| 摘要 |
PROBLEM TO BE SOLVED: To prevent shortening of life of a light-emitting element, which generates a return signal with an arc-ignition/extinction monitoring device, which monitors operation of a switching device, on-off controlled by an optical signal. SOLUTION: The light-emitting element for instruction signal generates an instruction signal, which controls the switching device, on-off controlled by the optical signal. The light-emitting element for return signal extinguishes light when the switching device is in a turn-on state, and generates the return signal by emitting light when the switching device is in a turn-off state. A failure detection means detects a failure by monitoring the return signal generated using the light-emitting element for return signal. The light of the light- emitting element for return signal is extinguished by an extinction control means, after the operation of the failure detection means is nullified by a failure detection control means when operation of an electric power converter is stopped for a certain time or more. |
