Re: [Amel Yacht Owners] Re: A54 Sleipner bowthruster uneven brush wear

Sv Garulfo

Hi Bill and 54 owners,

The issue with the Port-only-thrusting was resolved by removing and dismantling the double-solenoid power relay. After cleaning the contacts with sandpaper and corrosionX-ing the springs, it functioned correctly again. The issue was confusing because each relay would behave correctly independently (connecting the top posts and disconnecting the bottom ones) but activating the starboard one would cause the other one to loose its bottom (idle) connection(!). 

Some more info I gathered in the meantime:

* The front relay (red and blue wires) is activated for starboard operation. The back relay (red and grey wires) for port. 
* Power cables are marked A1, A2, D1, D2. A1 and A2 are the stator posts, D1 and D2 are the rotor bobin posts.
* the rotor and stator circuits are in series. The voltage of the rotor is reversed depending on direction. 
* A1 is permanently connected to batteries Neg. A2, D1 and D2 are controlled by the relays. 
* on idle, A2, D1 and D2 are connected together. 
* on Starboard, the front relay connects D2 to batteries Pos (top posts). A2 and D1 are still connected by the bottom posts of the back relay. Circuit is: Pos=D2-rotor-D1=A2-stator-A1=Neg
* on Port, the back relay connects D1 to batteries Pos (top posts). A2 and D2 are still connected by the bottom posts of the front relay. Circuit is: Pos=D1-rotor-D2=A2-stator-A1=Neg

Hope that will help,

Fair winds and happy thrusting

(Oh, and the ground circuit leak got resolved too in the operation. Not sure exactly how, but it did)

AMEL 54 #122

On Mon, 28 May 2018 at 21:43, S/V Garulfo <svgarulfo@...> wrote:
Hi Bill,

I agree the motor is probably fine, as it can run in one direction. 
I can hear the big Albright double-solenoid motor-reversing contactor click for both starboard and port operation. So joystick is innocent.

I think i know what 4 relays you mean (in the plastic junction box) but didn't foresee they played a part in the thrusting operation. I assumed it was only the raising/lowering of the thruster, and that my problem was closer to the Side-Power unit. 

I measured voltage on the Albright contactor posts in port/starboard/idle operation to see if I can reverse engineer what is supposed to happen to the 4 power cables going into the motor. Need to look at the results with a fresh pair of eyes in the morning. And maybe I'm barking up the wrong tree.

Thanks as always,

AMEL 54 #122

On Mon, 28 May 2018 at 21:02, Bill Rouse brouse@... [amelyachtowners] <amelyachtowners@...> wrote:


It is probably not the motor and is either the joystick or one of the 4 relays. 

Eliminate the joystick first. 

It is unlikely that your relays are numbered because out of about 10 54s, I have only seen 1 with numbered relays, but they are all the same relay. If all 54s are wired the same, I think it will be relay #2, but, if you have a spare relay, it is easy enough to replace them one at a time until you find the culprit. Of course the problem can be corrosion between the relay terminals and the female spade connectors.

If I owned a 54, I would have 4 spare relays.

Good Luck!

On Mon, May 28, 2018 at 4:22 PM, 'S/V Garulfo' svgarulfo@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi Scott,

Talking of the devil...

I haven't looked into the carbon dust and brushes yet, cause I reconnected the thruster for a quick stop in a marina and after the initial 'all-good' tests, it decided to only thrust to port and not starboard....
So I've got a second issue to troubleshoot. If anyone has experienced it and has clues, it's very welcome. 

I'll check the state of the brushes for uneven wear too, to give you another data point. 
Note that i don't have an oil reservoir in my unit.

Fair winds to all,

AMEL 54 #122

On Mon, 28 May 2018 at 05:54, cpp_berkeley <no_reply@...> wrote:


Answers to your questions below:

1) After we let it cool down (~30 minutes) it ran fine. Perhaps a bit weaker but that's probably to be expected considering that some of the brushes have worn down considerably and actually even cracked, exposing just bare conductors. My fear is that going forward, it will continue to overheat prematurely and leave us without a bow thruster when we most need it.

2) The sidepower bowthruster has a drain plug underwater between the two props and a fill reservoir in the bow locker. Obviously oil is changed on the hard. My understanding is that the way to change the oil is to open the plug and continue filling the reservoir until the oil coming out of the plug looks clean. That way, you don't get air into the system.

The mechanic drained all of the oil and he put the plug back and filled the reservoir. The next day, the oil level had dropped, indicating that the air migrated upwards (and/or the thick oil slowly migrated downwards). This drop in oil level continued for a few days. It seems reasonably stable now, but I'm unsure whether some air was still stuck in the gearleg and never made its way out..

Also, we now have a strong "Mass -" leak. Thomas of S/V Garulfo posted that he had a bow thruster leak, possibly from carbon dust. I'll go check that now and report back.

But in general, any idea why the carbon brushes would be wearing so unevenly?


A54 #69 

S/V Tengah 

---In amelyachtowners@..., wrote :

Hi Scott,

Your post raises a couple of questions. 
1. You say the unit had a thermal shutdown - did it work after it cooled  down?  Any problems?
2. In what way did the mechanic have trouble getting air out of the system? On the SN and SM one simply turns the bottom section upside down to drain and then pours in new oil. No issue with air. Perhaps the 54 is a different design that I'm not familiar with.


Hi all,

I was coming into the quay at Zante yesterday in our A54 with about 10-15 knots on the beam and used the sidepower bow thruster in 10-15 second bursts and all of the sudden, thermal shutdown!

After executing an exciting no thruster stern-to med mooring into a tight spot (with expectant spectators!) I opened up the bow thruster compartment to see a lot of carbon dust. I took the motor cover off and inspected the brushes and found that for each of the pairs (4 pairs, 8 total brushes), one was worn MUCH more than the other one. On some pairs, it's the top one that was worn more, on some, it was the bottom one. Some brushes were down to loose wire.

On the attached photo, you can see the extent of the uneven wear for one pair.

We recently had the boatyard change the bowthruster oil and they drained it all before adding new oil, which resulted in challenges getting all the air out of the system. We then completed a 1350 mile passage. These probably have nothing to do with it, but maybe I'm wrong.

Before I go out and spend money to replace the brushes and possibly experience similar uneven wear, anyone have any ideas as to why this happened and how to rectify it?



A54 #69 

S/V Tengah 


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