1. What is Motor Current Rating?

The current rating of a motor is the amount of electrical current it draws when operating at full load. For a 15 kW motor, this depends on the supply voltage, power factor, and motor efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• 15 kW — Motor power rating (converted to 15,000 Watts)
• √3 — Factor for three-phase systems (≈1.732)
• Voltage — Line voltage in volts
• Power Factor — Typically 0.8-0.95 for motors
• Efficiency — Typically 0.85-0.95 for modern motors

Explanation: The formula converts kW to watts, then divides by the product of voltage, power factor, and efficiency to find current.

3. Importance of Current Calculation

Details: Knowing the current rating is essential for proper wire sizing, circuit breaker selection, and overload protection to ensure safe and efficient motor operation.

4. Using the Calculator

Tips: Enter the supply voltage in volts, power factor (typically 0.85), and motor efficiency (typically 0.9). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is power factor important?
A: Power factor represents the phase difference between voltage and current. Lower power factors mean more current is needed for the same real power.

Q2: What's a typical current for a 15 kW motor?
A: At 400V, 0.85 PF, and 0.9 efficiency: ~28A. At 230V: ~49A. Actual values depend on your specific parameters.

Q3: Is this for single-phase or three-phase?
A: This calculator is for three-phase motors. Single-phase would use a different formula without the √3 factor.

Q4: How does voltage affect current?
A: Current is inversely proportional to voltage. Higher voltage means lower current for the same power.

Q5: What if I don't know the efficiency?
A: For estimation, use 0.9 for modern motors. For precise calculations, consult motor specifications.