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# How do you calculate cos phi -1?

Updated: 12/19/2022

Wiki User

12y ago

cos(phi - 1) = cos(phi)cos(1) + sin(phi)sin(1)

Wiki User

12y ago

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Q: How do you calculate cos phi -1?
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Because it has to be 1 when the phase angle is zero.

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3 phase kVA = V*I*sqrt(3) Where voltage is line to line, and current is the actual RMS current flowing in the a wire. kW = V*I*sqrt(3)*Cos (phi), where phi is the angle between the voltage and current; Cos (phi) is also known as the power factor. kVA is the vector sum of kW (real power) and kVAR (reactive power). As the equations above suggest, you must know the voltage to correctly calculate the current.

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The formula to calculate split times is given by percent of time= (2-4*phi)* (percent of distance) ^2 + ((4*phi)-1) *percent of distance). Positive splits and negative splits are the two types of splits.

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The power factor for a three phase generator is 80 percent. The generator consumes 36 kilowatts and a line to line voltage of 400 volts.