| 摘要 |
PURPOSE:To detect a trouble without malfunction by detecting as a trouble only when the output voltage values of at least one or two phases of three phases exhibits abnormality. CONSTITUTION:The voltages of the phases of a 3-phase AC exciter 1 are output by a transformer 6, fed through an arrester 10, a smoothing circuit 11 and an A/D converter 12, and input to a discriminator 7. In order not to operate a detector at the time of normal operation such as start or stop, a trouble signal is not oscillated when the signals transmitted from the phases are all '0' or '1' (i.e., stopping and normal operating states). However, only when at least one of these signals is '0', the detector judges that a trouble occurs in the exciter 1 to generate a trouble signal. |
