Woodward 721, Руководство по эксплуатации и калибровке

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Manual 26004 721DSC for Marine Propulsion Application
Woodward 25
Dynamics 2
Dynamics 2 is enabled when external contact H (Main Shaft Clutch On) is closed.
1. Idle Prop. Gain 2
This set point is effective while Start Speed is selected as the speed reference. (Hence,
contact B is open.) Idle Prop. Gain determines how fast the control responds to an error
in engine speed from the speed reference setting while the Start Speed is selected.
2. Rated Prop. Gain 2
Adjust this set point to get the stable engine operation above and below the rated speed
with light load or no load. Rated Prop. Gain determines how fast the control responds to an
error in engine speed from the speed reference setting while the Rated Speed is selected.
3. Integrator Rate 2
Integrator Rate compensates for the lag time of the engine. It adjusts the time required
for the control to return the speed to zero error after a disturbance. Integrator Rate is
adjusted to prevent slow hunting and to minimize speed overshoot after a load
disturbance.
4. Derivative Ratio 2
Derivative Ratio compensates for the actuator time constant. Set this set point to 5 for
ordinary applications.
5. Window Width 2
Window Width is the magnitude (in rpm) of a speed error at which the control
automatically switches to fast response. The control does not use the absolute value of
speed error, but “anticipated” speed error to make this switch. This method provides for
quick switching to the high gain value when an offspeed occurs and early switching to
the low gain value when recovering from the speed transient. This provides smoother
switching than if the absolute speed error was used for the window.
6. Gain Ratio 2
Gain Ratio is the ratio of the Gain setting at steady state to the Gain setting during
transient conditions. The Gain Ratio operates in conjunction with the Window Width
and Gain adjustments by multiplying the Gain set point by the Gain Ratio when the
speed error is greater than the Window Width. This makes the control dynamics fast
enough to minimize engine
-
speed overshoot on start
-
up and to reduce the magnitude of
speed error when loads are changing. This allows a lower gain at steady state for better
stability and reduced steady
- state actuator linkage movement.
Speed Settings
Set set points for speed references.
1. Start Speed
Start Speed is the speed reference selected when the Start Pos/Idle contact (external
contact B) is open.