Motor HP to Amps Calculator

Calculate motor current from horsepower for AC/DC systems

Motor HP to Amps Calculator

Compliant with NEMA Standards

Results:

Current (Amps): 0.00

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How to Use the Calculator

AC Single Phase

  1. Select "AC" system type
  2. Choose "Single Phase"
  3. Enter motor Horsepower (HP)
  4. Provide line-to-neutral voltage
  5. Input Power Factor (0-1)
  6. Input Efficiency (0-100%)

AC Three Phase

  1. Select "AC" system type
  2. Choose "Three Phase"
  3. Enter motor Horsepower (HP)
  4. Provide line-to-line voltage
  5. Input Power Factor (0-1)
  6. Input Efficiency (0-100%)

DC Systems

  1. Select "DC" system type
  2. Enter motor Horsepower (HP)
  3. Provide voltage
  4. Power factor and efficiency are not applicable

Motor HP to Amps Fundamentals

AC Motor Current

For AC motors, current calculation depends on:

  • Phase configuration (Single/Three)
  • Power factor (cosφ)
  • Motor Efficiency
  • Voltage type (Line-to-Line/Line-to-Neutral)

DC Motor Current

  • Simpler calculation based on HP and Voltage
  • No phase, power factor, or efficiency considerations
  • Direct conversion from mechanical power to electrical current

Key Formulas:

DC: Amps = (HP × 746) / V

AC Single Phase: Amps = (HP × 746) / (V × PF × Eff)

AC Three Phase: Amps = (HP × 746) / (√3 × V × PF × Eff)

Note: 1 HP = 746 Watts

Calculation Formulas

DC Systems:
Amps = (HP × 746) / V

AC Single Phase:
Amps = (HP × 746) / (V × PF × Eff)

AC Three Phase:
Amps = (HP × 746) / (√3 × V × PF × Eff)

Example Calculation

Three Phase AC Motor:

Horsepower (HP): 10 HP

Voltage: 400V

Power Factor (PF): 0.85

Efficiency (Eff): 90% (0.9)

Amps = (10 × 746) / (√3 × 400V × 0.85 × 0.9)

Amps = 7460 / (1.732 × 400 × 0.85 × 0.9)

Amps = 7460 / 530.424 ≈ 14.06 Amps

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