In modern high power industrial processes, multipulse cycloconverters are fundamental to feed synchronous motors. Given the importance of these critical processes, especially for mining industry, the reliability of the high power drive is critical. Having a fault-tolerant cycloconverter is quite valuable and it will reduce the economic losses caused by long repair times of the converter. Currently it is difficult and in some cases almost impossible to determine which of the 72 SCRs experiences an over-current or those which do not trigger properly causing a malfunction. In this paper, we present a new fault detection method applied to a 12-pulse cycloconverter in way to develop a converter with the remarkable fault-tolerance capability.