摘要 |
PURPOSE:To improve the reliability of a control system by providing a tandem steam turbine with plural speed detectors and using signals from the speed detector for recording and indicating speed when an exclusive detector for controlling speed and load gets out of order. CONSTITUTION:A control system for a tandem steam turbine is provided with plural speed detector DP1-3 and ones for recording and indicating speed DP4, 5. Signals sent from the above detectors are inputted into a majority logic circuit ML, and the most reliable of signals sent from exclusive speed detectors for controlling speed and load is selected to be used. When one or more of the above signals are judged to be abnormal, the signals sent from the speed detectors for recording and indicating speed DP4, 5 are added to the above signals, and then the most reliable of these signals is selected. Consequently, the reliability of the control system can be improved. |