HYDRAULIC GOVERNORS As droop is reduced toward zero the unit becomes able to change load without changing speed. As a general rule, units running alone should be set on zero droop, interconnected units should be run at the lowest droop setting that will give satisfactory load division. A.C, generating units tied in with other units should have droop set sufficiently high (30 to 50 on the dial) to prevent interchange of load between units. If one unit in the plant, or system, has enough capacity, its governor may be set on zero droop and it will regulate the frequency of the entire system. This unit will take all the load changes within the limits of its capacity and will control frequency if its capacity is not exceeded, The system frequency is adjusted by operating the synchronizer of the governor having zero droop. The distribution of load between units is accomplished by operating the synchronizers of the governors having speed droop. THE LOAD LIMIT control hydraulically limits the load that can be put on the engine by restricting the angular terminal shaft rotation of the governor, and consequently, the quantity of fuel supplied to the engine. The control may also be used for shutting down the engine by turning it to zero. CAUTION: DO NOT MANUALLY FORCE ENGINE LINKAGE TO INCREASE FUEL WITHOUT FIRST TURNING LOAD LIMIT KNOB TO 10. INSTALLATION When the governor is installed on the engine, particular care should be exercised to see that it is mounted squarely and that the drive connection to the engine is aligned properly. A gasket should 3-17