1. What is 3 Phase Motor Current Calculation?

The 3-phase motor current calculation determines the current drawn by an induction motor based on its power rating, supply voltage, power factor, and efficiency. This is essential for proper circuit design 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 as a decimal (0-1)

Explanation: The formula converts kW to watts (×1000), accounts for 3-phase power (√3), and adjusts for power factor and motor efficiency.

3. Importance of Current Calculation

Details: Accurate current calculation is crucial for selecting proper wire sizes, circuit breakers, overload protection, and ensuring safe operation of motor circuits.

4. Using the Calculator

Tips: Enter motor power in kW, line voltage in volts, typical power factor (0.8-0.95 for motors), and efficiency (usually 0.85-0.95). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical power factor for motors?
A: Induction motors typically have power factors between 0.80-0.95 at full load, lower at lighter loads.

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

Q3: Why include efficiency in the calculation?
A: Efficiency accounts for power losses in the motor, giving the actual current drawn from the supply.

Q4: What's the difference between line and phase current?
A: In delta connection, line current = √3 × phase current. In star connection, line current = phase current.

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