| 摘要 |
PURPOSE:To enhance the reliability of a thyristor converter by instantaneously producing a protecting firing gate signal when irregular firings of the thyristor is expected due to the abnormal range of the output signal of a gate signal generator, causing a dangerous state to be arrived at. CONSTITUTION:A current of a light emitting element of a light emitting element current forming main circuit is detected by a signal detector 19. A signal discriminator 18 inputs the output of the current detector 19 and discriminates the peak value of the current and the malfunction of the signal amplitude. The output of the discriminator 18 is inputted to a gate control circuit 17', is supplied together with the output of the ordinary gate signal generating gate control circuit 17 to a switching element 16, thereby driving the element 16. |
