# The Basic Power Calculation

The first thing we need to know is about 1KW = 1000W or 1KA = 1000A

Single Phase Power

– KW = (Volts x Amps x PF)/1000

Three Phase Power

– KW = (Volts x Amps x PF x 1.73)/1000

Example: our device show 8.5A and 380V, then we calculate the KW? we know the Power Factor (PF) in the rang 0.8 to 0.95 refer to the device. right now we choose PF equals 0.85.

Answer is KW = (380 x 8.5 x 0.85 x 1.73)/1000 = 4.74 kW, so your device need power 4.74KW

**KVA Calculator**

*Single Phase*

– KVA = (Volts x Amps) / 1000

Three Phase

– KVA = (Volts x Amps x 1.73) / 1000

Other thing of the **Unity Power Factor**

– Power (Watts) = Volts x Amps

– Power (Watts) = I²R

– Power (Watts) = V²/R

AC Efficiency and Power Factor

*Single Phase*

– Efficiency = (746 x HP) / (E x I x PF)

– Power Factor = Input Watts / (V x A)

*Three Phase*

– Efficiency = (746 x HP) / (E x I x PF x 1.732)

– Power Factor = Input Watts / (E x I x 1.732)

**Ohm’s Law** defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It’s the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a large amount of current to flow. Resistance is measured in ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.

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