1. What is a 3-Phase HP to Amps Calculator?

Definition: This calculator converts horsepower to electrical current (amps) for three-phase motors.

Purpose: Helps electricians and engineers properly size electrical components for motor installations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I \) — Current in amps
• \( HP \) — Motor horsepower
• \( V \) — Voltage (line-to-line)
• \( \eta \) — Motor efficiency (0-1)
• \( PF \) — Power factor (0-1)
• 746 — Conversion factor (1 HP = 746 watts)

Explanation: Converts mechanical power to electrical power, accounting for motor efficiency and power factor in 3-phase systems.

3. Importance of Current Calculation

Details: Accurate current calculation ensures proper wire sizing, circuit breaker selection, and prevents equipment damage.

4. Using the Calculator

Tips: Enter motor HP, system voltage (default 480V), motor efficiency (default 0.9), and power factor (default 0.85). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is 746 used in the formula?
A: 746 watts equals 1 horsepower, converting mechanical to electrical power.

Q2: What's a typical power factor for motors?
A: Most motors have PF between 0.8-0.9, but check manufacturer specs.

Q3: Where do I find motor efficiency?
A: Motor nameplate or manufacturer documentation. Modern motors are typically 85-95% efficient.

Q4: Does this work for single-phase motors?
A: No, use a different formula (remove √3 factor) for single-phase.

Q5: Should I add a safety factor?
A: Yes, consider multiplying result by 1.25 for continuous duty applications.