1. What is Motor Horsepower?

Horsepower (HP) is a unit of measurement for power, representing the rate at which work is done. For electric motors, it indicates the mechanical output power based on electrical input and efficiency.

2. How Does the Calculator Work?

The calculator uses the horsepower formula:

Where:

• \( V \) — Voltage in volts
• \( I \) — Current in amps
• \( PF \) — Power factor (unitless, 0-1)
• \( \eta \) — Efficiency (decimal, 0-1)
• 746 — Conversion factor from watts to horsepower

Explanation: The formula calculates the mechanical power output by accounting for electrical input (V × I), power factor (PF), and motor efficiency (η).

3. Importance of Horsepower Calculation

Details: Accurate horsepower calculation is essential for proper motor sizing, energy efficiency assessment, and mechanical system design.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, power factor (typically 0.8-0.95), and efficiency (typically 0.8-0.95 for most motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between input and output horsepower?
A: Input HP is electrical power (watts) divided by 746. Output HP is mechanical power after accounting for efficiency losses.

Q2: Why is power factor important?
A: Power factor accounts for phase difference between voltage and current in AC circuits. Lower PF means more current is needed for the same real power.

Q3: What are typical efficiency values for motors?
A: Small motors: 70-85%, Medium motors: 85-92%, Large motors: 93-97%. Efficiency decreases with underloading.

Q4: Can I use this for three-phase motors?
A: For three-phase, multiply by √3 (1.732) for line-to-line voltage measurements.

Q5: How does motor speed affect horsepower?
A: At constant torque, HP increases with speed. Motor ratings specify HP at rated speed (usually 1750 or 3500 RPM for 60Hz systems).