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Generator Calculator

Calculate generator load current and fault current contributions for proper sizing and protection coordination.

Generator Load Current Calculator

Calculate generator output current based on load power requirements and operating conditions.

Typical: 0.8 lagging for generators

Generator Sizing Notes

  • Generators are typically rated at 0.8 power factor lagging
  • Motor starting loads may require larger generator (3-6× motor FLA)
  • Altitude and temperature affect output - derate above 3300 ft or 77°F
  • Size for continuous loads at 100% + largest motor at 25% of FLA
  • Consider harmonic loads - may require oversizing by 20-50%