.
Ben Miller
--
Benjamin D Miller, PE
www.bmillerengineering.com
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Let us know when the cos (x) of any angle is greater than 1.
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