Both of your trips and the nonspecific location point to excessive current which looks more like overload. Can you turn the motor by hand? Did you check for mechanical issues? When it does run is your currentr at maximum?
Auto tune doesn’t always work. If there is a filter (reactor) in the output most drives fail to tune. It also doesn’t do well on deep bar or double cage rotors (high starting torque). The math won’t converge. .
Often you can bypass filters and get most of the tuning done that way. A trick is to bypass and do “full” auto tune. Then reconnect and do IR drop only since that should always work. You can also calculate most of the settings from the motor manufacturers data sheet or worst case use IEEE 112 procedure.
Finally if performance is acceptable or for testing just switch to V/Hz mode. This mode works “out of the box even without tuning. The only nice to have parameter is IR drop that you can measure with a multimeter.
Keep in mind what is happening. In V/Hz (scalar) mode the VFD generates voltages with NO feedback or minimal feedback in “compensated” modes. It adjusts the voltage up a few percent for IR drop but that’s it. It is “stupid”. That’s why this mode may lack tight speed control but nearly always works. In vector modes the drive is estimating speed and torque by reading the current and optionally an encoder. It needs to accurately model the motor which is where auto tuning comes in. Also vector mode can give you trouble if the motor gets excessively hot. If this happens the tuning is no longer accurate, particularly IR drop. It can be enough to affect performance of vector mode. If this happens you may have to use an encoder since there is much less “guessing” in that mode. RPM is known and the drive only has to distinguish torque vs flux and not very accurately.
