1. What is Full Load Current?

Full Load Current is the current drawn by an electric motor when operating at its rated power (in this case 75kW) and full load. It's a critical parameter for selecting proper wire size, circuit breakers, and overload protection devices.

2. How Does the Calculator Work?

The calculator uses the standard three-phase motor current formula:

Where:

• \( I \) — Full load current (Amps)
• \( P \) — Motor power rating (75,000 Watts for 75kW motor)
• \( V \) — Line voltage (Volts)
• \( PF \) — Power factor (0-1)
• \( \eta \) — Motor efficiency (0-1)

Explanation: The formula accounts for the three-phase power relationship and the motor's power factor and efficiency.

3. Importance of Full Load Current

Details: Knowing the full load current is essential for proper electrical system design, including conductor sizing, protection device selection, and voltage drop calculations.

4. Using the Calculator

Tips: Enter the motor's rated voltage, typical power factor (usually 0.8-0.9 for motors), and efficiency (usually 0.9-0.96 for modern motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is power factor important in this calculation?
A: Power factor represents the phase difference between voltage and current. Lower PF means the motor draws more current for the same real power.

Q2: What's a typical efficiency for 75kW motors?
A: Modern 75kW motors typically have 94-96% efficiency at full load, but this varies by motor design and load.

Q3: How does voltage affect the current?
A: Current is inversely proportional to voltage - higher voltage systems require less current for the same power.

Q4: Is this calculation valid for single-phase motors?
A: No, this is specifically for three-phase motors. Single-phase motors use a different formula.

Q5: Should I add a safety factor to the calculated current?
A: For protection devices, it's common to use 125% of full load current as a starting point per electrical codes.