What must stay online?
List the normal operating loads and expected simultaneous demand instead of adding every nameplate together.
MFG POWER · BUYER DECISION GUIDE
GENERATOR BUYING GUIDE
Define the duty, load, site condition, specification basis and acceptance criteria before asking suppliers to quote.
The first generator decision is not the brand or price. It is whether every supplier is quoting against the same requirement.
01 / DEFINE THE REQUIREMENT
DO NOT START WITH “I NEED A 100 kVA GENERATOR.”
The same headline rating can lead to very different machines, costs and operating results.
ApplicationBackup, prime, rental, construction, telecom, remote site, industrial process
LoadRunning load, starting current, motor load, nonlinear load, future expansion
DutyStandby, prime, continuous, hours per day, annual runtime
SiteAmbient temperature, altitude, dust, rain, noise, ventilation
ElectricalVoltage, frequency, phase, neutral, ATS / synchronizing, outlet or breaker arrangement
AcceptanceLoad test, temperature, noise, documents, packaging, spare parts, warranty path
02 / COMPARE LIKE FOR LIKE
SAME RATING. DIFFERENT MACHINE.
A quotation should be compared by component basis and operating condition, not by kVA alone.
EngineBrand/model, origin, rating basis, displacement, governing, emissions
AlternatorBrand/model, winding material, insulation class, temperature rise, AVR
ControllerBrand, protections, communication, ATS / AMF / synchronizing requirements
CoolingStandard ambient basis versus 50°C or project-specific requirement
Fuel systemTank capacity, autonomy, filtration, external tank connection
Canopy / enclosureMaterial, corrosion protection, acoustic basis, access and serviceability
03 / SIZE FROM THE LOAD
THE LOAD PROFILE MATTERS MORE THAN THE NAMEPLATE NUMBER.
What starts first?
Motors, compressors and pumps can create a starting requirement that is much higher than the running load.
What type of load is it?
UPS, VFD, rectifier and other nonlinear loads can change voltage regulation, harmonics and alternator sizing.
What changes later?
Allow for realistic future expansion without oversizing the generator so heavily that low-load operation becomes the new problem.
Buying rule: size from the real load profile, then verify the generator rating basis and transient behavior.
04 / DUTY CLASSIFICATION
PRIME AND STANDBY ARE NOT JUST LABELS.
Duty affects how the generator is expected to operate, how it should be sized and how supplier claims should be interpreted.
Read Prime vs Standby Power →STANDBYEmergency backup when normal power fails.
PRIMEVariable-load operation where the generator is a regular power source.
CONTINUOUS / BASE LOADStable-duty operation that needs a different rating and thermal basis.
05 / SITE CONDITIONS
THE SITE CAN DERATE THE MACHINE.
High temperature, altitude, dust, restricted ventilation and acoustic requirements can change the generator package that should be quoted.
50°C ambientCheck radiator basis, airflow, alternator temperature rise and engine derating.
AltitudeEngine output and cooling can fall as elevation rises.
Dust / sandFiltration, enclosure sealing and maintenance access become more important.
Noise limitRequire a stated test condition and measurement distance.
Rain / outdoorCheck enclosure, drainage, corrosion protection and ingress requirements.
06 / CONFIGURATION CONTROL
THE AGREED COMPONENT BASIS MUST SURVIVE PRODUCTION.
A quotation is not a control system. Critical components should be identifiable and verifiable.
EngineModel / rating / key options
AlternatorModel / copper winding / AVR / insulation
ControllerBrand / model / communication
BreakerBrand / rating / poles
Battery & chargerCapacity / charging arrangement
RadiatorAmbient design basis
Fuel tankCapacity / autonomy
CanopySteel / coating / access / acoustic basis
07 / VERIFY BEFORE RELEASE
INSPECTION SHOULD FOLLOW THE PRODUCTION STAGE.
PREConfirm supplier, specification and critical component basis before production.
MIDCheck whether the actual build still matches the agreed configuration.
FINALVerify function, assembly, documentation, packaging and visible defects.
FAT / LOAD TESTConfirm output and acceptance evidence before shipment release.
08 / COMMON BUYING MISTAKES
WHERE GENERATOR COMPARISONS GO WRONG.
01Comparing only kVA and price
The component and rating basis may be completely different.
02Ignoring starting load
The generator may run the load but fail when motors start.
03Accepting an ambient rating without checking site temperature
Cooling and output may not match hot-climate operation.
04Leaving component brands undefined
Substitution becomes easy once production starts.
05Treating final inspection as the only QC step
Some deviations are expensive or impossible to correct at the end.
06Assuming a warranty statement equals support
Parts, labor, response and claim process need to be defined.
MFG BUYER VIEW
CONTROL THE BASIS BEFORE YOU CONTROL THE PRICE.
For international buyers, the most expensive generator is not always the one with the highest quotation. It is often the machine that looked equivalent on paper but was built to a different duty, component or test basis.
MFG POWER approaches the buying decision from the buyer side: define the requirement, compare like-for-like, verify the build and release against evidence.
HAVE A GENERATOR REQUIREMENT OR QUOTATION?
CHECK THE BASIS BEFORE YOU COMMIT.
Send the requirement, supplier quotation or specification. MFG POWER can help identify comparison gaps, unclear assumptions and verification points before the order moves forward.
Review my requirement