Motor Nameplate Calculator

Calculate Full Load Amps, Torque, and Power from motor nameplate data

Motor Nameplate Calculator

Compliant with NEMA and IEC Standards

Results:

Full Load Amps (A): 0.00

Rated Torque (lb-ft): 0.00

Output Power (kW): 0.00

Input Power (kVA): 0.00

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How to Use the Calculator

AC Single Phase Motor

  1. Select "AC Motor" system type
  2. Choose "Single Phase"
  3. Enter Horsepower (HP)
  4. Provide Voltage (V)
  5. Input Efficiency (%)
  6. Input Power Factor (0-1)
  7. Enter Frequency (Hz)
  8. (Optional) Enter Rated RPM for Torque

AC Three Phase Motor

  1. Select "AC Motor" system type
  2. Choose "Three Phase"
  3. Enter Horsepower (HP)
  4. Provide Voltage (V)
  5. Input Efficiency (%)
  6. Input Power Factor (0-1)
  7. Enter Frequency (Hz)
  8. (Optional) Enter Rated RPM for Torque

DC Motor

  1. Select "DC Motor" system type
  2. Enter Horsepower (HP)
  3. Provide Voltage (V)
  4. Input Efficiency (%)
  5. Power Factor and Frequency are not applicable
  6. (Optional) Enter Rated RPM for Torque

Motor Nameplate Fundamentals

Motor Parameters

Motor nameplates provide crucial data for electrical and mechanical calculations:

  • Horsepower (HP): Mechanical output power
  • Voltage (V): Rated operating voltage
  • Efficiency (%): Ratio of output power to input power
  • Power Factor (PF): For AC motors, indicates phase difference between voltage and current
  • Rated RPM: Rotational speed at full load

Key Outputs

  • Full Load Amps (FLA): Current drawn at rated load
  • Rated Torque: Rotational force produced at rated load
  • Output Power (kW): Mechanical power in kilowatts
  • Input Power (kVA): Apparent power drawn by AC motor

Key Conversions:

1 HP = 746 Watts

1 kW = 1000 Watts

Calculation Formulas

Output Power (kW):
kW = HP × 0.746

AC Single Phase FLA:
FLA = (HP × 746) / (V × PF × Eff/100)

AC Three Phase FLA:
FLA = (√3 × V × PF × Eff/100)

DC Motor FLA:
FLA = (HP × 746) / (V × Eff/100)

Rated Torque (lb-ft):
Torque = (HP × 5252) / RPM

AC Input Power (kVA):
kVA = (FLA × V × √3 or 1) / 1000

Example Calculation

Three Phase AC Motor:

HP: 10 HP

Voltage: 480V

Efficiency: 90%

PF: 0.85

RPM: 1750

Output Power (kW) = 10 HP × 0.746 = 7.46 kW

FLA = (10 × 746) / (√3 × 480 × 0.85 × 0.90) ≈ 10.54 A

Torque = (10 × 5252) / 1750 ≈ 30.01 lb-ft

Input kVA = (10.54 × 480 × √3) / 1000 ≈ 8.76 kVA

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