Mike: What controller on the DYNACNC setup? If it is one of our complete controllers (grey fiberglass box) with the red estop button on the front then I can help you. The power supply itself has an overload sensor and will shut down, BEFORE there can be damage to the drives or motors. If it's shutting down from a drive fault rather than a power overload it's doing to take some detective work. Some models we provided had a row of diagnostic LED's inside the controller. If it's one of our power supply/controller boxes then contact me direct or over on our Yahoo Support Forum.