Probable cause may be :-
1. Winding resistance unbalance.
2. Winding inductance unbalance.
3. Motor shaft play.
4. Motor vibration may increase.
5. Motor power cable burn somewhere/ carbonized.
May be other cause too.
1. First this is check the motor resistance and inductance by motor checker.
Procedure to check the motor Resistance:-
Disconnect all three motor phase connection from motor terminal , and take out the three lead from stud.
Then take reading of resistance of R- phase,Y- phase, B -phase by connecting checker lead to motor phase lead one by one.
Resistance should be balance.
Procedure to check the motor inductance:-
Disconnect all three motor phase connection from motor terminal , and take out the three lead from stud.
Then take reading of inductance of R- phase,Y- phase, B -phase by connecting checker lead to motor phase lead one by one.
Inductance should be balance.
2. In some cases i found if there is play in shaft then also motor trip in current unbalance. So if motor winding resistance and inductance is balance then check there also.
3. Check motor vibration also as per standard.
4. If motor power burn near socket, somewhere then also I found motor trip in unbalance.
So if motor trip in unbalance then above steps will help to find out the reason of motor trip
If any questions please let me know.
Regards.
