DRIVE STOPPED indicates one of several issues,
1) The ACU has detected that the rudder is not moving in response to requested drive output
2) The ACU has detected a drive over current and so has stopped outputting power to the drive in order to protect itself
3) The Drive motor has stopped/ failed in some way, motor open circuit, poor connections in the cables, sticking brushes in the motor or failed clutch.
Initially follow the advice
here to test the drive and eliminate an issue with the rudder reference unit - point 1) and drive unit itself - point 3).
Referring to point 2)
this FAQ here details possible reasons why the ACU may overheat and so lead to a shutdown.
In cases where a 3rd party drive is fitted, we recommend an ACU400 be used
as described here in order to be sure the ACU is not overpowered by the drive during starting/ reversing or operating at full load.
If the ACU is overstressed and shuts down due to overload, then the system may also revert to STANDBY in order to protect itself.
In addition to the above, also check the RUDDER DAMPING setting in calibration, if the autopilot is constantly moving to and fro or is being overloaded, increasing the RUDDER DAMPING in the Autopilot calibration to 7 or 8 will reduce the operating cycle of the autopilot, reduce the rudder movements and reduce the current consumed by the Autopilot as well as reducing the build up of heat too, so may help ease the overload until such time as a proper assessment and replacement of the ACU with a larger one is possible.
RAYFAQ#
