1. What is the 3 Phase HP to Amps Formula?

The 3-phase horsepower to amps formula calculates the electrical current required by a 3-phase motor given its power rating in horsepower. This is essential for proper circuit sizing and protection.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

Where:

• \( HP \) — Horsepower rating of the motor
• \( V \) — Line-to-line voltage (Volts)
• \( PF \) — Power factor (typically 0.8-0.95)
• \( Eff \) — Motor efficiency (typically 0.8-0.95)
• 746 — Conversion factor from HP to Watts

Explanation: The formula converts mechanical power (HP) to electrical power (Watts), then calculates current considering the 3-phase power characteristics.

3. Importance of Current Calculation

Details: Accurate current calculation is crucial for selecting proper wire sizes, circuit breakers, and overload protection devices to ensure safe and efficient motor operation.

4. Using the Calculator

Tips: Enter motor HP rating, system voltage, typical power factor (0.85 if unknown), and motor efficiency (0.90 if unknown). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why multiply HP by 746?
A: 746 watts equals 1 horsepower, so we convert mechanical power to electrical power equivalent.

Q2: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted to useful work.

Q3: What if I don't know the efficiency?
A: For most industrial motors, 0.90 (90%) is a reasonable estimate. Premium efficiency motors may be 0.93-0.96.

Q4: Does this work for single-phase motors?
A: No, single-phase motors use a different formula without the √3 factor.

Q5: How accurate is this calculation?
A: It provides a good estimate for full-load current, but actual current may vary based on load conditions and motor design.