How to Choose the Right Diesel Generator for Your Facility
Investing in a diesel generator requires more than just knowing your facility's square footage. Selecting the correct industrial power equipment depends on understanding load requirements, application type, and site conditions to ensure reliable operation when you need it most.
1. Understand Your Power Rating Requirements
The most critical step in choosing a diesel generator is understanding how it will be used. Industrial generators are classified by their intended application. Choosing the wrong rating can lead to severe engine damage, voided warranties, or failure during an outage.
Standby Power
Designed for emergency backup during utility outages. These units are rated to run for a limited number of hours per year and should not be used as a primary power source.
Prime Power
Built to run continuously as the primary power source for variable loads. Ideal for remote industrial sites, mining operations, or locations without a stable grid connection.
Continuous Power
Engineered to provide a constant load (100% of the rating) for an unlimited number of hours annually. Commonly used in utility scale operations or base-load power plants.
2. Calculate Accurate Load Sizing
A common mistake is sizing a generator based solely on the running wattage of the facility. Heavy industrial equipment, such as HVAC systems, large motors, and compressors, require a massive surge of power to start up—often three to five times their normal running wattage.
To accurately size your generator, you must calculate both the steady-state running load and the maximum peak starting load. If the generator cannot handle the surge, it will trip the breaker or stall the engine.
Buyer Note: Avoid "Wet Stacking"
Do not oversize your diesel generator "just in case." Running a diesel engine with a load consistently below 30-40% of its rated capacity leads to unburned fuel and carbon buildup in the exhaust system, a condition known as wet stacking. This significantly reduces engine life and performance.
3. Voltage and Phase Configuration
Industrial facilities almost exclusively require three-phase power, whereas residential or light commercial buildings may only need single-phase power. Before purchasing, verify your facility's specific electrical requirements.
| Specification | Single-Phase Generators | Three-Phase Generators |
|---|---|---|
| Typical Voltage | 120/240V | 120/208V, 277/480V, 4160V |
| Primary Application | Residential, small offices, light tools | Industrial plants, heavy machinery, data centers |
| Power Delivery | Power peaks and dips during cycles | Constant, steady power delivery for heavy loads |
4. Final Pre-Purchase Verification Checklist
Before moving forward with procurement, review these essential facility requirements to ensure a seamless installation and operation:
- Total Load Profile: Confirm you have mapped out the starting (surge) kW and running kW of all critical equipment.
- Physical Footprint: Verify you have adequate concrete pad space, clearance for maintenance access, and proper ventilation.
- Enclosure Needs: Determine if you require a weather-proof enclosure for outdoor elements or a sound-attenuated enclosure to meet local noise ordinances.
- Fuel Storage: Ensure your integrated base tank or external fuel storage provides sufficient runtime for your required emergency parameters (e.g., 24, 48, or 72 hours).
- Transfer Switch Compatibility: Verify that the Automatic Transfer Switch (ATS) matches the generator's amperage and facility voltage.
Need Help Sizing Your Generator?
APASOF supports customers with expert generator sizing, application review, and equipment sourcing. Our team can help review your load profile, physical site constraints, and technical requirements before the next step.
Contact APASOF