How to convert 2 phase power supply to 3 phase power supply using a Transformer (like Scott transformer)?
As far as I know the Scott-T transformer converts 2-phase to 3-phase. Your sketch shows that you only have one phase as input.



Figure 1. The Scott-T when used as a 2-phase to 3-phase converter requires two input phases at 90° to each other. Image source: Wikimedia Commons.

There is more on the subject in the linked article.





Figure 2. With your single-phase connection and rated ratios you could expect voltage readings as shown.

These are not too dissimilar to what you measured.



Note that when you have only two-wires on an AC supply that you have only a single phase supply - even if those two wires come off two of the phases on a three-phase supply. This should be clear if you consider that the voltage waveform between the two terminals is a single sinewave. For a poly-phase supply you need to have > 1 sinewave with a phase difference between them.

If you lose one phase on a 3-phase motor the motor the motor (usually) will not start as there is no rotational field. The motor in this condition is "single phase" even though it is connected to two phases of the supply.