Diesel generator sizes from 10 to 3,000 kVA
Use this generator-size hub to compare common ratings, convert kVA and kW, and plan new or used diesel generator requirements.
Find the right generator size.
Start with the electrical load and operating duty, then compare the generator rating, installation and support as one system.
How generator sizes are expressed
Generator sets are normally advertised in kilovolt-amperes (kVA), while much connected equipment is described in kilowatts (kW) or amps. kVA represents apparent power and kW represents real power. At a power factor of 0.8, 100 kVA is approximately 80 kW; at unity power factor, 100 kVA would equal 100 kW. Use the power factor and voltage that apply to the actual installation.
For three-phase current, the guide calculation is amps = kVA × 1,000 ÷ (√3 × line voltage). This makes 100 kVA approximately 144 A at 400 V three phase. It does not select cables or protective devices: the final design must use the chosen generator’s data, installation method, fault level and applicable electrical standards.
Why connected load is not enough
A generator must support both steady running demand and transient events. Motors, pumps, compressors, lifts, transformers and UPS systems can impose high starting current or rapid load steps. A site with 120 kW of connected equipment may need a different solution depending on what starts together, the starting method, acceptable voltage dip and whether non-essential loads can be delayed.
Prime and standby ratings must also be separated. Emergency standby power covers operation during a normal source failure under the manufacturer’s rating definition. Prime power is used for longer variable-load duty. The same physical set may display different kVA values for those duties.
New, used, silent and open generators
New generators can be configured around the project. Used sets can offer attractive value and availability when their condition and specification align with the load. Acoustic or “silent” canopies reduce noise and provide weather protection, while open sets are intended for a suitable plant room or a separately engineered enclosure. Neither description replaces a site noise assessment or ventilation design.
FW Power supplies generator sets and supports installation, commissioning, servicing, load bank testing and project planning. Current stock is shown dynamically on the priority size pages; if there is no close catalogue match, the team can discuss sourcing or a new specification.
All commonly requested ratings
Linked ratings have a full technical landing page. Other values are included for comparison and can be discussed with the team without creating a thin or repetitive page.