No problem in time-varying slow ① Power voltage, there is no malfunction, it does not perform a non-safe operation. After returning to ② rated voltage, it is ready for use, no problem.
(1) Power supply voltage loose change when the malfunction, without no unsafe actions so no problem. (2) To rated voltage after his return, that can be used, with no problems.
(1), in 電源電圧緩変時, there isn't malfunction, and there is no problem in not working that is non-safe. (2) Is in an available condition after return to the rating voltage, and there is no problem.