How To Calculate Horsepower Of Electric Motor

Three-Phase Horsepower Formula:

\[ HP = \frac{V \times I \times \sqrt{3} \times Eff \times PF}{746} \]

Voltage (V):

Current (I):

Efficiency (Eff):

unitless

Power Factor (PF):

unitless

Horsepower (HP):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What Is Horsepower Calculation?

Horsepower calculation determines the mechanical power output of an electric motor from its electrical input parameters. It helps in motor selection, performance evaluation, and energy efficiency analysis for industrial and commercial applications.

2. How Does The Calculator Work?

The calculator uses the three-phase horsepower formula:

\[ HP = \frac{V \times I \times \sqrt{3} \times Eff \times PF}{746} \]

Where:

\( HP \) — Horsepower (output mechanical power)
\( V \) — Voltage in volts (V)
\( I \) — Current in amperes (A)
\( \sqrt{3} \) — Three-phase power constant (≈1.732)
\( Eff \) — Motor efficiency (unitless, 0-1)
\( PF \) — Power factor (unitless, 0-1)
\( 746 \) — Conversion factor (watts per horsepower)

Explanation: This formula converts electrical power input to mechanical power output, accounting for three-phase systems and motor efficiency losses.

3. Importance Of Horsepower Calculation

Details: Accurate horsepower calculation is essential for proper motor sizing, energy consumption analysis, system efficiency optimization, and preventing motor overload in industrial applications.

4. Using The Calculator

Tips: Enter voltage in volts, current in amperes, efficiency as decimal (e.g., 0.85 for 85%), and power factor as decimal. All values must be positive and within reasonable ranges for electric motors.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between electrical and mechanical horsepower?
A: Electrical horsepower refers to input power, while mechanical horsepower is the actual output power available at the motor shaft after accounting for efficiency losses.

Q2: Why is power factor important in horsepower calculation?
A: Power factor represents the phase difference between voltage and current. Lower power factors indicate reactive power consumption, reducing the actual useful power available.

Q3: What are typical efficiency values for electric motors?
A: Standard efficiency motors range from 85-90%, high-efficiency motors from 90-95%, and premium efficiency motors can exceed 95% efficiency.

Q4: Can this calculator be used for single-phase motors?
A: No, this calculator is specifically for three-phase motors. Single-phase motors use a different formula without the √3 factor.

Q5: How does motor size affect horsepower calculation?
A: Larger motors typically have higher efficiency and power factor values. Always use manufacturer specifications for accurate calculations in critical applications.