1. What is 3-Phase Motor Current?

The 3-phase motor current is the amount of electrical current drawn by a three-phase motor when operating under specific conditions of power, voltage, power factor, and efficiency.

2. How Does the Calculator Work?

The calculator uses the 3-phase motor current equation:

Where:

• \( I \) — Current in Amperes (A)
• \( P \) — Power in Watts (W)
• \( V \) — Line voltage in Volts (V)
• \( PF \) — Power factor (unitless, 0-1)
• \( eff \) — Motor efficiency (unitless, 0-1)

Explanation: The equation calculates the current drawn by a balanced three-phase motor accounting for its power factor and efficiency.

3. Importance of Current Calculation

Details: Accurate current calculation is crucial for proper sizing of circuit breakers, wires, and other electrical components to ensure safe and efficient motor operation.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work.

Q2: What's typical motor efficiency?
A: Standard motors typically have 85-95% efficiency, with higher efficiency motors reaching 95% or more.

Q3: Why use √3 in the formula?
A: The √3 factor accounts for the phase difference in three-phase systems (120° between phases).

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

Q5: How does voltage affect current?
A: Higher voltage reduces current for the same power, which is why high-power motors often use higher voltages.