| 1. Define the duty rating | Confirm whether the required output is standby, prime, or continuous power. These ratings describe different operating conditions and are not interchangeable. | Rating definitions, nameplate data, and the proposed operating profile, including expected running hours and load pattern. | Compare offers at the same rating basis, voltage, frequency, and power factor. Do not compare a standby rating in one offer with a prime rating in another. |
| 2. Compare generator designs | Review open-frame, weather-protective, sound-attenuated, and containerized configurations. Consider installation space, ventilation, access, and environmental exposure. | General arrangement drawings, dimensions, airflow details, lifting points, access-door locations, and enclosure material or corrosion-protection details. | Check that the design fits the site and allows safe access for routine inspection and maintenance. |
| 3. Check engine and alternator matching | Assess whether the engine and alternator are properly sized for the required kW, kVA, voltage, frequency, starting loads, and site conditions. | Technical datasheets for both components, alternator temperature-rise information, and any stated derating for altitude or ambient temperature. | Ask the supplier to identify the complete set’s rated output under the actual site conditions, rather than relying only on component maximum ratings. |
| 4. Verify performance requirements | Compare voltage and frequency regulation, transient response, and the applicable performance class for the intended application. | Declared performance data and the specific ISO 8528 requirements or performance class referenced in the proposal, where applicable. | Match the performance requirements to the connected loads; sensitive equipment and large motor starts may need closer review. |
| 5. Specify customization clearly | Review options such as control-panel functions, automatic transfer interfaces, remote monitoring, cable entry, fuel-tank arrangement, and enclosure layout. | A written options list, interface description, electrical drawings, and a revision-controlled final configuration. | Separate included items from optional items, and confirm that customized parts remain accessible for service and replacement. |
| 6. Check fuel and emissions suitability | Confirm the proposed fuel system, fuel consumption data at stated loads, tank capacity, and emissions requirements for the destination and application. | Fuel-consumption curves or values with their load basis, emissions documentation where required, and fuel-system drawings. | Check applicable local regulations and installation rules. Emissions requirements depend on the destination, equipment category, and use case. |
| 7. Assess noise data properly | Compare sound-pressure figures only when the measurement conditions are stated, including distance, operating load, and test environment. | Noise-test report identifying the measurement method, microphone distance, load condition, and whether the reading is sound pressure or sound power. | A decibel figure without its measurement conditions is not a reliable basis for comparing generator sets. |
| 8. Review load-test procedures | Check whether the factory performs a documented test under load and whether the procedure matches the order and applicable specifications. | Test procedure and results showing the unit’s identification, rated values, test conditions, measured readings, and test date. | Load-bank tests commonly record several load steps, such as 25%, 50%, 75%, and 100%, when appropriate to the unit and agreed procedure. |
| 9. Verify test-record traceability | Confirm that records relate to the specific generator set being purchased, not merely to a similar model or a general sample unit. | Serial or order reference, instrument details or calibration status where relevant, recorded readings, acceptance criteria, and authorized sign-off. | Ask how any failed readings are documented, corrected, and retested. Agree in advance which records will be supplied before shipment. |
| 10. Evaluate quality and after-sales support | Review documented production controls, inspection stages, warranty scope, spare-parts availability, and technical support arrangements. | Quality-system documentation, inspection checklists, warranty terms, recommended spare-parts list, and service-response process. | Verify the scope and validity of any claimed certification, and make sure the warranty exclusions and service responsibilities are stated in writing. |