“Choosing the wrong generator size can lead to expensive downtime or engine damage. Our engineering team at Elitech Power has summarized this technical guide to help you size your power plant like a pro.”
1. Understand Your Load Type: Starting vs. Running
Not all equipment consumes power equally. To avoid “Wet Stacking” or voltage drops, you must distinguish between:
- Resistive Loads: (Lighting, Heaters) Power consumption is constant.
- Inductive Loads: (Motors, Pumps, Compressors) These require a Starting Surge that can be 3 to 5 times their running wattage.
2. The kVA to kW Formula (Phase Matters)
In the industrial generator world, the relationship between kVA (Apparent Power) and kW (Actual Power) is defined by the Power Factor (PF). This factor changes depending on your phase system:
kW = kVA × 0.8
Typical for Industrial & Commercial sites.
kW = kVA × 1.0
Typical for Residential & Small tools.
3. The 20% Safety Rule
At Elitech Power, we always recommend sizing your generator at 20-25% above your peak calculated load. This “Safety Margin” prevents the engine from running at 100% capacity constantly, significantly extending the machine’s lifespan and protecting your warranty.
4. Warning: Amperage Differences
Expert Notice on Amperage (Amps):
For the same power output (kW), a Single Phase generator produces significantly higher current than a 3-phase unit (approximately 1.73 times more).
When purchasing a single-phase unit, you must ensure your cables, transfer switches (ATS), and circuit breakers are rated for this increased amperage to prevent overheating or fire hazards.
3-Phase: kW = kVA × 0.8 | Single Phase: kW = kVA × 1.0
Need a Precise Power Calculation?
Use our tool above to calculate kVA based on your phase and load type, or contact our engineers for a custom proposal.
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