Maintaining electro-hydraulic-control (EHC) systems for turbine generators using phosphate ester EHC fluid

The requirements for maintaining an electrohydraulic control system through proper care of the phosphate ester fluid are described. Phosphate ester fluids are used on EHC turbine generator controls for their fire resistant characteristics that reduce the risk of fires if a leak were to occur. Some of the key elements in maintaining the fluid are shown to be cleanliness by proper maintenance and use of the auxiliary filtering system, maintenance of moisture content below 0.10%, maintenance of the temperature of the fluid between 110°F and 115°F, maintenance of resistivity of the fluid above 5000 MΩ/cm, and maintenance of acid neutralization number below 0.20 (mg KOH/g), which is affected by all of the above. The effects of operating a system with contaminated fluid and the cleanup of a contaminated system are discussed