Factory Witness Tests - Power Transformer - What Tests? - Eng-Tips

I have not done FWT of a transformer but I would ask the mfr to provide their standard FWT procedures and offering and would review it. That will be the basis of the testing agenda.

Anything requiring an extensive test set up may not get accomplished in a day. I have yet to see any mfr being ready with the test setup before we arrive on the floor! Any special test requires advance notice.

Assuming load setup is there and only speaking for electrical:
I would go with more or less, your list starting with dielectric, impedance, Voltage regulation and losses. If oil filled, is there a way to check integrity of sealing for leakage(like a pressure test?).

Review their routine test reports?

I would also be interested in verifying the accessories to be present as specified that are easier to get fixed at the factory than on the site.


Rafiq Bulsara
Some tests will also be done in the field. These could be skipped in the factory witnessing because the field test will serve as a check. If the factory skips or bungles the turns ratio test, for instance, it will show up in the field. You don't want to find out that the turns ratio is wrong after delivery, but neither does the factory, so they aren't likely to screw that one up.

Frankly, unless you are concerned that the transformer manufacturer might not even do the tests without your being there to witness them, there isn't a whole lot of value in witnessing the tests. The tests are automated and computerized anyway, so you don't actually see anything but computer printouts. It's not like someone is reading values from an analog meter and writing them down so you can check on them.