| 摘要 |
PURPOSE:To improve the reliability of a control device by tripling the control circuit of a turbine and also adding a self diagnostic function. CONSTITUTION:Three speed detectors are fitted to a turbine shaft and individual speed signals F1-F3 are converted to voltages V1-V3 by F/V converters 41- 43. The voltages V1-V3 are fed in twos into low value selection circuits 44-46, the outputs V4-V6 are fed into a high value selection circuit 47 for comparison with the preset signal VS of a preset circuit 48, and after calculation in a control circuit 50 a speed control signal Vepsilon is obtained. In addition, the voltages V1-V3 are fed to a high value selection circuit 49 and a control circuit 51 as a backup. Accordingly, even if any of the speed detection signals fails at the low value side or high value side, a normal control signal can be obtained. |
