Transformer Nameplate Decoder — Every Parameter Explained

Transformer nameplates pack a huge amount of information into a small metal plate, and misreading any parameter can lead to serious design errors or equipment damage. This A4 portrait poster presents a full-size annotated transformer nameplate diagram with callout lines pointing to every field: rated power (kVA/MVA), primary and secondary voltages, impedance voltage (Uk%), vector group designation (Dyn11, YNd1, etc.), cooling class (ONAN, ONAF, OFAF), insulation class, temperature rise limits, tap changer range, rated frequency, and serial/manufacturing data. Each callout includes the relevant IEC 60076 clause reference and a plain-English explanation of what the parameter means in practice — for example, why a 6% impedance voltage means your fault level will be approximately 16.7 times the rated current. A dedicated panel on the right side provides a vector group reference table showing the 12 most common configurations with their phase displacement angles, typical applications, and parallel operation compatibility rules. The bottom section covers nameplate markings you need for protection coordination: rated current, short-circuit withstand current (kA for 2 seconds), and the relationship between impedance voltage and prospective fault current. Essential for substation engineers, protection engineers, and anyone commissioning or specifying distribution transformers.