1. What is 3-Phase Motor Current?

The 3-phase motor current is the amount of electrical current drawn by a three-phase electric motor when operating under load. It's crucial for proper circuit sizing and protection.

2. How Does the Calculator Work?

The calculator uses the 3-phase current formula:

Where:

• \( Power \) — Motor power rating in kilowatts (kW)
• \( Voltage \) — Line-to-line voltage in volts (V)
• \( Power\ Factor \) — Ratio of real power to apparent power (0-1)
• \( Efficiency \) — 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 3-phase AC motor.

3. Importance of Current Calculation

Details: Accurate current calculation is essential for proper wire sizing, circuit breaker selection, overload protection, and energy efficiency analysis.

4. Using the Calculator

Tips: Enter motor power in kW, line voltage in V, typical power factor (0.8-0.95), and motor efficiency (usually 0.8-0.95). All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical power factor for motors?
A: Induction motors typically have 0.85-0.9 PF at full load, lower at partial loads.

Q2: How does voltage affect current?
A: Current is inversely proportional to voltage - higher voltage means lower current for same power.

Q3: Why include efficiency?
A: Efficiency accounts for power losses in the motor - actual current draw is higher than theoretical.

Q4: What about single-phase motors?
A: Single-phase motors use a different formula without the √3 factor.

Q5: How accurate is this calculation?
A: It provides theoretical full-load current. Actual current varies with load, temperature, and voltage fluctuations.