{"id":2129,"date":"2026-07-29T09:00:00","date_gmt":"2026-07-29T01:00:00","guid":{"rendered":"https:\/\/lbajiele.com\/?p=2129"},"modified":"2026-07-21T11:38:51","modified_gmt":"2026-07-21T03:38:51","slug":"factory-acceptance-testing-power-transformers-importer-witness-checklist","status":"publish","type":"post","link":"https:\/\/lbajiele.com\/de\/blog\/factory-acceptance-testing-power-transformers-importer-witness-checklist\/","title":{"rendered":"Werksabnahmepr\u00fcfung f\u00fcr Leistungstransformatoren: Checkliste f\u00fcr die Teilnahme des Importeurs"},"content":{"rendered":"<div class=\"b2b-article\">\n<p style=\"margin:0 0 16px;line-height:1.7\"><strong>Transformer factory acceptance testing<\/strong> is the last moment problems are the factory&#8217;s to fix at the factory&#8217;s cost\u2014after shipment, every issue becomes a negotiation.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Importers who witness FAT with a structured checklist consistently receive better-documented units. This guide covers the tests to witness, the logistics, and the release criteria.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Write witness rights into the purchase contract; they are difficult to add later.<\/p>\n<figure style=\"margin:26px 0;text-align:center\"><img decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px\" alt=\"Factory acceptance testing overview for power transformer importers\" src=\"https:\/\/lbajiele.com\/wp-content\/uploads\/2026\/04\/Transformer_case2.webp\" \/><\/figure>\n<nav class=\"b2b-toc\" style=\"background:#f5f8fa;padding:16px 20px;border-radius:8px;margin:0 0 24px\">\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\">Contents<\/h2>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7\">\n<li style=\"margin:0 0 8px\"><a href=\"#part-1-what-fat-covers-and-why-witnessing-matters\">Part 1. What FAT covers and why witnessing matters<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-2-routine-tests-to-witness\">Part 2. Routine tests to witness<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-3-type-and-special-tests\">Part 3. Type and special tests<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-4-witness-logistics\">Part 4. Witness logistics<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-5-documentation-and-release\">Part 5. Documentation and release<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-6-product-recommendation-and-fit-boundary\">Part 6. Product recommendation and Fit Boundary<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#part-7-common-fat-mistakes\">Part 7. Common FAT mistakes<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#faq\">FAQ<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"#references\">References<\/a><\/li>\n<\/ul>\n<\/nav>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-1-what-fat-covers-and-why-witnessing-matters\">Part 1. What FAT covers and why witnessing matters<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Factory acceptance testing bundles the routine tests performed on every unit with any contracted type or special tests, executed before shipment release.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Witnessing\u2014on site or remote\u2014verifies the tests happen on your unit, with calibrated equipment, against the agreed acceptance criteria.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">For related context, see the <a href=\"https:\/\/lbajiele.com\/de\/blog\/2000kva-oil-immersed-power-specifications-rfq-guide\/\">2000KVA oil immersed specifications and RFQ guide<\/a>.<br \/>\nFor related context, see the <a href=\"https:\/\/lbajiele.com\/de\/blog\/800kva-oil-immersed-specifications-rfq-checklist\/\">800KVA oil immersed specifications and RFQ checklist<\/a>.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-2-routine-tests-to-witness\">Part 2. Routine tests to witness<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Six routine tests carry most of the acceptance weight.<\/p>\n<figure style=\"margin:26px 0;text-align:center\"><img decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px\" alt=\"Routine test witnessing for power transformers at the factory\" src=\"https:\/\/lbajiele.com\/wp-content\/uploads\/2026\/04\/Transformer_case1.webp\" \/><\/figure>\n<table style=\"width:100%;border-collapse:collapse\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Test<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">What it proves<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Widerstand der Wicklung<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Joint quality and conductor integrity<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Ratio and vector group check<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Nameplate ratings and connection correctness<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">No-load loss and current<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Core quality at rated