Measuring the transformer ratio from one external terminal to another can reveal a lot of information about the transformer. Transformers are subject to mechanical shock and vibration. Problems or errors occur as a result of poor design, assembly, handling, poor environments, overloading, or bad maintenance. Measuring the polarity and turn ratio of a transformer winding ensures that the connections are correct and there are no serious mismatches or opens.
This application note focuses on the use of transformer shift ratio measurements for diagnostics purposes. It does not replace the owner's manual for the actual instrument and does not describe the practical operation. Instead, this document describes the relevant standards for ratio measurements and how these principles influence practical testing