ESC question

Discussion in 'Propulsion' started by metaphysics1221, Jun 2, 2008.

  1. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Peter, the precise value is not important, just make sure that the voltage rating of the caps is 5 times your nominal system voltage.
     
  2. metaphysics1221

    metaphysics1221 Member

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    Ok, so if I'm running on 6V I need to have a cap. that is rated at over 30V?
     
  3. admiraljkb

    admiraljkb Member

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    Make sure to review the ESC Lessons learned article:
    https://ntxbg.org/KnowledgeBase/?category_id=45&menuaction=phpbrain.uikb.view_article&art_id=12

    For cheap ESC the ProboatPRB2314 is pretty unbeatable value.

    For motors and such, those Johnsons are incredibly energy hungry, and will force you to beef up the electrical systems to compensate. Not sure precisely what you are trying to do, but Speed400 motors attached to gearboxes are generally good enough, and RC-Dymond's got a big sale going right now on them and gearboxes.

    Cheers
    Jeff
     
  4. metaphysics1221

    metaphysics1221 Member

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    I have read that, I'm a little confused on this point:

    If using a separate receiver battery – CUT THE RED WIRE on the servo lead from the ESC. If this isn’t done, the ESC will draw power out of the receiver battery, potentially frying the ESC, or it will give spotty performance after that and need replaced.

    Each of my motors has its own battery pack; does this mean I should clip the red wire going between the receiver and the ESC?
     
  5. metaphysics1221

    metaphysics1221 Member

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    I have a bunch of 50V .0 uF capacitors, would those be appropriate for capping my motors?
     
  6. admiraljkb

    admiraljkb Member

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    OK, well now I'm confused by "each motor has it's own battery pack". [:)] Each motor has it's own ESC and battery then? If so, then ONE of the ESC's would need to have the BEC disabled.

    If you have a separate battery for the RX and the motors, then you need to disable the BEC on the ESC (ala snip the red wire).

    For the caps, 3 caps rated 0.1µF (50 V) will normally work.

    Cheers
    Jeff
     
  7. metaphysics1221

    metaphysics1221 Member

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    Each of my screws operates as a completely separate system. This is because, as a research ship model, it needs to be very agile.

    The receiver also has its own battery. So imagine I only had one ESC with its own battery pack and that was hooked up to a receiver with a battery pack. Do I snip the wire?
     
  8. SnipeHunter

    SnipeHunter Well-Known Member

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    why dont you use a bow thruster? that would probably help agility a bit.
     
  9. admiraljkb

    admiraljkb Member

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    Separate RX battery is all I needed to hear. [:D] Snip the red wire my friend, as you aren't using the Battery Elimination Circuit on the ESC. It's also relatively easy to just pull the fitting out of the servo connector too if you want to easily reverse the process later on.

    Have Fun!

    Cheers
    Jeff
     
  10. metaphysics1221

    metaphysics1221 Member

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    I got both ESCs today, naturally they aren't wanting to work :)

    I followed the directions pretty carefully when attaching everything. Since that ESC is suppose to act as the battery for the receiver as well (problematic since I have two ESCs) I snipped the red wire from the ESC to the receiver.

    When I turned it all on, I followed the directions for programming the ESC with the stick movements. However, instead of turning, my motor started to, get this, hum. I'm serious!

    I tried everything I could think of, I:

    Reconnected the red wire. Nope.
    Reconnected the red wire and removed the receiver battery.
    Tested the transmitter/receiver separately (they work fine)
    Tested with a motor that had no capacitors
    Tested with a smaller motor
    Tested all the above motors with the same 6V pack of 4 AA batteries I was using to power the ESC circuit. They worked fine.

    The hum does start and stop when I move the stick so I figure the radio system must be working fine. The weirdest thing is; no matter what channel on the receiver I hook the ESC up to, only one stick does anything; thats the one that makes it hum. If I connect it to the other sticks it does nothing. Is it possible the ESC is picking up interference from the transmitter for some reason?
     
  11. Kotori87

    Kotori87 Well-Known Member

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    Listen very carefully, is it the motor that is humming, or the ESC? I know that all of my ESC's tend to beep in a high frequency, that you could probably call humming, when I'm using low throttle. Once I go up to high throttle, or go to full stop, the ESC stops humming.

    Does your radio have End Point Adjust (EPA) or Adjustable Travel Volume (ATV)? If so, they may have been turned down. That's about all I can think of that could be causing the problem, though.
     
  12. metaphysics1221

    metaphysics1221 Member

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    It's definitely the motor humming. My transmitter does have EPA but I have used all the channels before with no problem and they are adjusted correctly.
     
  13. Lou

    Lou It's just toy boats -->> C T D <<-- Admiral (Supporter)

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    Hey Guys,

    Looking at the thread the "Dimension Engineering Sabertooth" seems like a good deal.
    Is this the one? http://www.dimensionengineering.com/Sabertooth2X25.htm

    Anyone got pictures after waterproofing?

    Thanks in advance.
     
  14. SnipeHunter

    SnipeHunter Well-Known Member

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    Yes, thats the one I use in my VDT, I could probably get away with the 2x10 since the motors dont draw nearly that much underload but the added factor of safety is worth it to me.

    I can probably get some pics this evening for you if I remember, Ill write myself a note.
     
  15. Lou

    Lou It's just toy boats -->> C T D <<-- Admiral (Supporter)

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    Cool, thanks! Could this ESC drive a VV with two 550's?
     
  16. admiraljkb

    admiraljkb Member

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    It'd have to be waterproofed in some fashion.
     
  17. SnipeHunter

    SnipeHunter Well-Known Member

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    Here you go as promised.

    [​IMG]
     
  18. djranier

    djranier Well-Known Member

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    Lou I used the 2x10 in my Roma driving 4 650's with no problem, but it was close on the amperage, so I would do like Snipe did and go with the 2x25 just to be safe.

    I did lose the one when it got tangled up in Rick's Nagato stuffing tube. But they sent me a free replacement.

    Fluguel told me at Nats that he picked up the 2x10 for his VDT.
     
  19. Lou

    Lou It's just toy boats -->> C T D <<-- Admiral (Supporter)

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    Thanks guys, I have one on the way. Dave, did you scotch coat or epoxy?
     
  20. djranier

    djranier Well-Known Member

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    I scotch coated it, just make sure the switches are set right before you do. If you look at the Kumano build you can see it in the stern covered with scotchcoat. I have the 2x10 installed.