Motor Current Calculator (IEC)

Motor Parameters

Calculated Results

Full Load Current (IFLA) - A
Starting Current (Istart) - A
Apparent Power (S) - kVA

*Istart is an estimate based on typical multipliers:
DOL: ~6-7x | Star-Delta: ~2-3x | Soft Start: ~3x | VFD: ~1.2x

Technical Notes & Engineering Logic

Variable Definitions

  • Pout: Mechanical shaft power (kW or HP).
  • IFLA: Full Load Amperes at rated voltage/power.
  • η (Eta): Efficiency (Output Power / Input Power).
  • cos φ: Power Factor.

Formulas

  • 3-Phase IFLA: PW / (√3 × V × PF × η)
  • 1-Phase IFLA: PW / (V × PF × η)
  • Power Conv: 1 HP ≈ 746 Watts.
  • Apparent Power (S): √3 × V × I (3φ) / 1000 [kVA].

Assumptions

  • Calculations assume balanced 3-phase load.
  • Starting currents are screening values; consult manufacturer datasheets for exact locked-rotor amps (LRA).
  • Voltage is assumed to be Line-to-Line for 3-phase systems.
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