Raymarine autopilot wiring question

[gscriba]

PO had only a positive and negative wire to the course computer from the clutch on the Raymarine ram. The wiring instructions call for a "ground" wire to be connected from the clutch to a ground post on the course computer. My questions are 1) what is the function of the ground wire from the ram to the course computer and 2), is the the ground wire required? 3), what size should said ground wire be (there is no mention in the manual/instructions). The AP has been working fine for years, but I have discovered this "issue" while moving the ram to a new fixed point.
Thank you in advance.

[BugzyCan]

What model of Raymarine is it? Did you check for an online manual?

[gscriba]

I have the manual. The answers to my questions are not in the manual, thus the post.
Raymarine Type 3 pump, hydraulic linear ram, ACU-400, EV-1 and p70s head.

[smac999]

the the system should have 4 wires. 2 for pump motor (A+B) and 2 for clutch (pos , neg). I don't know what you mean for a clutch ground. there is only 2 terminals on the cluth connection on acu.

and 2 power wires coming in from battery.

there is a chassis ground on the acu-400. maybe you are confusing it with this. which is nothing to do with the ram or pump. it goes to battery ground.

[smac999]

looks like the ram also has a chassis / RF ground. shouldn't really be needed. connect the ram and ecu chassis ground to the battery neg. as it says in manual. the manual says 12awg. don't just join the 2 together. that will create issues not solve them.

https://hudsonmarine.co.uk/uploads/R...structions.pdf

[surazo]

Hi , I have the same autopilot and is correct that you need to understand the + and - in the computer like to extend or retract the arm .I suffer the clutch fail and I understand that ,The electric motor of the arm need to be connectedto ground as is shown in the diagrams attached .
regards

[gscriba]

Thank you for the info. Not sure how I overlooked that in the manual. Thanks again. Will definitely need to upsize the clutch wires and will add ground wires from both the ACU as well as the ram.

[Tikitour]

Hi,

I am having some problems with my autopilot and need some help! Here is what is happening:
I have a newish 2018 Raymarine autopilot with a hydraulic linear drive, currently it stopped working and upon investigating found that the hydraulic motor for drive was completely burnt up. I have found someone to help source me with a new motor but my question now is with the ACU. I have a Raymarine ACU 400 that is currently getting 12V in however the output to the drive motor is only around 6-7 V. I called Raymarine and they said that was faulty and needed to be sent to Raymarine for repair. Does anyone have any experience with low output our if ACU? I’m not sure if the low output burnt the hydraulic motor as it requires a direct 12V.
Thanks

[goboatingnow]

Originally Posted by gscriba

Thank you for the info. Not sure how I overlooked that in the manual. Thanks again. Will definitely need to upsize the clutch wires and will add ground wires from both the ACU as well as the ram.

The ground wires are not necessary for operating the ram or clutch in my case I never connect them as I will will not have DC grounded to seawater devices on board.

Ray provides this for EmC reasons but no load corrects flow in these grounds

In the case of the ram drive the output circuit is a H drive and hence drive currents flow from one side of the H bridge to the other side depending on which direction is selected. The current then returns via the ACU DC power feed return. It does not return via the case ground lug.

[goboatingnow]

Originally Posted by Tikitour

Hi,

I am having some problems with my autopilot and need some help! Here is what is happening:
I have a newish 2018 Raymarine autopilot with a hydraulic linear drive, currently it stopped working and upon investigating found that the hydraulic motor for drive was completely burnt up. I have found someone to help source me with a new motor but my question now is with the ACU. I have a Raymarine ACU 400 that is currently getting 12V in however the output to the drive motor is only around 6-7 V. I called Raymarine and they said that was faulty and needed to be sent to Raymarine for repair. Does anyone have any experience with low output our if ACU? I’m not sure if the low output burnt the hydraulic motor as it requires a direct 12V.
Thanks

You can test the output of the H bridge drive to the ram motor easily. Activate the pilot confirm your acu power leads are supplying 12v. Then test the motor connections with a DMM with the ram motor detached.

If you have 12v then the chances are the H bridge is alright. If you have 6v approx. The H bridge is indeed damaged.

If you have 12v the next is a load test but you need a suitable DC load.

[Tikitour]

Hi, thank you for your reply. So I have measure the output from ACU to hydraulic drive motor and I have 6-7V. Does this mean that the ACU is damaged? Is there a way to repair the ACU? I am in a remote location and getting it to Raymarine in US would be challenging.
also how can test voltage at the H bridge?

Also I have come across this forum response to someone else that talk about lower voltage for soft starts, I will attach picture of response.

[goboatingnow]

Originally Posted by Tikitour

Hi, thank you for your reply. So I have measure the output from ACU to hydraulic drive motor and I have 6-7V. Does this mean that the ACU is damaged? Is there a way to repair the ACU? I am in a remote location and getting it to Raymarine in US would be challenging.
also how can test voltage at the H bridge?

Also I have come across this forum response to someone else that talk about lower voltage for soft starts, I will attach picture of response.
Attachment 265256

Ah yes I completely forgot about that. To test the bridge you’ll really need a scope as a dmm will under read a PWM waveform.

In my experience the H drive is very robust so unlikely to have failed.

[Tikitour]

Thanks for helping again, you seem to be knowledgeable on these units.
I will try and test the H-Bridge, are there any schematics for this? If it is unlikely to fail what else could it be? I am definitely only getting 6V to motor with it disconnected. What recommendations do you have for repairing this? Is the best option to book it in online with raymarine?

[Sivaa]

To be checked by opening the unit . Transistor or regulator - may come in your way .

[goboatingnow]

Originally Posted by Tikitour

Thanks for helping again, you seem to be knowledgeable on these units.
I will try and test the H-Bridge, are there any schematics for this? If it is unlikely to fail what else could it be? I am definitely only getting 6V to motor with it disconnected. What recommendations do you have for repairing this? Is the best option to book it in online with raymarine?

As was mentioned the H bridge is a PWM drive so a scope is really needed.


You can easily verify the motor is ok with 12v feeds. So after the hit has to be the ACU. The H bridge components are easily indentified but you need good pcb repair tools.

So yep , book that raymarine repair.