Hi,
The motor is brand new - literally 12-14 operating hours old. We had this problem with the old motor fitted - and that had only a few running hours on the clock as the machine had not been run due to it's many mechanical and stepper problems. The old motor had been checked as OK by a motor rewinding company and it had new brushes fitted. When we had the problem, we fitted a new motor, but that had the same problem - changing the driver board and partially isolating the E-Stop seemed to cure the problem for some 12 operating hours, then it started happening all over again - there is no arcing from the motor and it runs just fine - until the "popping" of the trip.
Regards,
GeoffB