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Thread: Fast Pulses with Sharp Edges

  1. #1
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    Jun 2009
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    Default Fast Pulses with Sharp Edges

    Above title should have read "RayMarine ST4000 Ram motor" instead of "test."

    In preparation for RtR, I needed to replace the electric motor of my X5 Ram. It uses a basic Mabuchi RC-555SH hobby motor but with some additional cross wiring near the neg and positive terminals.

    What are the 4 wires? I suspect they may have to do with handling the sudden change in current direction and voltage.

    I have found this on my 2011 model ram and a 2014 model. Crazy Rhythm did not have this on his RAM which is about same circa.

    Name:  AP Mabuchi 555SH motor small pic.JPG
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    Last edited by BobJ; 07-26-2020 at 09:48 AM.

  2. #2
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    It appears the 4 wires serve to put 3 capacitors into the mix... one bridging +/- and one each connecting positive and neg to the case ground.
    I can't read the numbers on the capacitors, so the specifics aren't possible, but they are likely there to smooth out the current spikes, as you mention.
    The 2 on the ground wires probably serve the ensure current only moves to the ground, and not back to the other motor pole.

    Full disclaimer, my knowledge about Ray Marine products is limited, there are certainly others who know more.
    paging Dr Boschma...
    DH
    Last edited by DaveH; 07-23-2020 at 10:46 AM.

  3. #3
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    THey are there for noise suppression to pass FCC and EU specs on radio interference. They would have some impact on current flow but they are quite small in value to do much. If you have an SSB aboard, for example, these would lower some of the weird tones you hear when the motor is turning in any direction on some frequencies. VHF likely not quite as sensitive. The signal to the motor is not a pure DC signal, it is a series of fast pulses with sharp edges that create quite a bit of electrical noise.

  4. #4
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    Jun 2009
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    Thank you very much guys!!

    My hope is renewed that I will be there for Round the Rocks!

    BTW, "..it is a series of fast pulses with sharp edges..." That descriptive phrase takes me immediately back to SHTP 2014. The whirring and grinding noises not only resonated inside the small cabin but tortured and grated my sleep. In time, it became the background rhythm to my dreams like the theme music in "Shaft."

  5. #5
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    Jun 2009
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    My AP is fixed and wet tested for a few hours so I will be there for RTR. During the test, I saw this UL looking good and screaming out of the RedRock. Some magnification showed it to be Dave on his Olson Sled. I finished the repair without adding any of the bridged wires on the terminals. I don't run comms that would be interfered. Good thing because my soldering and electrical skills are rudimentary.

    I found it beneficial to keep ram sections loose for dry testing on boat. For example, if you hear the motor turning and seizing, then 4 pins on the jack screw probably didn't engage the planetary gears correctly. I found it best to place planetary gears on the pins, then insert into pinion gear housing.

    Also important when reassembling at bench, seat the motor into the black aluminum casing so that the black screw at the top of the motor fits into one of the two available recesses inside the black plastic coupler. This functions to keep the motor from spinning inside the housing.

    I have always wanted to see the guts of my ram and learn how these work. But if you don't have the time or inclination, Raymarine charges $200-$260 and $600 for brand new. BTW, they have ceased their online tech forum.

    $5 dollar electric motor at https://www.parts-express.com/mabuch...-36mm--125-566
    Raymarine has the motor with the bridge wires for about $100, part number I believe is Q114.

    Some help in removing gears for the motor. https://jeanneau.proboards.com/thread/2127. I used some shims and red loctite on my pinion shaft to help retention. The RM shaft has some built in edges that help with this.

    I think it's important to take the Ram apart after a few seasons to lubricate the internals and inspect the insides. Water and salt does get inside (cover anyone one?!). Despite what some think, it's OK to manually push down the piston into the RAM housing as this is part of the test procedure. If it moves stiffly or not at all, time to service. The link below has schematics and test procedures at the back to help in repair of ST4000 RAM. Also has wheel pilot stuff, too. I could not find the legacy documents on RM's site.

    https://jgtech.com/pdf/S1%20Tiller%2...%20Service.pdf
    Last edited by Submarino; 08-04-2020 at 07:59 AM.

  6. #6
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    Sep 2008
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    Quote Originally Posted by Submarino View Post
    I could not find the legacy documents on RM's site.

    https://jgtech.com/pdf/S1%20Tiller%2...%20Service.pdf

    Is there anything helpful here in this big pile of manuals?

    https://l-36.com/manuals.php?menu=6

  7. #7
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    Jun 2009
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    Thanks for the link. That's quite a collection of manuals.

    I found the ST4000 manual and it's a duplicate of the jgtech link.

    However, there is a bunch of other stuff that could be handy in the future!

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