One side of the secondary of all CTs must be earthed. The earth connection should be made on the side of the secondary facing the protected object. The polarity of the CTs must be in accordance with the following diagram.
This manual covers Electrically Power Governor (EPG) models 512/524 and
1712/1724. Refer to the appropriate manual or contact Woodward for information
about other versions of the EPG.
Application
The EPG is used to control the speed of diesel, gas, and gasoline engines. It can
also control the speed of gas turbines. Installation of EPG actuators is simple
because they require neither mechanical drive nor hydraulic supply.
The EPG handles prime movers with mechanical loads and generator loads
equally well. Generator sets which will be paralleled, however, require additional
appropriate switch gear, current and potential transformers, and the Woodward
Generator Load Sensor.
An EPG is a three-component system, requiring a magnetic pickup, speed
control, and actuator.
A battery charger must be used to keep the battery charged. Maximum steady
state current consumption is 4 A for the 12-volt models (512/1712), and 3 A for
the 24-volt models (524/1724).
Part Number Selection
Use EPG Model 512/1712 for operation in 12-volt systems. Use Model 524/1724
for operation in 24-volt systems.
Additionally, speed controls are available for four ranges of magnetic pickup
frequencies, for diesel engines and gas turbines, or for gasoline and gas
engines. Actuators have a double-ended output shaft for either clockwise or
counterclockwise rotation to increase fuel.
Speed controls and actuators must be compatible. Use the Part Number
Selection Table below (Table 1-1) to choose compatible EPG speed controls and
actuators.
The optional Start Fuel Limit feature allows setting a maximum actuator position
during start-up. The maximum position remains in effect until the engine reaches
the selected idle or rated speed. The limit may be adjusted out of the way by
turning the adjustment potentiometer fully clockwise.
The Dual Dynamics feature allows tailoring a special set of responses for
unloaded and loaded operating conditions. This type of control is often needed
for gas engines and other systems with non-linear fuel systems. A switch is used
to change between slow and fast dynamics.
