1. What is a 3 Phase Motor Current Calculator?

Definition: This calculator determines the current drawn by a three-phase electric motor based on its power rating, operating voltage, and power factor.

Purpose: Helps electricians and engineers properly size electrical components and verify motor load requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I \) — Current (amps)
• \( P_{kW} \) — Motor power (kilowatts)
• \( V \) — Voltage (volts)
• \( PF \) — Power factor (0-1)

Explanation: Converts kW to watts (×1000), divides by the product of voltage, power factor, and √3 (1.732) for three-phase systems.

3. Importance of Current Calculation

Details: Accurate current calculation ensures proper wire sizing, circuit breaker selection, and prevents electrical system overloads.

4. Using the Calculator

Tips: Enter motor power in kW, operating voltage (default 480V), and power factor (default 0.85). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor (0-1) represents efficiency of power usage, with 1 being ideal. Motors typically have 0.8-0.9 PF.

Q2: Why √3 in the formula?
A: The square root of 3 (≈1.732) accounts for the phase difference in three-phase systems.

Q3: What voltage should I use?
A: Common three-phase voltages are 208V, 240V, 480V, or 600V - check motor nameplate.

Q4: How do I find motor power?
A: Check motor nameplate rating in kW or HP (1 HP ≈ 0.746 kW).

Q5: Does this include startup current?
A: No, this calculates running current only. Startup current can be 4-8 times higher.