excitation<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Load loss and impedance<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Guaranteed losses and short-circuit impedance at reference temperature<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Applied and induced voltage tests<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Insulation withstand between and within windings<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Isolationswiderstand<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Dryness and assembly quality<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"margin:0 0 16px;line-height:1.7\">IEC 60076-1 and IEEE C57.12.90 define the methods and tolerances; name the edition in the contract so acceptance criteria stay unambiguous.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-3-type-and-special-tests\">Part 3. Type and special tests<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Type tests\u2014temperature rise, lightning impulse, short-circuit withstand\u2014prove the design family rather than each unit.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Accept existing type test reports on identical designs where schedule matters; require witnessed repeats only when the design is new or the project demands it.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Special tests such as sound level measurement belong in the contract explicitly, with acceptance values.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-4-witness-logistics\">Part 4. Witness logistics<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Agree notice periods, hold points, and re-test rules before production starts\u2014chasing them during testing wastes leverage.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Remote witnessing works when the factory provides live instrument views and signed raw data; state the format in the contract.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">One competent witness carrying the test plan beats a delegation without it.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-5-documentation-and-release\">Part 5. Documentation and release<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\">Release shipment against a document set: signed test reports with raw data, nameplate photo, calibration references, and closure of any non-conformities.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Check report values against guaranteed figures\u2014losses and short-circuit impedance carry commercial tolerances that affect price adjustments.<\/p>\n<p style=\"margin:0 0 16px;line-height:1.7\">Document acceptance comes first; shipment release follows it, never the reverse.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-6-product-recommendation-and-fit-boundary\">Part 6. Product recommendation and Fit Boundary<\/h2>\n<p style=\"margin:0 0 16px;line-height:1.7\"><strong>Product recommendation:<\/strong> Test scope and acceptance criteria are series-level topics\u2014settle them during selection. Start at the <a href=\"https:\/\/lbajiele.com\/de\/transformer\/\">transformer product category<\/a>, then review the <a href=\"https:\/\/lbajiele.com\/de\/produkt\/s-m-oil-immersed-power-transformer\/\">S\u25a1-M oil-immersed power transformer series<\/a> und der <a href=\"https:\/\/lbajiele.com\/de\/produkt\/scb-resin-insulation-dry-transformer-series\/\">SC(B) resin insulated dry transformer series<\/a> against the approved specification.<\/p>\n<figure style=\"margin:26px 0;text-align:center\"><img decoding=\"async\" style=\"max-width:640px;width:100%;height:auto;display:block;margin:0 auto;border-radius:8px\" alt=\"Transformer series for factory acceptance test planning\" src=\"https:\/\/lbajiele.com\/wp-content\/uploads\/2026\/04\/S20-M-OIL-IMMERSED-POWER-TRANSFORMER-2.webp\" \/><\/figure>\n<table style=\"width:100%;border-collapse:collapse\">\n<thead>\n<tr>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Better fit<\/th>\n<th style=\"border:1px solid #d9e1e8;padding:9px 12px;background:#f5f8fa;text-align:left\">Poor fit without extra study<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Contracts naming tests, standards, and editions<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Assuming FAT is included without written scope<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Importers with witness rights in the purchase order<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Requesting witnessing after production ends<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Teams checking reports against guaranteed figures<\/td>\n<td style=\"border:1px solid #d9e1e8;padding:9px 12px\">Filing unread test reports at handover<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"margin:0 0 16px;line-height:1.7\">Submit the rated kVA and voltage combination, vector group and tap range, no-load and load losses, cooling method and enclosure, and short-circuit impedance target through <a href=\"https:\/\/lbajiele.com\/de\/contact-us\/\">Kontaktieren Sie uns<\/a> for model-specific confirmation.