Factory Acceptance Tests for Cast-Resin Dry-Type Transformers: Setting Pass or Fail Checks
A buyer's guide to defining practical pass or fail checks for factory acceptance testing of cast-resin, oil-free dry-type distribution transformers, with questions to put in the RFQ and acceptance test.
Before signing off on a cast-resin dry-type distribution transformer, decide which factory acceptance test results will be treated as pass or fail, and write those thresholds into the purchase order rather than leaving them to the supplier's standard report. This decision shapes the RFQ, the witnessed test, and the acceptance record.
Start by asking which routine tests the supplier will perform on the offered unit and which results are recorded. For a cast-resin, oil-free design, buyers commonly want to see insulation resistance, winding resistance, ratio and polarity checks, and a applied-voltage or induced-voltage test, but confirm what the supplier actually offers rather than assuming a scope. Ask whether partial discharge measurement is included and how results are reported.
Define acceptance criteria in advance: what deviation from design ratio is acceptable, what insulation resistance value triggers rejection, and whether any partial discharge reading is a fail. Request the test procedure and a sample report with the quotation so the format can be reviewed before the witness test.
Before requesting a quote, confirm with the supplier which tests are routine versus optional, who witnesses them, what pass or fail limits apply, and whether the final report will state measured values against those limits.