1. What is 3-Phase Motor Current?

The 3-phase motor current is the amount of electrical current required by a three-phase motor to produce a certain mechanical power output. It depends on the motor's power rating, supply voltage, power factor, and efficiency.

2. How Does the Calculator Work?

The calculator uses the 3-phase current formula:

Where:

• \( I \) — Current in amps
• \( P \) — Power in watts
• \( V \) — Line voltage in volts
• \( PF \) — Power factor (0-1)
• \( \eta \) — Motor efficiency (0-1)
• \( \sqrt{3} \) — Constant for 3-phase systems (~1.732)

Explanation: The formula accounts for all factors affecting current draw in a balanced 3-phase system.

3. Importance of Current Calculation

Details: Accurate current calculation is essential for proper wire sizing, circuit breaker selection, and overload protection in motor installations.

4. Using the Calculator

Tips: Enter power in watts, voltage in volts, power factor (typically 0.8-0.95), and efficiency (typically 0.85-0.95 for most motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's typical power factor for motors?
A: Induction motors typically have 0.85-0.95 PF at full load, lower at partial loads. Synchronous motors can achieve 1.0 PF.

Q2: How does voltage affect current?
A: Current is inversely proportional to voltage. Higher voltage systems require less current for the same power.

Q3: What if I know horsepower instead of watts?
A: Convert HP to watts (1 HP = 746 watts) before using the calculator.

Q4: Why include efficiency?
A: Motors convert electrical to mechanical power. Efficiency accounts for losses (heat, friction).

Q5: Is this for line or phase current?
A: This calculates line current in a balanced 3-phase system.