Choosing the right generator size is one of the most important decisions for any business. A generator that is too small may fail under load, while an oversized generator leads to unnecessary fuel consumption and higher costs.
This guide will help you determine the correct generator size based on your power requirements and application.
Correct generator sizing ensures reliable performance, fuel efficiency, and long-term cost savings. An incorrect selection can lead to power failures, equipment damage, and increased operating costs.
Before selecting a generator, you need to calculate your total power requirement. This is usually measured in kilowatts (kW).
List all equipment that will run on the generator and calculate their total power consumption.
Generators are rated in kVA, while most equipment is rated in kW. To convert kW to kVA, use the following formula:
kVA = kW / 0.8
The value 0.8 represents the standard power factor for most industrial applications.
Identify all equipment and sum their power usage.
Example:
Machinery: 300 kW
Lighting: 50 kW
Other equipment: 50 kW
Total Load = 400 kW
Using the formula:
400 / 0.8 = 500 kVA
Add 15–25% extra capacity for future expansion and startup loads.
Recommended generator size: 600 kVA
Typically require 100–500 kVA generators depending on equipment.
Industrial facilities usually require 500–2000 kVA generators.
Require reliable backup power, typically between 500–1500 kVA.
Offices and malls typically use 250–1000 kVA generators.
Choosing a generator based only on kW without conversion
Ignoring starting currents of motors
Not considering future expansion
Selecting a generator too small to reduce cost
Choosing the correct generator size is essential for reliable operation and cost efficiency. By calculating your total load, converting to kVA, and adding a safety margin, you can select the most suitable generator for your business.
Proper sizing not only ensures uninterrupted power but also optimizes fuel consumption and operational costs.
Explore our diesel generator solutions:
500 kVA Diesel Generator
1000 kVA Diesel Generator
Perkins Powered Generators
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