Woodward ProAct I, Product Manual

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ProAct I/II Manual 04121
16 Woodward
Torque Limit
A two-slope torque limiter is provided for mechanical-drive, variable-speed
applications. The torque limiter provides a maximum fuel position determined by
current engine speed to limit over-fueling. The torque limiter is compared with the
maximum fuel limit and the lower percent value is used as the actuator position limit.
Figure 2-4. Torque Limit
Speed Reference and Ramps
The ProAct control provides discrete local control of the speed reference with
switch inputs to issue raise and lower speed commands. For remote speed
setting, the control permits a 4 to 20 mA input which is used to vary the speed
reference. This section describes the operation of each of the speed reference
and ramp functions and their relation to each other. Read this section carefully to
be sure your switch gear sequencing provides the proper operating modes.
The control provides an Idle/Rated discrete input with tunable Idle and Rated
Speed settings. Raise and Lower inputs will raise and lower the speed reference
at tunable rates.
The Idle Speed set point is provided for engine start-up or cool-down speed. Idle
speed may be set equal to or less than the Rated Speed set point. Idle Speed is
independent of the Lower Limit set point and may be set to a lower speed. When
Idle is selected (Idle/Rated switch in Idle position with contacts open), Remote
Speed Reference and Raise and Lower inputs are disabled. Idle speed cannot
be changed except through programming the Idle Speed set point. The Idle
Speed set point value can be changed using the hand held or PC when the
engine is running, however the idle speed of the engine will remain at the
previous set point until the Idle/Rated or Run/Stop switch has been toggled, or
power cycled on the control.