Normally the plate current of a motor is FLA (full load amps) so at no load it should be considerably less, make sure you test the currrent at 50hz and test each phase for balance.
The winding resistance will not really tell you anything, as you would not detect a shorted turn.
Often motors that are not inverter rated fail because some older motors do not have the resistance to switching spikes, due to insulation quality etc.
Does it trip on over-voltage or overcurrent?
Because if it does not have good internal braking quality, then if you have too short a decel, it causes over voltage (regenerative).
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.