Three phase and single phase power

Calculate kVA and kW from voltage, current and power factor for single phase or three phase loads, with electrical input HP and optional shaft HP.

What this means

kVA is apparent power; kW is real power after power factor. Electrical input horsepower is kW ÷ 0.746. Shaft output horsepower is lower because of motor losses, so it needs the motor efficiency.

Formula used

  • Three phase kVA = √3 × V × I ÷ 1000
  • Single phase kVA = V × I ÷ 1000
  • kW = kVA × power factor
  • Input HP = kW ÷ 0.746
  • Shaft HP = input HP × efficiency

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