Recently we had a contractor update a piece of equipment that has 20 pay off shafts that employ PM motors to power push or pull the shafts to maintain tension and dancer position. Out of these 20 units that were updated, at least 5 drives went belly up when power was applied to the machine. (all drives run off the same source of 230V). 3 of them had shorted SCR bridges, one lost it's
15 volt power supply while the last one for some reason thinks when the drive is to go in the forward direction it detects an overload with no actual voltage being generated at the bridge for the A1 and A2 lines! also, Amp meter indicates that there really isn't any current being generated! So i can only assume something is wrong with the max current sense for the forward direction ?In any case, what is the chance of these drives being shipped in this condition ? this is the NEMA 240D regen 1/2 Hp 120/230 volt drives.
Personally, i think the guy may have had the voltage set wrong on the defective units?