Cable-Pull Actuator
This is the motion element that transfers electrical energy to a cable over a pulley and pulls the engine's throttle lever. The type used in the GS740 and GS740-3P kits is a cable-pull servo motor; it is supplied with 12–24 V DC and sets the mechanical position of the throttle lever according to a remotely given command.
The motor inside the actuator turns the pulley through a gearbox, and the pulley winds the cable. As the cable shortens, the throttle lever is pulled in the opening direction; when the pulley turns the other way or the cable is released, the engine's own return spring pulls the lever to idle. That is, the system applies force in one direction only and the return is mechanical.
This arrangement has practical consequences. First, the throttle lever's return spring must be sound; a weak or dried-out spring causes the lever not to come fully down to idle when the cable slackens. Second, the force produced by the actuator must also overcome the friction in the cable, so the quality of the route is directly reflected in performance.
On AXI kits the actuator is mounted not on the engine block but at a point on the body with lower vibration and temperature; the engine's original mechanical throttle lever is left in place without being removed. On the GS740-3P there is a separate actuator for each engine and its position is continuously read by an AS5600 magnetic encoder.
Context in which this term is used: Electronic speed and throttle control on a diesel engine