Woodward ProAct I, Product Manual

Page: 49 / 67

Manual 04121 ProAct I/II
Woodward 47
Damage to the butterfly valve and possible jamming of the valve in
the wide open position is possible if linkage is not designed to reach
maximum actuator position at least 3° in advance of maximum
butterfly valve position.
The Maximum limit may be used to limit the horsepower developed in the
engine.
2.
Transient Limit is used when the maximum fuel limit is controlling the output
horsepower of the engine. The transient limit allows overfueling of the
engine by the amount tuned into the control. This allows the engine to
accelerate to the rated load.
3.
Transient Time is the amount of time that the Transient Limit is allowed to
operate.
4.
Start Fuel Limit is a limit that is in place while the engine is starting. This
limit helps reduce smoke on diesel engines and prevents overfueling during
the start of gas engines. The limit is removed when the engine reaches Start
Speed.
5.
Start Ramp is a tunable ramp of the actuator output to ensure starting of
cold engines. The control ramps the position of the actuator from the Start
Fuel Limit open at a controlled rate until the engine starts. After the engine
has started, the fuel limits will be set by the Maximum Fuel Limit or the
Torque Limit, whichever is less.
6.
Start Speed sets the speed in rpm that will remove the start-fuel limit from
the control system. When Start Speed is obtained, the speed ramps to idle
or rated speed, depending on the selection made. After start speed is
attained, the control uses the Maximum Fuel and Torque limits.
7.
Minimum Torque Limit is the percent actuator output allowed when the
engine speed is at or below the Lower Limit speed setting (Menu 3). The
torque limiter provides a value between Minimum Torque Limit and
Breakpoint Torque Limit when engine speed is between these two settings.
This sets the torque limit slope below the Breakpoint position.
8.
Torque Limit Breakpoint (BP) is the engine speed at which the slope of the
torque limiter output changes. The Torque Limit Breakpoint must be set
between the Raise and Lower Limits described under Menu 3.
9.
(BP) Torque Limit at Breakpoint (BP) is the percent actuator output at the
engine speed set by the Torque Limit Breakpoint described above.
10. Maximum Torque Limit is the maximum percent actuator output when the
engine speed is at the Raise Limit speed setting. The torque limiter provides
a value between the Breakpoint Torque Limit and Maximum Torque Limit
when engine speed is between these two settings. This sets the slope
above the torque limit breakpoint setting.
Figure 4-12 illustrates the breakpoint and these adjustments.