[DG] [DG11] DRIVE STOPPED troubleshooting

[alx]

Hello all!

A friend of mine has a large schooner with an Evolution autopilot system installed.

The ACU is the ACU-200 (I believe) with a p70 display, driving a Jefa 200 Nm drive unit with a sprocket that connects via chain to the steering gear (http://www.jefa.com/steering/products/dr...50nm.htm). There is a rudder reference sensor attached to the steering gear that provides rudder position feedback.

We're encountering a problem where the autopilot will steer successfully for a while and then give up with a DRIVE STOPPED message, somewhat randomly. Some data points we've collected so far:

* Most of our autopilot usage has been motoring in calm to light conditions, with little load on the rudder as a result.
* The unit steers well and steers consistently up until the moment it drops out.
* Once it drops out, if it is reactivated it does seem to drop out more frequently, within minutes. If the boat is hand steered for a while, it seems to last longer when reactivated (we've been very scientific about gathering this data as you can tell).
* Tuning responsiveness has little impact.
* The system was installed a year+ ago, but as we have no MFD aboard the software has not been updated since then. I plan to perform that update at some point soon.

We're now looking to attack this problem and are looking for any troubleshooting suggestions or settings we can tune. Or were there any bugs in the older Evolution software which could cause this problem that updating might resolve?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum alx,

The reported symptoms would not be associated with a software problem. The symptoms reported are those of an ACU has interfaced to a load which exceeding the design of the ACU or an ACU which is failing. As the ACU's components heat up in response to the load, the time between such drive stop failures would be expected to decrease should the system be restarted. Continued use may lead to complete failure of the ACU. When recommending an ACU for use with a third party rotary drives, an ACU400 would typically be recommended.

[phanty]

Hello,
We have the exact symptoms our p70, Evolution & ACU 200 fail to guide our 12 ton Najad 405 with the message drive stopped, no warning the pilot disengages particularly when under load. It seemed better for a while in Leisure mode but yesterday it disengaged all day as we crossed from St Pierre, France to Newfoundland, Canada. Winds were 10-15-20-30 with 1-2-3 meters seas. If purchasing a new ACU 400 will fix this I’ll do so right away. We still have to get up the Newfoundland coast to St John’s and Lewisporte. We’ve had the problem all summer but it’s getting worse.
Thanks,
Mike
SV Loon’s Lace

[Derek - Raymarine - Moderator]

Hi Mike,


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.

Regards
Derek

[phanty]

Hi Derek,
We’ve run through the setup options many times, tried the different modes and updates all the firmware. Under difficult conditions the motor still stops so we’ve ordered a 400 series unit. It soundsi like thats what should have been installed to begin with because we have a heavy boat, 24000 lbs and Mamba steering with a Keanow (sp) rotary drive.
Is there anything I can do through Raymarine to return my type 200 ACU?

Mike

[Derek - Raymarine - Moderator]

Hi Mike,

Where did you buy the ACU from? the first point of contact would bee with them.

Kind regards
Derek

[phanty]

Derek it came with the boat, new to us last year. I’ll see if someone on kajiji wants it. We have the boats old radar and e80 chart plotter to sell too.

[Derek - Raymarine - Moderator]

Hi Mike,
Good idea
you're welcome
Thanks
Derek

[Kwolfel]

Good afternoon

I own a 2004 Leopard 47 catamaran with a Raymarine ST7002 autohelm.
It has a type II drive unit and I believe an ACU-400 processor.

In the past month it has begun having issues showing Current Limit and occasionally Drive Stopped on the display and then goes back to standby.

The part I do not understand is after about 15 or 20 minutes of doing this it begins to function normally and will be fine for the rest of the day, even under difficult sailing conditions with huge following seas. Where do I begin troubleshooting if it works fine once it has "warmed up"?

[Derek - Raymarine - Moderator]

Hi KWolfel,

Thank you for your enquiry,

CURRENT LIMIT specifically suggests that the drive is taking too much current and the course computer is alarming to indicate that it thinks it is too heavily loaded, coupled with DRIVE STOPPED suggests that the electric motor in the drive is not operating or the rudder reference unit is not indicating rudder movement.

Please carry out the checks referred to here to investigate further.

it is possible that if this is the original drive fitted to the boat - it will be quite old as identified by the ST7002 control unit, so possibly the electric motor is becoming faulty - taking too much current or the brushes are worn.

Thanks
Derek