Diesel Generator and Alternator FAT Guide

By LANDTOP Technical Team

A factory acceptance test should verify the ordered equipment's identity, assembly, electrical safety, insulation, controls, protection functions, operating performance, load behavior, and documentation before shipment. An approved protocol must identify the tested configuration, responsibilities, instruments, conditions, acceptance criteria, recorded results, deviations, retesting, and shipment-release authority.

Freeze the FAT scope and pass criteria before testing.
Distinguish complete generator-set tests from alternator-only tests.
Retain traceable readings, calibration evidence, deviations, and approvals.
Treat remote witnessing as controlled evidence collection, not merely a video call.

Approve the protocol and documents

Confirm drawings, datasheets, nameplates, test sequence, rated conditions, witness points, acceptance criteria, instrument list, and required deliverables.

Inspect and test the equipment

Check assembly, wiring, earthing, insulation, controls, alarms, shutdowns, output, frequency, voltage, and agreed performance under the specified conditions.

Resolve deviations and release shipment

Record each nonconformity, approve corrective action, repeat affected tests, and obtain authorized acceptance before shipment.

Is a FAT the same as site acceptance testing?

No. FAT occurs before shipment at the factory; site testing verifies installation, interfaces, and performance under site conditions.

Does an alternator FAT prove the complete genset?

No. Alternator evidence does not verify the engine, cooling system, controller, starting system, enclosure, or integrated protections.

Can buyers witness FAT remotely?

Yes, if identity, instrument displays, test sequence, raw readings, deviations, and signed records remain independently reviewable.

Scope and quality verification

The contract should identify whether testing covers an alternator or an integrated diesel generator set. The International Organization for Standardization's ISO 8528-6 test-method standard addresses generating-set test methods. This supports agreeing the test method and declared performance class instead of using an undefined request to test the generator.

For rotating electrical-machine characteristics, the International Electrotechnical Commission's IEC 60034-1 rating and performance standard establishes relevant machine-rating and performance requirements. Buyers should state the applicable edition and contractual limits rather than assume every clause automatically applies.

Use documented FAT acceptance criteria and an agreed staged load test procedure. Load steps, duration, power factor, ambient conditions, stabilization rules, and recorded parameters must match the purchase specification.

Checks, instruments, and responsibilities

The supplier prepares equipment, procedures, competent personnel, instruments, and records. The buyer approves scope and dispositions; an independent witness observes without silently redefining contractual criteria. Use a complete FAT test checklist for visual, mechanical, electrical, safety, control, protection, and performance checks.

The US National Institute of Standards and Technology explains in its metrological traceability guidance that traceability requires a documented, unbroken calibration chain with stated uncertainties. Therefore, buyers should verify instrument identity, range, calibration status, and suitability—not merely the presence of a sticker.

Deviations, records, and witnessing

Every deviation should identify the requirement, observed result, disposition, corrective action, retest, and approval. The final package should include the approved procedure, configuration record, calibration evidence, raw readings, photographs where relevant, deviation log, signed release, and a consistent FAT report template.

On-site and remote witnesses should see the same evidence. For emergency-power projects governed by a specified code, verify local applicability separately; the US National Fire Protection Association's NFPA 110 standard page shows that emergency and standby systems have system-level requirements, so a factory test alone does not replace installation and site acceptance activities. Before authorizing shipment, procurement, engineering, and quality teams should jointly confirm that unresolved deviations are contractually acceptable.