1. What is a Generator Sizing Calculator?

Definition: This calculator estimates the required generator size in kilowatts based on the total electrical load and a safety factor.

Purpose: It helps homeowners, businesses, and contractors determine the appropriate generator capacity for their power needs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Required generator size (kilowatts)
• \( P_{load} \) — Total electrical load (watts)
• \( SF \) — Safety factor (typically 1.2-1.5)

Explanation: The total load in watts is converted to kilowatts (divided by 1000) then multiplied by a safety factor to account for startup surges and future expansion.

3. Importance of Proper Generator Sizing

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

4. Using the Calculator

Tips:

• Sum the wattage of all devices to be powered simultaneously
• Use higher safety factors (1.3-1.5) for motor loads or future expansion
• Consider both running and starting watts for motors

5. Frequently Asked Questions (FAQ)

Q1: Why is a safety factor needed?
A: It accounts for startup surges (especially with motors), voltage drops, and potential future power needs.

Q2: What's a typical safety factor?
A: Residential: 1.2-1.3, Commercial: 1.3-1.5, Industrial: 1.5 or higher depending on motor loads.

Q3: How do I find the total load?
A: Sum the wattage of all devices to be powered simultaneously. Check appliance labels or manuals.

Q4: Should I consider starting watts?
A: Yes, especially for motors (AC units, refrigerators, pumps) which require 3-7× their running watts during startup.

Q5: What if I have three-phase equipment?
A: Use our Three-Phase Generator Calculator for more complex three-phase power requirements.