Woodward ProAct I, Product Manual, Page: 24 / 67

ProAct I/II Manual 04121
22 Woodward
Actuator Installation Considerations
Thermal
The actuator is designed for installation on the engine. The actuator will generate
heat, especially when stalled.
The feedback sensor located on the actuator has a maximum temperature
limitation of 125 °C (257 °F). Should the actuator be shielded from air circulation,
the installer must consider the heat conductivity of the installation bracket, and
the operating temperature of the ultimate heat sink to which the bracket will be
attached. Generally the heat transfer abilities of aluminum and low-carbon steel
are better than high-carbon steel or stainless steel. Contact Woodward if
operating temperature is a concern.
Output Coupling or Linkage
The actuator will provide up to 75° rotation from minimum to maximum positions.
This will allow direct installation to most butterfly shafts. Special connectors that
permit the installation of the actuator directly to a butterfly valve shaft are
available. The coupling selected (or any linkage used) must be of zero backlash
design. If a coupling is used it should be drilled and pinned, or serrated.
The bracket that mounts the actuator must be of adequate precision to assure
that misalignment limits of the coupling used are not exceeded. Contact
Woodward for help in selection of an approved coupling.
Diesel engines will generally useless rotation, often about 30 degrees. Linkage
should be designed to use as much actuator rotation as possible to take
advantage of the actuator’s full work capability. (If only 30 degrees of actuator
rotation is used, the actuator will provide only 40 percent of its work capability.)
Fuel Position Stops
Diesel installations will generally use the fuel system minimum and maximum
position stops. The actuator travel should be centered within the total rotation
needed from minimum to maximum fuel.
Diesel engine racks are normally designed to provide the minimum and
maximum stops without binding.
Butterfly valves in carburetors will often bind if rotated too far toward minimum or
maximum. For this reason, the stops in the actuator should be used at both
minimum and maximum positions. Note that the stops will allow up to 3° of
additional rotation in both directions during impact.
Make sure that the engine will always shut down when the actuator is at the
minimum stop.