Abstract: A drive turbine having a steam pressure-increasing device connected thereto. Steam taken from a high pressure steam source is utilized as the driving fluid for the pressure-increasing device disposed between the drive turbine inlet and a lower pressure drive turbine steam supply source. The pressure-increasing device increases the pressure level from the steam supply to the drive turbine to maintain a predetermined level of pressure in the supply steam flow.

Abstract: A control system for an extraction type steam turbine driven by steam from a steam generator wherein it is desired to control the steam pressure in the steam generator, at a predetermined level, by varying the position of the steam inlet valve. Turbine speed may be controlled at a predetermined level by varying the position of an extraction control valve. The inlet valve and the extraction valve are independently operable except under a condition where the extraction valve is completely closed and the turbine speed continues to rise. In this instance, means are provided for positioning the inlet valve according to a speed control signal which dominates an inlet pressure control signal for lowering the inlet steam valve until normal conditions are restored.