IEEE 125-1988 pdf free.IEEE Recommended Practice for Preparation of Equipment Specifications for Speed-Governing of  Hydraulic Turbines Intended to Drive Electric Generators.
IEEE 125 governing system. The combination of devices and mechanisms that detects speed deviation and converts it into a change in servomotor position. It includes the speed sensing clcnicnts. the governor control actuator, the hydraulic pressure supply system. and the turbine control scrvomotor. The temis “goserno?’ and “governor equipment” arc commonly used in the industry to descnhe the governing system and will be used interchangeably with thc term ‘governing system” in this spccitication
spccd sensing elements. The spccd responsive elements that determine speed and influence the action of other elements of the governing system. Included are the means used to transmit a signal proportional to the speed of the turbine to the governor.
governor control actuator. The combination of devices and mechanisms that detects a speed error and develops a corresponding hydraulic control output to the turbine control servomotors. hut does not include the turbine control scrvomotors. Includes gate. blade, deflector, or needle control, or all equipment as appropriate.hydniulic pressure supply system. The pumps, means for driving them, pressure and sump tanks, valves and piping connecting the various parts of the governing system. and associated and accessory devices.
rlectric.hydraulic governor. A governor in which thc control signal is proportional to speed cmr and the stabileiing signals are developed electrically, summed by appropriate electrical networks, and arc then hydraulically amplified. Electrical signals may he derived by analog or digital means.
mechanical-hydraulic governor. A governor in which the control signal proportional to speed cmw and necessary stahiliting signals are developed mechanically, summed by a mechanical system, and arc then hydraulically amplified.
distributing sahe. The element of the govcrnor.contrnl actuator that controls the flow at hydraulic fluid to the turbine-control sersomolor(s).IEEE 125 pdf download.