Woodward 723PLUS Technical Manual page 41

Manual 26482
Load Sharing (Torque or Actuator Fuel Demand)
06 TORQUE INPUT % and 03 SCALED ACT COMMAND % is the percentage of
rated engine load. Proper setting provides a 0% signal at minimum engine load
(no-load) and a 100% signal at maximum engine load (rated load) based on
either the torque sensor input or the actuator fuel demand output. Load sharing is
primarily provided by the torque sensor analog input. However, should the torque
sensor analog input fail or not be provided, a scaled actuator command signal is
provided by the scaled actuator command %. The no-load and rated load torque
input and scaled actuator command settings are found in service mode, under
the header L**ACT / TORQUE CALIB**, at prompts 01 ACT OUT % @ NO
LOAD, 02 ACT OUT % @ MAX LOAD, and 04 TORQUE IN @ NO LOAD, 05
TORQUE IN @ MAX LOAD.
Torque Input
The torque input produces the TORQUE signal used for torque sharing. The
torque signal is produced from a set of strain gauges on the engine drive shaft.
Torque sharing automatically switches to using fuel demand (actuator current)
when the torque input signal is not provided or failed or if there is a torque
deviation between the two engines.
The calibration of the torque input is done at two positions, the minimum torque
position and the maximum torque position, or no load to full load.
After calibration, the 06 Torque Input % shown on the A**DISPLAY 1** service
menu should be compared to confirm good correlation at both minimum torque
(minimum load) and maximum torque (maximum load).
Start Fuel Limiting
The start fuel limit is set to limit actuator driver output during starts to minimize
smoke, overfueling, flooding, or cylinder wash down. Upon starting, the actuator
will open to the 01 START FUEL LIMIT based on actuator percent. If the engine
does not immediately start, the actuator percent will increase at the 02 START
RAMP RATE (%/S) until the engine starts or until the max fuel limit is reached.
The start fuel limit remains in effect until engine speed reaches 95% of the speed
reference set point and the speed PID is in control for 1 second at which time the
start fuel limit is removed. The start fuel limit is reactivated once the engine is
completely stopped and restarted. The start fuel limit and rate set points are
found in service mode, under the header H**START/ MAX LIMITS**, at prompts
01 START FUEL LIMIT and the 02 START RAMP RATE (%/S). To disable the
start fuel limit function, set the limit to 100%.
Woodward
The fuel limiting and torque sharing functions both depend heavily
upon accurate L**ACT / TORQUE CALIB** settings. Carefully
determine and enter the L**ACT / TORQUE CALIB** settings and re-
verify these settings following any related mechanical changes
(linkage, actuator. etc.). Be sure to compare both the 03 SCALED
ACT COMMAND % and the 07 TORQUE INPUT % for the full range of
loading operations. Failure to do so may result in incorrect load
sharing operation.
723PLUS Digital Marine Control
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