1. What is the 3 Phase Motor HP to Amps Calculation?

The 3 Phase Motor HP to Amps calculation determines the current drawn by a three-phase electric motor given its horsepower rating, voltage, efficiency, and power factor. This is essential for proper circuit sizing and protection.

2. How Does the Calculator Work?

The calculator uses the 3-phase current formula:

Where:

• \( I \) — Current in amperes (A)
• \( HP \) — Motor horsepower (hp)
• \( V \) — Line voltage (V)
• \( eff \) — Motor efficiency (0-1)
• \( PF \) — Power factor (0-1)
• 746 — Conversion factor from hp to watts

Explanation: The formula converts horsepower to watts, then calculates current considering the three-phase power factor and motor efficiency.

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 motor operation.

4. Using the Calculator

Tips: Enter motor horsepower, line voltage, efficiency (typically 0.8-0.95), and power factor (typically 0.8-0.95). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use 746 in the formula?
A: 746 watts equals 1 horsepower, so this converts mechanical power (hp) to electrical power (watts).

Q2: What's typical motor efficiency?
A: Standard efficiency motors range from 80-95%, with higher hp motors generally more efficient.

Q3: How does voltage affect current?
A: Current is inversely proportional to voltage - higher voltage means lower current for the same power.

Q4: What if I don't know the power factor?
A: Use 0.85 as a reasonable estimate for most industrial motors under load.

Q5: Does this work for single-phase motors?
A: No, single-phase motors use a different formula without the √3 factor.