1. What is Generator Size Calculation?

Generator size calculation determines the appropriate capacity (in kVA) of a generator needed to power electrical equipment based on total wattage and power factor.

2. How Does the Calculator Work?

The calculator uses the generator size formula:

Where:

• Total Watts — Sum of all electrical loads in watts
• Power Factor — Ratio of real power to apparent power (typically 0.8 for most applications)

Explanation: The formula converts real power (watts) to apparent power (kVA) accounting for the efficiency of power delivery.

3. Importance of Proper Generator Sizing

Details: Correct generator sizing ensures reliable power supply, prevents overload, improves fuel efficiency, and extends equipment life.

4. Using the Calculator

Tips: Enter total connected load in watts and the power factor (default is 0.8). All values must be positive (watts > 0, 0 < power factor ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical power factor value?
A: Most generators operate at 0.8 power factor. Industrial equipment might have different power factors (0.7-0.95).

Q2: Should I add a safety margin?
A: Yes, it's recommended to add 20-25% to the calculated size for start-up surges and future expansion.

Q3: How do I calculate total watts?
A: Sum the wattage of all devices to be powered simultaneously, or use nameplate ratings of equipment.

Q4: What about motor starting currents?
A: Motors require 3-5 times their running current during startup. Special calculations are needed for motor loads.

Q5: Can this be used for three-phase systems?
A: This calculates single-phase size. For three-phase, additional calculations are needed for phase balancing.