I'm working in elevator world, i'm now in a strange situation.
The 3 Phase synchronous motor is connected by drive then main controller and a distribution board.
The faulty earth leakage circuit breaker keeps tripping when the motor just start to rotate.
I disconnected the UVW wires that connect the VFD to the motor, and the break was released and the earth leakage didn't trip.
The problem is that after checking the coils of the motor (UVW) by the continuity test between them and the motor chassis, there was no contact between them.
What is the possible diagnosis for this situation?