[DG] [Dg11] Drive stopped issue

[vmi2uscg]

Drive Stopped issue

I have a 2 year old ACU-200 controlling a much older Type 1 mechanical linear actuator. The display is an i70 unit. Boat Particulars: 37' sailboat, approx 20K lbs.

On my last trip, I got the "Drive Stopped" error while motoring back at approx 5 knots, the autopilot dropped out. In testing afterwards, at the slip, it only drops out and displays "Drive Stopped" only when I order a course change. The clutch works fine and locks the helm when I engage the AP. The helm and the rudder both move freely.

Since then, I've cut each power cable to good copper and reconnected everything. No change.

I've checked the brushes on the actuator; they are fine.

I measured the output voltage of to the from the Drive power connections and it is 7V, exactly, when I order a heading change. Power is supplied to the ACU by 10 GA cable from the breaker and measures 13.5 volts at the dock while I'm on the charging. I've measured the voltage on under the caps for the brushes, and get 7 volts there, so I know the power wires to the actuator are good.

7 volts seems a bit low. I thought I'd be getting 12V out from the ACU. I've pulled the cover off the ACU and can't signs of damage. I'm a bit lost now, the unit is two years old and rarely used. Anything else I can check?


Before replying, ask yourself, what would Admiral Adama do?

[Derek - Raymarine - Moderator]

Hi vmi2uscg

Thankyou for your enquiry,

The clutch operation sounds correct, when AUTO is selected the wheel should feel locked, the most common cause after the clutch failure is the motor brushes, they could either be worn or sticking in the brush holders.

This can be checked by temporarily dabbing the motor wires onto the main power into the course computer/ACU and check the operation of the drive - if the motor is noticeably more powerful and brisk in terms of operation, then the cause can only be a high resistance connection in the cables between the ACU and the drive or the ACU itself.

Note that for small course changes the ACU will not output a full 12v anyway, if you select 4 x +10, then you should expect to see closer to 12v when the drive is connected, also note that with no drive connected the ACU will detect that and reduce the output voltage too.

Finally check through calibration to make sure the correct drive is selected, try resetting the pilot to revert to factory settings in case ther eis an isse there too.
Regards
Derek