Rotating power slip ring

Discussion in 'General Electronics Chat' started by Leigh, Mar 18, 2015.

  1. Leigh

    Thread Starter Member

    Feb 11, 2010
    20
    3
    Hi,

    I have built a rotating slip ring that feeds 24V from a power supply to a rotating cluster of led's hanging off a mirror ball motor. The rotating disc has two tracks made of circular copper strips. The voltage is applied to these rotating strips via multi-stranded copper flexible wires that are held against the copper strips under sprung tension. It works fine, but I am wondering if there will be chemical activity between the two copper elements of the device that will degrade performance over time? Some kind of electrolysis? I know there will be gradual mechanical wearing of the two parts.

    What do you folk think?

    All the best,

    Leigh
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Copper will oxidize but I'd hope the wiping action of the slip ring should keep it clean there..
    Tin or silver plating the copper should help.
     
  3. alfacliff

    Well-Known Member

    Dec 13, 2013
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    electrolysis requires dissimilar metals, copper to copper will not. you can get friction rubbing the copper down thinner, and corrosion. there are greasses that will lube the copper and protect it from oxydation.
     
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    This is essentially a brushed motor format. You could buy some carbon brushes and springs to keep the carbon "brushes" pressed against the copper ring. Easiest would be to buy a brush replacement kit for a Dremel tool. Carbon will not corrode and will not cause corrosion. Really depends on how long you want this to last, how smooth your copper ring is (and how many spark and associated spark-endured erosion you get). The lower the voltage (fewer LEDs you have in series) will cause less spark-enduced erosion. Same is true for a smooth copper ring (less make/break contact leads to less sparks).
     
    strantor and djsfantasi like this.
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You could also have looked at designing/modifying the pickup and rotor from a Automotive Alternator from a auto wrecker, this has two slip rings and brushes and normally carries around 2amps average.
    Bearings and all would be in place.
    Max.
     
  6. Leigh

    Thread Starter Member

    Feb 11, 2010
    20
    3
    Thanks for everyone's thoughts on the subject. I really appreciate them. One challenge was to construct the slip ring around the constraints of the mirror ball motor. My 3d printer was very useful to achieve that. It meant that I couldn't use "off the shelf" components. I think carbon brushes and springs would be better, but the copper ring is probably not smooth enough, and abrasion would be excessive. The current solution works well, with no sparking, I just have to see how long it runs before wear and tear and air-born dust becomes a problem.

    Again, thanks!

    Leigh
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
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  8. strantor

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    Oct 3, 2010
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  9. mcgyvr

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    Oct 15, 2009
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  10. John P

    AAC Fanatic!

    Oct 14, 2008
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    One problem I can see with the Adafruit products is that the slipring isn't hollow. If it's going to be a motorized device, the rings could be above the motor, but that means that the wires must pass through the motor, or the motor has to be off to the side with a pulley or other mechanical drive using a hollow shaft. If it's a mirror ball setup, then I assume that the ball hangs below the motor, so those Adafruit things don't look usable.
     
  11. Leigh

    Thread Starter Member

    Feb 11, 2010
    20
    3
    That's right John. Sadly those beautiful little slip rings don't suit my application. But they certainly are great for other situations. Thanks to those who suggested them :)
     
  12. Leigh

    Thread Starter Member

    Feb 11, 2010
    20
    3
    Thanks for the lube suggestion. That could help. I'll trial it.
     
  13. sen15

    New Member

    Jun 23, 2015
    1
    0
    This company have miniature capsule slip ring and small size through bore slip ring maybe suitable for you.
    See: http://www.arslipring.com
     
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