Very glad to hear that you were able to find a convincing fault, - there is a general assumption that all faults to earth are a dead short from one line or another to ground. In his case presumably the fault was from part way along the windings to the case, so not taking a high current compared to the starting inrush, as would be needed to operate the instant protection, but it still adding enough extra current so the overload trip fires after the short period that is normally allowed for the thing to get up to speed.
Very glad to hear that you were able to find a convincing fault, - there is a general assumption that all faults to earth are a dead short from one line or another to ground. In his case presumably the fault was from part way along the windings to the case, so not taking a high current compared to the starting inrush, as would be needed to operate the instant protection, but it still adding enough extra current so the overload trip fires after the short period that is normally allowed for the thing to get up to speed.
