1. What is the Electric Motor Horsepower Formula?

Definition: This formula calculates the mechanical horsepower output of an electric motor based on its electrical input characteristics.

Purpose: It helps engineers and technicians determine motor performance and select appropriate motors for specific applications.

2. How Does the Formula Work?

The formula used is:

Where:

• \( HP \) — Horsepower output
• \( V \) — Voltage input (volts)
• \( I \) — Current draw (amps)
• \( \eta \) — Motor efficiency (0-1)
• \( PF \) — Power factor (0-1)
• 746 — Conversion factor (watts to HP)

Explanation: The formula converts electrical power (V×I) to mechanical power (HP) accounting for efficiency losses and power factor.

3. Importance of Motor Calculations

Details: Accurate motor calculations ensure proper equipment sizing, energy efficiency, and prevent overload conditions.

4. Using the Calculator

Tips: Enter the motor's voltage, current draw, efficiency (default 0.9), and power factor (default 0.85). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is motor efficiency?
A: The ratio of mechanical power output to electrical power input, typically 80-95% for good motors.

Q2: What is power factor?
A: The ratio of real power to apparent power, representing phase difference between voltage and current.

Q3: Why divide by 746?
A: 1 horsepower equals 746 watts, so we convert watts to HP.

Q4: Can I use this for three-phase motors?
A: For three-phase, multiply voltage by √3 (1.732) first before using this formula.

Q5: How do I find motor efficiency?
A: Check motor nameplate or manufacturer specifications, or use 0.85 as a typical estimate.