| 摘要 |
PURPOSE:To avoid non-control state by providing a simulation feedback circuit for producing signal similar to valve opening signal in steam turbine controller for detecting steam valve opening and performing feedback control and exchanging upon fault of valve opening detector. CONSTITUTION:In a steam turbine controller 30, valve opening setting signal n1 produced from valve opening command signal (l) through function generator 32a is compared with signal q1 from steam valve position detector 37 in a comparator 33a to produce differential signal P1. A simulation feedback circuit 43a constituted with an adder 45a for adding other steam valve position detecting signal q2 and signal from bias circuit 44a is provided in said circuit. Upon fault of detector 37a, selective exchange circuit 42a comprising comparator 50a which will produce output when difference between signal n1 and q1 exceeds over predetermined level and quick change detector 51a will function to open contact 40a while to close contact 46a and to continue operation by means of simulated feedback signal. |
