Although the nameplate of the motor at the top states 400v @ 76Hz, for some reason, from your findings, that V/Hz ratio does not appear to be working. At the bottom of the nameplate, it states 400V @ 103Hz. Have you tried that V/Hz ratio? This motor should be connected delta and more than likely...
appears that your resistance is wrong. I would expect the cold resistance to be around 5.48 ohms and the hot resistance to be around 7.67 ohms. if the rpm is correct, one would assume you have the turns correct. possibly the original coils have two different wire sizes at the beginning and end...