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"part-7-common-fat-mistakes\">Part 7. Common FAT mistakes<\/h2>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7\">\n<li style=\"margin:0 0 8px\">Signing contracts without witness rights or notice periods.<\/li>\n<li style=\"margin:0 0 8px\">Accepting summary sheets without raw measurement data.<\/li>\n<li style=\"margin:0 0 8px\">Ignoring the reference temperature when checking loss guarantees.<\/li>\n<li style=\"margin:0 0 8px\">Treating type test reports from a different design as equivalent evidence.<\/li>\n<li style=\"margin:0 0 8px\">Skipping calibration record checks on the test equipment.<\/li>\n<li style=\"margin:0 0 8px\">Releasing shipment before non-conformities are closed in writing.<\/li>\n<\/ul>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"faq\">FAQ<\/h2>\n<h3 style=\"margin:28px 0 12px\">What is factory acceptance testing for transformers?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">The routine, type, and special tests executed at the factory before shipment release, checked against contracted acceptance criteria.<\/p>\n<h3 style=\"margin:28px 0 12px\">Which routine tests should importers witness?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Ratio and vector group, winding resistance, no-load and load loss with impedance, applied and induced voltage, and insulation resistance.<\/p>\n<h3 style=\"margin:28px 0 12px\">What is the difference between routine and type tests?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Routine tests run on every unit; type tests prove the design family once\u2014temperature rise, impulse, and short-circuit withstand.<\/p>\n<h3 style=\"margin:28px 0 12px\">Can factory acceptance testing be witnessed remotely?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Yes\u2014with live instrument views, signed raw data, and a contract clause defining the remote format and hold points.<\/p>\n<h3 style=\"margin:28px 0 12px\">What documents follow a passed FAT?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Signed test reports with raw data, calibration references, nameplate records, and written closure of any non-conformities.<\/p>\n<h3 style=\"margin:28px 0 12px\">What happens if a test result misses its limit during FAT?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">The factory investigates, corrects, and re-tests under the agreed re-test rules; shipment release waits for closure.<\/p>\n<h3 style=\"margin:28px 0 12px\">How much notice should the factory give before FAT?<\/h3>\n<p style=\"margin:0 0 16px;line-height:1.7\">Contracts commonly set one to two weeks of notice; fix the period explicitly so travel and remote setup stay plannable.<\/p>\n<h2 style=\"margin:42px 0 14px;scroll-margin-top:96px\" id=\"references\">References<\/h2>\n<ul style=\"margin:0 0 18px 1.2em;line-height:1.7\">\n<li style=\"margin:0 0 8px\"><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/588\" rel=\"nofollow noopener\" target=\"_blank\">IEC 60076-1: Power transformers \u2014 General requirements<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"https:\/\/standards.ieee.org\/ieee\/C57.12.90\/5133\/\" rel=\"nofollow noopener\" target=\"_blank\">IEEE C57.12.90: Test code for liquid-immersed transformers<\/a><\/li>\n<li style=\"margin:0 0 8px\"><a href=\"https:\/\/standards.ieee.org\/ieee\/C57.12.00\/6788\/\" rel=\"nofollow noopener\" target=\"_blank\">IEEE C57.12.00: General requirements for liquid-immersed transformers<\/a><\/li>\n<\/ul>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Transformer factory acceptance testing is the last moment problems are the factory&#8217;s to fix at the factory&#8217;s cost\u2014after shipment, every issue becomes a negotiation. Importers who witness FAT with a structured checklist consistently receive better-documented units. This guide covers the tests to witness, the logistics, and the release criteria. Write witness rights into the purchase [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":1552,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[31],"tags":[],"class_list":["post-2129","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/posts\/2129","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/comments?post=2129"}],"version-history":[{"count":1,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/posts\/2129\/revisions"}],"predecessor-version":[{"id":2142,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/posts\/2129\/revisions\/2142"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/media\/1552"}],"wp:attachment":[{"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/media?parent=2129"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/categories?post=2129"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lbajiele.com\/de\/wp-json\/wp\/v2\/tags?post=2129"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}