Contributions concerning the oscilloscopic method, for checking the clock-hour figure of the vector group of a three phase, 50 VA electric transformer

The wiring diagrams, the vector groups and the clock hour figures of the vector group, are interesting aspects for designing, manufacturing and operating of, especially the power transformers. The achievement of a device for identifying the clock-hour figure for the three-phase transformer, built on the principles of oscilloscopic method and compensation method, represent the authors' contributions. The proposed solution leads to a major simplification of the oscilloscopic method, which, even if it bears the name used in the literature, does not use an oscilloscope, device considered expensive and complicated. This new approach leads to a higher precision of measurements, limiting the risk of errors, which can occur in case of small phase displacements. Index Terms--Electrical engineering, oscilloscopes, transformers, voltage measurement.